numam-spdk/include/spdk/nvme.h

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/** \file
 * NVMe driver public API
 */

#ifndef SPDK_NVME_H
#define SPDK_NVME_H

#include "spdk/stdinc.h"

#ifdef __cplusplus
extern "C" {
#endif

#include "spdk/env.h"
#include "spdk/nvme_spec.h"
#include "spdk/nvmf_spec.h"

#define SPDK_NVME_TRANSPORT_NAME_FC	"FC"
#define SPDK_NVME_TRANSPORT_NAME_PCIE	"PCIE"
#define SPDK_NVME_TRANSPORT_NAME_RDMA	"RDMA"
#define SPDK_NVME_TRANSPORT_NAME_TCP	"TCP"

#define SPDK_NVMF_PRIORITY_MAX_LEN 4

/**
 * Opaque handle to a controller. Returned by spdk_nvme_probe()'s attach_cb.
 */
struct spdk_nvme_ctrlr;

/**
 * NVMe controller initialization options.
 *
 * A pointer to this structure will be provided for each probe callback from spdk_nvme_probe() to
 * allow the user to request non-default options, and the actual options enabled on the controller
 * will be provided during the attach callback.
 */
struct spdk_nvme_ctrlr_opts {
	/**
	 * Number of I/O queues to request (used to set Number of Queues feature)
	 */
	uint32_t num_io_queues;

	/**
	 * Enable submission queue in controller memory buffer
	 */
	bool use_cmb_sqs;

	/**
	 * Don't initiate shutdown processing
	 */
	bool no_shn_notification;

	/**
	 * Type of arbitration mechanism
	 */
	enum spdk_nvme_cc_ams arb_mechanism;

	/**
	 * Maximum number of commands that the controller may launch at one time.  The
	 * value is expressed as a power of two, valid values are from 0-7, and 7 means
	 * unlimited.
	 */
	uint8_t arbitration_burst;

	/**
	 * Number of commands that may be executed from the low priority queue in each
	 * arbitration round.  This field is only valid when arb_mechanism is set to
	 * SPDK_NVME_CC_AMS_WRR (weighted round robin).
	 */
	uint8_t low_priority_weight;

	/**
	 * Number of commands that may be executed from the medium priority queue in each
	 * arbitration round.  This field is only valid when arb_mechanism is set to
	 * SPDK_NVME_CC_AMS_WRR (weighted round robin).
	 */
	uint8_t medium_priority_weight;

	/**
	 * Number of commands that may be executed from the high priority queue in each
	 * arbitration round.  This field is only valid when arb_mechanism is set to
	 * SPDK_NVME_CC_AMS_WRR (weighted round robin).
	 */
	uint8_t high_priority_weight;

	/**
	 * Keep alive timeout in milliseconds (0 = disabled).
	 *
	 * The NVMe library will set the Keep Alive Timer feature to this value and automatically
	 * send Keep Alive commands as needed.  The library user must call
	 * spdk_nvme_ctrlr_process_admin_completions() periodically to ensure Keep Alive commands
	 * are sent.
	 */
	uint32_t keep_alive_timeout_ms;

	/**
	 * Specify the retry number when there is issue with the transport
	 */
	uint8_t transport_retry_count;

	/**
	 * The queue depth of each NVMe I/O queue.
	 */
	uint32_t io_queue_size;

	/**
	 * The host NQN to use when connecting to NVMe over Fabrics controllers.
	 *
	 * Unused for local PCIe-attached NVMe devices.
	 */
	char hostnqn[SPDK_NVMF_NQN_MAX_LEN + 1];

	/**
	 * The number of requests to allocate for each NVMe I/O queue.
	 *
	 * This should be at least as large as io_queue_size.
	 *
	 * A single I/O may allocate more than one request, since splitting may be necessary to
	 * conform to the device's maximum transfer size, PRP list compatibility requirements,
	 * or driver-assisted striping.
	 */
	uint32_t io_queue_requests;

	/**
	 * Source address for NVMe-oF connections.
	 * Set src_addr and src_svcid to empty strings if no source address should be
	 * specified.
	 */
	char src_addr[SPDK_NVMF_TRADDR_MAX_LEN + 1];

	/**
	 * Source service ID (port) for NVMe-oF connections.
	 * Set src_addr and src_svcid to empty strings if no source address should be
	 * specified.
	 */
	char src_svcid[SPDK_NVMF_TRSVCID_MAX_LEN + 1];

	/**
	 * The host identifier to use when connecting to controllers with 64-bit host ID support.
	 *
	 * Set to all zeroes to specify that no host ID should be provided to the controller.
	 */
	uint8_t host_id[8];

	/**
	 * The host identifier to use when connecting to controllers with extended (128-bit) host ID support.
	 *
	 * Set to all zeroes to specify that no host ID should be provided to the controller.
	 */
	uint8_t extended_host_id[16];

	/**
	 * The I/O command set to select.
	 *
	 * If the requested command set is not supported, the controller
	 * initialization process will not proceed. By default, the NVM
	 * command set is used.
	 */
	enum spdk_nvme_cc_css command_set;

	/**
	 * Admin commands timeout in milliseconds (0 = no timeout).
	 *
	 * The timeout value is used for admin commands submitted internally
	 * by the nvme driver during initialization, before the user is able
	 * to call spdk_nvme_ctrlr_register_timeout_callback(). By default,
	 * this is set to 120 seconds, users can change it in the probing
	 * callback.
	 */
	uint32_t admin_timeout_ms;

	/**
	 * It is used for TCP transport.
	 *
	 * Set to true, means having header digest for the header in the NVMe/TCP PDU
	 */
	bool header_digest;

	/**
	 * It is used for TCP transport.
	 *
	 * Set to true, means having data digest for the data in the NVMe/TCP PDU
	 */
	bool data_digest;

	/**
	 * Disable logging of requests that are completed with error status.
	 *
	 * Defaults to 'false' (errors are logged).
	 */
	bool disable_error_logging;

	/**
	 * It is used for RDMA transport
	 * Specify the transport ACK timeout. The value should be in range 0-31 where 0 means
	 * use driver-specific default value. The value is applied to each RDMA qpair
	 * and affects the time that qpair waits for transport layer acknowledgement
	 * until it retransmits a packet. The value should be chosen empirically
	 * to meet the needs of a particular application. A low value means less time
	 * the qpair waits for ACK which can increase the number of retransmissions.
	 * A large value can increase the time the connection is closed.
	 * The value of ACK timeout is calculated according to the formula
	 * 4.096 * 2^(transport_ack_timeout) usec.
	 */
	uint8_t transport_ack_timeout;

	/**
	 * The queue depth of NVMe Admin queue.
	 */
	uint16_t admin_queue_size;

	/**
	 * The size of spdk_nvme_ctrlr_opts according to the caller of this library is used for ABI
	 * compatibility.  The library uses this field to know how many fields in this
	 * structure are valid. And the library will populate any remaining fields with default values.
	 */
	size_t opts_size;
};

/**
 * Indicate whether a ctrlr handle is associated with a Discovery controller.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return true if a discovery controller, else false.
 */
bool spdk_nvme_ctrlr_is_discovery(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the default options for the creation of a specific NVMe controller.
 *
 * \param[out] opts Will be filled with the default option.
 * \param opts_size Must be set to sizeof(struct spdk_nvme_ctrlr_opts).
 */
void spdk_nvme_ctrlr_get_default_ctrlr_opts(struct spdk_nvme_ctrlr_opts *opts,
		size_t opts_size);

/**
 * Reason for qpair disconnect at the transport layer.
 *
 * NONE implies that the qpair is still connected while UNKNOWN means that the
 * qpair is disconnected, but the cause was not apparent.
 */
enum spdk_nvme_qp_failure_reason {
	SPDK_NVME_QPAIR_FAILURE_NONE = 0,
	SPDK_NVME_QPAIR_FAILURE_LOCAL,
	SPDK_NVME_QPAIR_FAILURE_REMOTE,
	SPDK_NVME_QPAIR_FAILURE_UNKNOWN,
};

typedef enum spdk_nvme_qp_failure_reason spdk_nvme_qp_failure_reason;

/**
 * NVMe library transports
 *
 * NOTE: These are mapped directly to the NVMe over Fabrics TRTYPE values, except for PCIe,
 * which is a special case since NVMe over Fabrics does not define a TRTYPE for local PCIe.
 *
 * Currently, this uses 256 for PCIe which is intentionally outside of the 8-bit range of TRTYPE.
 * If the NVMe-oF specification ever defines a PCIe TRTYPE, this should be updated.
 */
enum spdk_nvme_transport_type {
	/**
	 * PCIe Transport (locally attached devices)
	 */
	SPDK_NVME_TRANSPORT_PCIE = 256,

	/**
	 * RDMA Transport (RoCE, iWARP, etc.)
	 */
	SPDK_NVME_TRANSPORT_RDMA = SPDK_NVMF_TRTYPE_RDMA,

	/**
	 * Fibre Channel (FC) Transport
	 */
	SPDK_NVME_TRANSPORT_FC = SPDK_NVMF_TRTYPE_FC,

	/**
	 * TCP Transport
	 */
	SPDK_NVME_TRANSPORT_TCP = SPDK_NVMF_TRTYPE_TCP,

	/**
	 * Custom Transport (Not spec defined)
	 */
	SPDK_NVME_TRANSPORT_CUSTOM = 4096,
};

/* typedef added for coding style reasons */
typedef enum spdk_nvme_transport_type spdk_nvme_transport_type_t;

/**
 * NVMe transport identifier.
 *
 * This identifies a unique endpoint on an NVMe fabric.
 *
 * A string representation of a transport ID may be converted to this type using
 * spdk_nvme_transport_id_parse().
 */
struct spdk_nvme_transport_id {
	/**
	 * NVMe transport string.
	 */
	char trstring[SPDK_NVMF_TRSTRING_MAX_LEN + 1];

	/**
	 * NVMe transport type.
	 */
	enum spdk_nvme_transport_type trtype;

	/**
	 * Address family of the transport address.
	 *
	 * For PCIe, this value is ignored.
	 */
	enum spdk_nvmf_adrfam adrfam;

	/**
	 * Transport address of the NVMe-oF endpoint. For transports which use IP
	 * addressing (e.g. RDMA), this should be an IP address. For PCIe, this
	 * can either be a zero length string (the whole bus) or a PCI address
	 * in the format DDDD:BB:DD.FF or DDDD.BB.DD.FF. For FC the string is
	 * formatted as: nn-0xWWNN:pn-0xWWPN” where WWNN is the Node_Name of the
	 * target NVMe_Port and WWPN is the N_Port_Name of the target NVMe_Port.
	 */
	char traddr[SPDK_NVMF_TRADDR_MAX_LEN + 1];

	/**
	 * Transport service id of the NVMe-oF endpoint.  For transports which use
	 * IP addressing (e.g. RDMA), this field shoud be the port number. For PCIe,
	 * and FC this is always a zero length string.
	 */
	char trsvcid[SPDK_NVMF_TRSVCID_MAX_LEN + 1];

	/**
	 * Subsystem NQN of the NVMe over Fabrics endpoint. May be a zero length string.
	 */
	char subnqn[SPDK_NVMF_NQN_MAX_LEN + 1];

	/**
	 * The Transport connection priority of the NVMe-oF endpoint. Currently this is
	 * only supported by posix based sock implementation on Kernel TCP stack. More
	 * information of this field can be found from the socket(7) man page.
	 */
	int priority;
};

/**
 * NVMe host identifier
 *
 * Used for defining the host identity for an NVMe-oF connection.
 *
 * In terms of configuration, this object can be considered a subtype of TransportID
 * Please see etc/spdk/nvmf.conf.in for more details.
 *
 * A string representation of this type may be converted to this type using
 * spdk_nvme_host_id_parse().
 */
struct spdk_nvme_host_id {
	/**
	 * Transport address to be used by the host when connecting to the NVMe-oF endpoint.
	 * May be an IP address or a zero length string for transports which
	 * use IP addressing (e.g. RDMA).
	 * For PCIe and FC this is always a zero length string.
	 */
	char hostaddr[SPDK_NVMF_TRADDR_MAX_LEN + 1];

	/**
	 * Transport service ID used by the host when connecting to the NVMe.
	 * May be a port number or a zero length string for transports which
	 * use IP addressing (e.g. RDMA).
	 * For PCIe and FC this is always a zero length string.
	 */
	char hostsvcid[SPDK_NVMF_TRSVCID_MAX_LEN + 1];
};

/*
 * Controller support flags
 *
 * Used for identifying if the controller supports these flags.
 */
enum spdk_nvme_ctrlr_flags {
	SPDK_NVME_CTRLR_SGL_SUPPORTED			= 0x1, /**< SGL is supported */
	SPDK_NVME_CTRLR_SECURITY_SEND_RECV_SUPPORTED	= 0x2, /**< security send/receive is supported */
	SPDK_NVME_CTRLR_WRR_SUPPORTED			= 0x4, /**< Weighted Round Robin is supported */
	SPDK_NVME_CTRLR_COMPARE_AND_WRITE_SUPPORTED	= 0x8, /**< Compare and write fused operations supported */
	SPDK_NVME_CTRLR_SGL_REQUIRES_DWORD_ALIGNMENT	= 0x10, /**< Dword alignment is required for SGL */
};

/**
 * Parse the string representation of a transport ID.
 *
 * \param trid Output transport ID structure (must be allocated and initialized by caller).
 * \param str Input string representation of a transport ID to parse.
 *
 * str must be a zero-terminated C string containing one or more key:value pairs
 * separated by whitespace.
 *
 * Key          | Value
 * ------------ | -----
 * trtype       | Transport type (e.g. PCIe, RDMA)
 * adrfam       | Address family (e.g. IPv4, IPv6)
 * traddr       | Transport address (e.g. 0000:04:00.0 for PCIe, 192.168.100.8 for RDMA, or WWN for FC)
 * trsvcid      | Transport service identifier (e.g. 4420)
 * subnqn       | Subsystem NQN
 *
 * Unspecified fields of trid are left unmodified, so the caller must initialize
 * trid (for example, memset() to 0) before calling this function.
 *
 * \return 0 if parsing was successful and trid is filled out, or negated errno
 * values on failure.
 */
int spdk_nvme_transport_id_parse(struct spdk_nvme_transport_id *trid, const char *str);


/**
 * Fill in the trtype and trstring fields of this trid based on a known transport type.
 *
 * \param trid The trid to fill out.
 * \param trtype The transport type to use for filling the trid fields. Only valid for
 * transport types referenced in the NVMe-oF spec.
 */
void spdk_nvme_trid_populate_transport(struct spdk_nvme_transport_id *trid,
				       enum spdk_nvme_transport_type trtype);

/**
 * Parse the string representation of a host ID.
 *
 * \param hostid Output host ID structure (must be allocated and initialized by caller).
 * \param str Input string representation of a transport ID to parse (hostid is a sub-configuration).
 *
 * str must be a zero-terminated C string containing one or more key:value pairs
 * separated by whitespace.
 *
 * Key            | Value
 * -------------- | -----
 * hostaddr       | Transport address (e.g. 192.168.100.8 for RDMA)
 * hostsvcid      | Transport service identifier (e.g. 4420)
 *
 * Unspecified fields of trid are left unmodified, so the caller must initialize
 * hostid (for example, memset() to 0) before calling this function.
 *
 * This function should not be used with Fiber Channel or PCIe as these transports
 * do not require host information for connections.
 *
 * \return 0 if parsing was successful and hostid is filled out, or negated errno
 * values on failure.
 */
int spdk_nvme_host_id_parse(struct spdk_nvme_host_id *hostid, const char *str);

/**
 * Parse the string representation of a transport ID tranport type into the trid struct.
 *
 * \param trid The trid to write to
 * \param trstring Input string representation of transport type (e.g. "PCIe", "RDMA").
 *
 * \return 0 if parsing was successful and trtype is filled out, or negated errno
 * values if the provided string was an invalid transport string.
 */
int spdk_nvme_transport_id_populate_trstring(struct spdk_nvme_transport_id *trid,
		const char *trstring);

/**
 * Parse the string representation of a transport ID tranport type.
 *
 * \param trtype Output transport type (allocated by caller).
 * \param str Input string representation of transport type (e.g. "PCIe", "RDMA").
 *
 * \return 0 if parsing was successful and trtype is filled out, or negated errno
 * values on failure.
 */
int spdk_nvme_transport_id_parse_trtype(enum spdk_nvme_transport_type *trtype, const char *str);

/**
 * Look up the string representation of a transport ID transport type.
 *
 * \param trtype Transport type to convert.
 *
 * \return static string constant describing trtype, or NULL if trtype not found.
 */
const char *spdk_nvme_transport_id_trtype_str(enum spdk_nvme_transport_type trtype);

/**
 * Look up the string representation of a transport ID address family.
 *
 * \param adrfam Address family to convert.
 *
 * \return static string constant describing adrfam, or NULL if adrmfam not found.
 */
const char *spdk_nvme_transport_id_adrfam_str(enum spdk_nvmf_adrfam adrfam);

/**
 * Parse the string representation of a tranport ID address family.
 *
 * \param adrfam Output address family (allocated by caller).
 * \param str Input string representation of address family (e.g. "IPv4", "IPv6").
 *
 * \return 0 if parsing was successful and adrfam is filled out, or negated errno
 * values on failure.
 */
int spdk_nvme_transport_id_parse_adrfam(enum spdk_nvmf_adrfam *adrfam, const char *str);

/**
 * Compare two transport IDs.
 *
 * The result of this function may be used to sort transport IDs in a consistent
 * order; however, the comparison result is not guaranteed to be consistent across
 * library versions.
 *
 * This function uses a case-insensitive comparison for string fields, but it does
 * not otherwise normalize the transport ID. It is the caller's responsibility to
 * provide the transport IDs in a consistent format.
 *
 * \param trid1 First transport ID to compare.
 * \param trid2 Second transport ID to compare.
 *
 * \return 0 if trid1 == trid2, less than 0 if trid1 < trid2, greater than 0 if
 * trid1 > trid2.
 */
int spdk_nvme_transport_id_compare(const struct spdk_nvme_transport_id *trid1,
				   const struct spdk_nvme_transport_id *trid2);

/**
 * Parse the string representation of PI check settings (prchk:guard|reftag)
 *
 * \param prchk_flags Output PI check flags.
 * \param str Input string representation of PI check settings.
 *
 * \return 0 if parsing was successful and prchk_flags is set, or negated errno
 * values on failure.
 */
int spdk_nvme_prchk_flags_parse(uint32_t *prchk_flags, const char *str);

/**
 * Look up the string representation of PI check settings  (prchk:guard|reftag)
 *
 * \param prchk_flags PI check flags to convert.
 *
 * \return static string constant describing PI check settings. If prchk_flags is 0,
 * NULL is returned.
 */
const char *spdk_nvme_prchk_flags_str(uint32_t prchk_flags);

/**
 * Determine whether the NVMe library can handle a specific NVMe over Fabrics
 * transport type.
 *
 * \param trtype NVMe over Fabrics transport type to check.
 *
 * \return true if trtype is supported or false if it is not supported or if
 * SPDK_NVME_TRANSPORT_CUSTOM is supplied as trtype since it can represent multiple
 * transports.
 */
bool spdk_nvme_transport_available(enum spdk_nvme_transport_type trtype);

/**
 * Determine whether the NVMe library can handle a specific NVMe over Fabrics
 * transport type.
 *
 * \param transport_name Name of the NVMe over Fabrics transport type to check.
 *
 * \return true if transport_name is supported or false if it is not supported.
 */
bool spdk_nvme_transport_available_by_name(const char *transport_name);

/**
 * Callback for spdk_nvme_probe() enumeration.
 *
 * \param cb_ctx Opaque value passed to spdk_nvme_probe().
 * \param trid NVMe transport identifier.
 * \param opts NVMe controller initialization options. This structure will be
 * populated with the default values on entry, and the user callback may update
 * any options to request a different value. The controller may not support all
 * requested parameters, so the final values will be provided during the attach
 * callback.
 *
 * \return true to attach to this device.
 */
typedef bool (*spdk_nvme_probe_cb)(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
				   struct spdk_nvme_ctrlr_opts *opts);

/**
 * Callback for spdk_nvme_attach() to report a device that has been attached to
 * the userspace NVMe driver.
 *
 * \param cb_ctx Opaque value passed to spdk_nvme_attach_cb().
 * \param trid NVMe transport identifier.
 * \param ctrlr Opaque handle to NVMe controller.
 * \param opts NVMe controller initialization options that were actually used.
 * Options may differ from the requested options from the attach call depending
 * on what the controller supports.
 */
typedef void (*spdk_nvme_attach_cb)(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
				    struct spdk_nvme_ctrlr *ctrlr,
				    const struct spdk_nvme_ctrlr_opts *opts);

/**
 * Callback for spdk_nvme_remove() to report that a device attached to the userspace
 * NVMe driver has been removed from the system.
 *
 * The controller will remain in a failed state (any new I/O submitted will fail).
 *
 * The controller must be detached from the userspace driver by calling spdk_nvme_detach()
 * once the controller is no longer in use. It is up to the library user to ensure
 * that no other threads are using the controller before calling spdk_nvme_detach().
 *
 * \param cb_ctx Opaque value passed to spdk_nvme_remove_cb().
 * \param ctrlr NVMe controller instance that was removed.
 */
typedef void (*spdk_nvme_remove_cb)(void *cb_ctx, struct spdk_nvme_ctrlr *ctrlr);

/**
 * Enumerate the bus indicated by the transport ID and attach the userspace NVMe
 * driver to each device found if desired.
 *
 * This function is not thread safe and should only be called from one thread at
 * a time while no other threads are actively using any NVMe devices.
 *
 * If called from a secondary process, only devices that have been attached to
 * the userspace driver in the primary process will be probed.
 *
 * If called more than once, only devices that are not already attached to the
 * SPDK NVMe driver will be reported.
 *
 * To stop using the the controller and release its associated resources,
 * call spdk_nvme_detach() with the spdk_nvme_ctrlr instance from the attach_cb()
 * function.
 *
 * \param trid The transport ID indicating which bus to enumerate. If the trtype
 * is PCIe or trid is NULL, this will scan the local PCIe bus. If the trtype is
 * RDMA, the traddr and trsvcid must point at the location of an NVMe-oF discovery
 * service.
 * \param cb_ctx Opaque value which will be passed back in cb_ctx parameter of
 * the callbacks.
 * \param probe_cb will be called once per NVMe device found in the system.
 * \param attach_cb will be called for devices for which probe_cb returned true
 * once that NVMe controller has been attached to the userspace driver.
 * \param remove_cb will be called for devices that were attached in a previous
 * spdk_nvme_probe() call but are no longer attached to the system. Optional;
 * specify NULL if removal notices are not desired.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_nvme_probe(const struct spdk_nvme_transport_id *trid,
		    void *cb_ctx,
		    spdk_nvme_probe_cb probe_cb,
		    spdk_nvme_attach_cb attach_cb,
		    spdk_nvme_remove_cb remove_cb);

/**
 * Connect the NVMe driver to the device located at the given transport ID.
 *
 * This function is not thread safe and should only be called from one thread at
 * a time while no other threads are actively using this NVMe device.
 *
 * If called from a secondary process, only the device that has been attached to
 * the userspace driver in the primary process will be connected.
 *
 * If connecting to multiple controllers, it is suggested to use spdk_nvme_probe()
 * and filter the requested controllers with the probe callback. For PCIe controllers,
 * spdk_nvme_probe() will be more efficient since the controller resets will happen
 * in parallel.
 *
 * To stop using the the controller and release its associated resources, call
 * spdk_nvme_detach() with the spdk_nvme_ctrlr instance returned by this function.
 *
 * \param trid The transport ID indicating which device to connect. If the trtype
 * is PCIe, this will connect the local PCIe bus. If the trtype is RDMA, the traddr
 * and trsvcid must point at the location of an NVMe-oF service.
 * \param opts NVMe controller initialization options. Default values will be used
 * if the user does not specify the options. The controller may not support all
 * requested parameters.
 * \param opts_size Must be set to sizeof(struct spdk_nvme_ctrlr_opts), or 0 if
 * opts is NULL.
 *
 * \return pointer to the connected NVMe controller or NULL if there is any failure.
 *
 */
struct spdk_nvme_ctrlr *spdk_nvme_connect(const struct spdk_nvme_transport_id *trid,
		const struct spdk_nvme_ctrlr_opts *opts,
		size_t opts_size);

struct spdk_nvme_probe_ctx;

/**
 * Connect the NVMe driver to the device located at the given transport ID.
 *
 * The function will return a probe context on success, controller associates with
 * the context is not ready for use, user must call spdk_nvme_probe_poll_async()
 * until spdk_nvme_probe_poll_async() returns 0.
 *
 * \param trid The transport ID indicating which device to connect. If the trtype
 * is PCIe, this will connect the local PCIe bus. If the trtype is RDMA, the traddr
 * and trsvcid must point at the location of an NVMe-oF service.
 * \param opts NVMe controller initialization options. Default values will be used
 * if the user does not specify the options. The controller may not support all
 * requested parameters.
 * \param attach_cb will be called once the NVMe controller has been attached
 * to the userspace driver.
 *
 * \return probe context on success, NULL on failure.
 *
 */
struct spdk_nvme_probe_ctx *spdk_nvme_connect_async(const struct spdk_nvme_transport_id *trid,
		const struct spdk_nvme_ctrlr_opts *opts,
		spdk_nvme_attach_cb attach_cb);

/**
 * Probe and add controllers to the probe context list.
 *
 * Users must call spdk_nvme_probe_poll_async() to initialize
 * controllers in the probe context list to the READY state.
 *
 * \param trid The transport ID indicating which bus to enumerate. If the trtype
 * is PCIe or trid is NULL, this will scan the local PCIe bus. If the trtype is
 * RDMA, the traddr and trsvcid must point at the location of an NVMe-oF discovery
 * service.
 * \param cb_ctx Opaque value which will be passed back in cb_ctx parameter of
 * the callbacks.
 * \param probe_cb will be called once per NVMe device found in the system.
 * \param attach_cb will be called for devices for which probe_cb returned true
 * once that NVMe controller has been attached to the userspace driver.
 * \param remove_cb will be called for devices that were attached in a previous
 * spdk_nvme_probe() call but are no longer attached to the system. Optional;
 * specify NULL if removal notices are not desired.
 *
 * \return probe context on success, NULL on failure.
 */
struct spdk_nvme_probe_ctx *spdk_nvme_probe_async(const struct spdk_nvme_transport_id *trid,
		void *cb_ctx,
		spdk_nvme_probe_cb probe_cb,
		spdk_nvme_attach_cb attach_cb,
		spdk_nvme_remove_cb remove_cb);

/**
 * Start controllers in the context list.
 *
 * Users may call the function util it returns True.
 *
 * \param probe_ctx Context used to track probe actions.
 *
 * \return 0 if all probe operations are complete; the probe_ctx
 * is also freed and no longer valid.
 * \return -EAGAIN if there are still pending probe operations; user must call
 * spdk_nvme_probe_poll_async again to continue progress.
 * \return value other than 0 and -EAGAIN probe error with one controller.
 */
int spdk_nvme_probe_poll_async(struct spdk_nvme_probe_ctx *probe_ctx);

/**
 * Detach specified device returned by spdk_nvme_probe()'s attach_cb from the
 * NVMe driver.
 *
 * On success, the spdk_nvme_ctrlr handle is no longer valid.
 *
 * This function should be called from a single thread while no other threads
 * are actively using the NVMe device.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_nvme_detach(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Update the transport ID for a given controller.
 *
 * This function allows the user to set a new trid for a controller only if the
 * controller is failed. The controller's failed state can be obtained from
 * spdk_nvme_ctrlr_is_failed(). The controller can also be forced to the failed
 * state using spdk_nvme_ctrlr_fail().
 *
 * This function also requires that the transport type and subnqn of the new trid
 * be the same as the old trid.
 *
 * \param ctrlr Opaque handle to an NVMe controller.
 * \param trid The new transport ID.
 *
 * \return 0 on success, -EINVAL if the trid is invalid,
 * -EPERM if the ctrlr is not failed.
 */
int spdk_nvme_ctrlr_set_trid(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_transport_id *trid);

/**
 * Perform a full hardware reset of the NVMe controller.
 *
 * This function should be called from a single thread while no other threads
 * are actively using the NVMe device.
 *
 * Any pointers returned from spdk_nvme_ctrlr_get_ns() and spdk_nvme_ns_get_data()
 * may be invalidated by calling this function. The number of namespaces as returned
 * by spdk_nvme_ctrlr_get_num_ns() may also change.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_nvme_ctrlr_reset(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Fail the given NVMe controller.
 *
 * This function gives the application the opportunity to fail a controller
 * at will. When a controller is failed, any calls to process completions or
 * submit I/O on qpairs associated with that controller will fail with an error
 * code of -ENXIO.
 * The controller can only be taken from the failed state by
 * calling spdk_nvme_ctrlr_reset. After the controller has been successfully
 * reset, any I/O pending when the controller was moved to failed will be
 * aborted back to the application and can be resubmitted. I/O can then resume.
 *
 * \param ctrlr Opaque handle to an NVMe controller.
 */
void spdk_nvme_ctrlr_fail(struct spdk_nvme_ctrlr *ctrlr);

/**
 * This function returns the failed status of a given controller.
 *
 * \param ctrlr Opaque handle to an NVMe controller.
 *
 * \return True if the controller is failed, false otherwise.
 */
bool spdk_nvme_ctrlr_is_failed(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the identify controller data as defined by the NVMe specification.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return pointer to the identify controller data.
 */
const struct spdk_nvme_ctrlr_data *spdk_nvme_ctrlr_get_data(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the NVMe controller CSTS (Status) register.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return the NVMe controller CSTS (Status) register.
 */
union spdk_nvme_csts_register spdk_nvme_ctrlr_get_regs_csts(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the NVMe controller CAP (Capabilities) register.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return the NVMe controller CAP (Capabilities) register.
 */
union spdk_nvme_cap_register spdk_nvme_ctrlr_get_regs_cap(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the NVMe controller VS (Version) register.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return the NVMe controller VS (Version) register.
 */
union spdk_nvme_vs_register spdk_nvme_ctrlr_get_regs_vs(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the NVMe controller CMBSZ (Controller Memory Buffer Size) register
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return the NVMe controller CMBSZ (Controller Memory Buffer Size) register.
 */
union spdk_nvme_cmbsz_register spdk_nvme_ctrlr_get_regs_cmbsz(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the number of namespaces for the given NVMe controller.
 *
 * This function is thread safe and can be called at any point while the
 * controller is attached to the SPDK NVMe driver.
 *
 * This is equivalent to calling spdk_nvme_ctrlr_get_data() to get the
 * spdk_nvme_ctrlr_data and then reading the nn field.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return the number of namespaces.
 */
uint32_t spdk_nvme_ctrlr_get_num_ns(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the PCI device of a given NVMe controller.
 *
 * This only works for local (PCIe-attached) NVMe controllers; other transports
 * will return NULL.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return PCI device of the NVMe controller, or NULL if not available.
 */
struct spdk_pci_device *spdk_nvme_ctrlr_get_pci_device(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the maximum data transfer size of a given NVMe controller.
 *
 * \return Maximum data transfer size of the NVMe controller in bytes.
 *
 * The I/O command helper functions, such as spdk_nvme_ns_cmd_read(), will split
 * large I/Os automatically; however, it is up to the user to obey this limit for
 * commands submitted with the raw command functions, such as spdk_nvme_ctrlr_cmd_io_raw().
 */
uint32_t spdk_nvme_ctrlr_get_max_xfer_size(const struct spdk_nvme_ctrlr *ctrlr);

/**
 * Check whether the nsid is an active nv for the given NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param nsid Namespace id.
 *
 * \return true if nsid is an active ns, or false otherwise.
 */
bool spdk_nvme_ctrlr_is_active_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid);

/**
 * Get the nsid of the first active namespace.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return the nsid of the first active namespace, 0 if there are no active namespaces.
 */
uint32_t spdk_nvme_ctrlr_get_first_active_ns(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get next active namespace given the previous nsid.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param prev_nsid Namespace id.
 *
 * \return a next active namespace given the previous nsid, 0 when there are no
 * more active namespaces.
 */
uint32_t spdk_nvme_ctrlr_get_next_active_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t prev_nsid);

/**
 * Determine if a particular log page is supported by the given NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \sa spdk_nvme_ctrlr_cmd_get_log_page().
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param log_page Log page to query.
 *
 * \return true if supported, or false otherwise.
 */
bool spdk_nvme_ctrlr_is_log_page_supported(struct spdk_nvme_ctrlr *ctrlr, uint8_t log_page);

/**
 * Determine if a particular feature is supported by the given NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \sa spdk_nvme_ctrlr_cmd_get_feature().
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param feature_code Feature to query.
 *
 * \return true if supported, or false otherwise.
 */
bool spdk_nvme_ctrlr_is_feature_supported(struct spdk_nvme_ctrlr *ctrlr, uint8_t feature_code);

/**
 * Signature for callback function invoked when a command is completed.
 *
 * \param spdk_nvme_cpl Completion queue entry that coontains the completion status.
 */
typedef void (*spdk_nvme_cmd_cb)(void *, const struct spdk_nvme_cpl *);

/**
 * Signature for callback function invoked when an asynchronous error request
 * command is completed.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param aer_cb_arg Context specified by spdk_nvme_register_aer_callback().
 * \param spdk_nvme_cpl Completion queue entry that contains the completion status
 * of the asynchronous event request that was completed.
 */
typedef void (*spdk_nvme_aer_cb)(void *aer_cb_arg,
				 const struct spdk_nvme_cpl *);

/**
 * Register callback function invoked when an AER command is completed for the
 * given NVMe controller.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param aer_cb_fn Callback function invoked when an asynchronous error request
 * command is completed.
 * \param aer_cb_arg Argument passed to callback function.
 */
void spdk_nvme_ctrlr_register_aer_callback(struct spdk_nvme_ctrlr *ctrlr,
		spdk_nvme_aer_cb aer_cb_fn,
		void *aer_cb_arg);

/**
 * Opaque handle to a queue pair.
 *
 * I/O queue pairs may be allocated using spdk_nvme_ctrlr_alloc_io_qpair().
 */
struct spdk_nvme_qpair;

/**
 * Signature for the callback function invoked when a timeout is detected on a
 * request.
 *
 * For timeouts detected on the admin queue pair, the qpair returned here will
 * be NULL.  If the controller has a serious error condition and is unable to
 * communicate with driver via completion queue, the controller can set Controller
 * Fatal Status field to 1, then reset is required to recover from such error.
 * Users may detect Controller Fatal Status when timeout happens.
 *
 * \param cb_arg Argument passed to callback funciton.
 * \param ctrlr Opaque handle to NVMe controller.
 * \param qpair Opaque handle to a queue pair.
 * \param cid Command ID.
 */
typedef void (*spdk_nvme_timeout_cb)(void *cb_arg,
				     struct spdk_nvme_ctrlr *ctrlr,
				     struct spdk_nvme_qpair *qpair,
				     uint16_t cid);

/**
 * Register for timeout callback on a controller.
 *
 * The application can choose to register for timeout callback or not register
 * for timeout callback.
 *
 * \param ctrlr NVMe controller on which to monitor for timeout.
 * \param timeout_us Timeout value in microseconds.
 * \param cb_fn A function pointer that points to the callback function.
 * \param cb_arg Argument to the callback function.
 */
void spdk_nvme_ctrlr_register_timeout_callback(struct spdk_nvme_ctrlr *ctrlr,
		uint64_t timeout_us, spdk_nvme_timeout_cb cb_fn, void *cb_arg);

/**
 * NVMe I/O queue pair initialization options.
 *
 * These options may be passed to spdk_nvme_ctrlr_alloc_io_qpair() to configure queue pair
 * options at queue creation time.
 *
 * The user may retrieve the default I/O queue pair creation options for a controller using
 * spdk_nvme_ctrlr_get_default_io_qpair_opts().
 */
struct spdk_nvme_io_qpair_opts {
	/**
	 * Queue priority for weighted round robin arbitration.  If a different arbitration
	 * method is in use, pass 0.
	 */
	enum spdk_nvme_qprio qprio;

	/**
	 * The queue depth of this NVMe I/O queue. Overrides spdk_nvme_ctrlr_opts::io_queue_size.
	 */
	uint32_t io_queue_size;

	/**
	 * The number of requests to allocate for this NVMe I/O queue.
	 *
	 * Overrides spdk_nvme_ctrlr_opts::io_queue_requests.
	 *
	 * This should be at least as large as io_queue_size.
	 *
	 * A single I/O may allocate more than one request, since splitting may be
	 * necessary to conform to the device's maximum transfer size, PRP list
	 * compatibility requirements, or driver-assisted striping.
	 */
	uint32_t io_queue_requests;

	/**
	 * When submitting I/O via spdk_nvme_ns_read/write and similar functions,
	 * don't immediately submit it to hardware. Instead, queue up new commands
	 * and submit them to the hardware inside spdk_nvme_qpair_process_completions().
	 *
	 * This results in better batching of I/O commands. Often, it is more efficient
	 * to submit batches of commands to the underlying hardware than each command
	 * individually.
	 *
	 * This only applies to PCIe and RDMA transports.
	 *
	 * The flag was originally named delay_pcie_doorbell. To allow backward compatibility
	 * both names are kept in unnamed union.
	 */
	union {
		bool delay_cmd_submit;
		bool delay_pcie_doorbell;
	};

	/**
	 * These fields allow specifying the memory buffers for the submission and/or
	 * completion queues.
	 * By default, vaddr is set to NULL meaning SPDK will allocate the memory to be used.
	 * If vaddr is NULL then paddr must be set to 0.
	 * If vaddr is non-NULL, and paddr is zero, SPDK derives the physical
	 * address for the NVMe device, in this case the memory must be registered.
	 * If a paddr value is non-zero, SPDK uses the vaddr and paddr as passed
	 * SPDK assumes that the memory passed is both virtually and physically
	 * contiguous.
	 * If these fields are used, SPDK will NOT impose any restriction
	 * on the number of elements in the queues.
	 * The buffer sizes are in number of bytes, and are used to confirm
	 * that the buffers are large enough to contain the appropriate queue.
	 * These fields are only used by PCIe attached NVMe devices.  They
	 * are presently ignored for other transports.
	 */
	struct {
		struct spdk_nvme_cmd *vaddr;
		uint64_t paddr;
		uint64_t buffer_size;
	} sq;
	struct {
		struct spdk_nvme_cpl *vaddr;
		uint64_t paddr;
		uint64_t buffer_size;
	} cq;

	/**
	 * This flag indicates to the alloc_io_qpair function that it should not perform
	 * the connect portion on this qpair. This allows the user to add the qpair to a
	 * poll group and then connect it later.
	 */
	bool create_only;
};

/**
 * Get the default options for I/O qpair creation for a specific NVMe controller.
 *
 * \param ctrlr NVMe controller to retrieve the defaults from.
 * \param[out] opts Will be filled with the default options for
 * spdk_nvme_ctrlr_alloc_io_qpair().
 * \param opts_size Must be set to sizeof(struct spdk_nvme_io_qpair_opts).
 */
void spdk_nvme_ctrlr_get_default_io_qpair_opts(struct spdk_nvme_ctrlr *ctrlr,
		struct spdk_nvme_io_qpair_opts *opts,
		size_t opts_size);

/**
 * Allocate an I/O queue pair (submission and completion queue).
 *
 * This function by default also performs any connection activities required for
 * a newly created qpair. To avoid that behavior, the user should set the create_only
 * flag in the opts structure to true.
 *
 * Each queue pair should only be used from a single thread at a time (mutual
 * exclusion must be enforced by the user).
 *
 * \param ctrlr NVMe controller for which to allocate the I/O queue pair.
 * \param opts I/O qpair creation options, or NULL to use the defaults as returned
 * by spdk_nvme_ctrlr_get_default_io_qpair_opts().
 * \param opts_size Must be set to sizeof(struct spdk_nvme_io_qpair_opts), or 0
 * if opts is NULL.
 *
 * \return a pointer to the allocated I/O queue pair.
 */
struct spdk_nvme_qpair *spdk_nvme_ctrlr_alloc_io_qpair(struct spdk_nvme_ctrlr *ctrlr,
		const struct spdk_nvme_io_qpair_opts *opts,
		size_t opts_size);

/**
 * Connect a newly created I/O qpair.
 *
 * This function does any connection activities required for a newly created qpair.
 * It should be called after spdk_nvme_ctrlr_alloc_io_qpair has been called with the
 * create_only flag set to true in the spdk_nvme_io_qpair_opts structure.
 *
 * This call will fail if performed on a qpair that is already connected.
 * For reconnecting qpairs, see spdk_nvme_ctrlr_reconnect_io_qpair.
 *
 * For fabrics like TCP and RDMA, this function actually sends the commands over the wire
 * that connect the qpair. For PCIe, this function performs some internal state machine operations.
 *
 * \param ctrlr NVMe controller for which to allocate the I/O queue pair.
 * \param qpair Opaque handle to the qpair to connect.
 *
 * return 0 on success or negated errno on failure. Specifically -EISCONN if the qpair is already connected.
 *
 */
int spdk_nvme_ctrlr_connect_io_qpair(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_qpair *qpair);

/**
 * Disconnect the given I/O qpair.
 *
 * This function must be called from the same thread as spdk_nvme_qpair_process_completions
 * and the spdk_nvme_ns_cmd_* functions.
 *
 * After disconnect, calling spdk_nvme_qpair_process_completions or one of the
 * spdk_nvme_ns_cmd* on a qpair will result in a return value of -ENXIO. A
 * disconnected qpair may be reconnected with either the spdk_nvme_ctrlr_connect_io_qpair
 * or spdk_nvme_ctrlr_reconnect_io_qpair APIs.
 *
 * \param qpair The qpair to disconnect.
 */
void spdk_nvme_ctrlr_disconnect_io_qpair(struct spdk_nvme_qpair *qpair);

/**
 * Attempt to reconnect the given qpair.
 *
 * This function is intended to be called on qpairs that have already been connected,
 * but have since entered a failed state as indicated by a return value of -ENXIO from
 * either spdk_nvme_qpair_process_completions or one of the spdk_nvme_ns_cmd_* functions.
 * This function must be called from the same thread as spdk_nvme_qpair_process_completions
 * and the spdk_nvme_ns_cmd_* functions.
 *
 * Calling this function has the same effect as calling spdk_nvme_ctrlr_disconnect_io_qpair
 * followed by spdk_nvme_ctrlr_connect_io_qpair.
 *
 * This function may be called on newly created qpairs, but it does extra checks and attempts
 * to disconnect the qpair before connecting it. The recommended API for newly created qpairs
 * is spdk_nvme_ctrlr_connect_io_qpair.
 *
 * \param qpair The qpair to reconnect.
 *
 * \return 0 on success, or if the qpair was already connected.
 * -EAGAIN if the driver was unable to reconnect during this call,
 * but the controller is still connected and is either resetting or enabled.
 * -ENODEV if the controller is removed. In this case, the controller cannot be recovered
 * and the application will have to destroy it and the associated qpairs.
 * -ENXIO if the controller is in a failed state but is not yet resetting. In this case,
 * the application should call spdk_nvme_ctrlr_reset to reset the entire controller.
 */
int spdk_nvme_ctrlr_reconnect_io_qpair(struct spdk_nvme_qpair *qpair);

/**
 * Returns the reason the admin qpair for a given controller is disconnected.
 *
 * \param ctrlr The controller to check.
 *
 * \return a valid spdk_nvme_qp_failure_reason.
 */
spdk_nvme_qp_failure_reason spdk_nvme_ctrlr_get_admin_qp_failure_reason(
	struct spdk_nvme_ctrlr *ctrlr);

/**
 * Free an I/O queue pair that was allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 *
 * \param qpair I/O queue pair to free.
 *
 * \return 0 on success, -1 on failure.
 */
int spdk_nvme_ctrlr_free_io_qpair(struct spdk_nvme_qpair *qpair);

/**
 * Send the given NVM I/O command, I/O buffers, lists and all to the NVMe controller.
 *
 * This is a low level interface for submitting I/O commands directly.
 *
 * This function allows a caller to submit an I/O request that is
 * COMPLETELY pre-defined, right down to the "physical" memory buffers.
 * It is intended for testing hardware, specifying exact buffer location,
 * alignment, and offset.  It also allows for specific choice of PRP
 * and SGLs.
 *
 * The driver sets the CID.  EVERYTHING else is assumed set by the caller.
 * Needless to say, this is potentially extremely dangerous for both the host
 * (accidental/malicionus storage usage/corruption), and the device.
 * Thus its intent is for very specific hardware testing and environment
 * reproduction.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * This function can only be used on PCIe controllers and qpairs.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param qpair I/O qpair to submit command.
 * \param cmd NVM I/O command to submit.
 * \param cb_fn Callback function invoked when the I/O command completes.
 * \param cb_arg Argument passed to callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 */

int spdk_nvme_ctrlr_io_cmd_raw_no_payload_build(struct spdk_nvme_ctrlr *ctrlr,
		struct spdk_nvme_qpair *qpair,
		struct spdk_nvme_cmd *cmd,
		spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Send the given NVM I/O command to the NVMe controller.
 *
 * This is a low level interface for submitting I/O commands directly. Prefer
 * the spdk_nvme_ns_cmd_* functions instead. The validity of the command will
 * not be checked!
 *
 * When constructing the nvme_command it is not necessary to fill out the PRP
 * list/SGL or the CID. The driver will handle both of those for you.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param qpair I/O qpair to submit command.
 * \param cmd NVM I/O command to submit.
 * \param buf Virtual memory address of a single physically contiguous buffer.
 * \param len Size of buffer.
 * \param cb_fn Callback function invoked when the I/O command completes.
 * \param cb_arg Argument passed to callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ctrlr_cmd_io_raw(struct spdk_nvme_ctrlr *ctrlr,
			       struct spdk_nvme_qpair *qpair,
			       struct spdk_nvme_cmd *cmd,
			       void *buf, uint32_t len,
			       spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Send the given NVM I/O command with metadata to the NVMe controller.
 *
 * This is a low level interface for submitting I/O commands directly. Prefer
 * the spdk_nvme_ns_cmd_* functions instead. The validity of the command will
 * not be checked!
 *
 * When constructing the nvme_command it is not necessary to fill out the PRP
 * list/SGL or the CID. The driver will handle both of those for you.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param qpair I/O qpair to submit command.
 * \param cmd NVM I/O command to submit.
 * \param buf Virtual memory address of a single physically contiguous buffer.
 * \param len Size of buffer.
 * \param md_buf Virtual memory address of a single physically contiguous metadata
 * buffer.
 * \param cb_fn Callback function invoked when the I/O command completes.
 * \param cb_arg Argument passed to callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ctrlr_cmd_io_raw_with_md(struct spdk_nvme_ctrlr *ctrlr,
				       struct spdk_nvme_qpair *qpair,
				       struct spdk_nvme_cmd *cmd,
				       void *buf, uint32_t len, void *md_buf,
				       spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Process any outstanding completions for I/O submitted on a queue pair.
 *
 * This call is non-blocking, i.e. it only processes completions that are ready
 * at the time of this function call. It does not wait for outstanding commands
 * to finish.
 *
 * For each completed command, the request's callback function will be called if
 * specified as non-NULL when the request was submitted.
 *
 * The caller must ensure that each queue pair is only used from one thread at a
 * time.
 *
 * This function may be called at any point while the controller is attached to
 * the SPDK NVMe driver.
 *
 * \sa spdk_nvme_cmd_cb
 *
 * \param qpair Queue pair to check for completions.
 * \param max_completions Limit the number of completions to be processed in one
 * call, or 0 for unlimited.
 *
 * \return number of completions processed (may be 0) or negated on error. -ENXIO
 * in the special case that the qpair is failed at the transport layer.
 */
int32_t spdk_nvme_qpair_process_completions(struct spdk_nvme_qpair *qpair,
		uint32_t max_completions);

/**
 * Returns the reason the qpair is disconnected.
 *
 * \param qpair The qpair to check.
 *
 * \return a valid spdk_nvme_qp_failure_reason.
 */
spdk_nvme_qp_failure_reason spdk_nvme_qpair_get_failure_reason(struct spdk_nvme_qpair *qpair);

/**
 * Send the given admin command to the NVMe controller.
 *
 * This is a low level interface for submitting admin commands directly. Prefer
 * the spdk_nvme_ctrlr_cmd_* functions instead. The validity of the command will
 * not be checked!
 *
 * When constructing the nvme_command it is not necessary to fill out the PRP
 * list/SGL or the CID. The driver will handle both of those for you.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion
 * of commands submitted through this function.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param cmd NVM admin command to submit.
 * \param buf Virtual memory address of a single physically contiguous buffer.
 * \param len Size of buffer.
 * \param cb_fn Callback function invoked when the admin command completes.
 * \param cb_arg Argument passed to callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated for this request, -ENXIO if the admin qpair is failed at the transport layer.
 */
int spdk_nvme_ctrlr_cmd_admin_raw(struct spdk_nvme_ctrlr *ctrlr,
				  struct spdk_nvme_cmd *cmd,
				  void *buf, uint32_t len,
				  spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Process any outstanding completions for admin commands.
 *
 * This will process completions for admin commands submitted on any thread.
 *
 * This call is non-blocking, i.e. it only processes completions that are ready
 * at the time of this function call. It does not wait for outstanding commands
 * to finish.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 *
 * \return number of completions processed (may be 0) or negated on error. -ENXIO
 * in the special case that the qpair is failed at the transport layer.
 */
int32_t spdk_nvme_ctrlr_process_admin_completions(struct spdk_nvme_ctrlr *ctrlr);


/**
 * Opaque handle to a namespace. Obtained by calling spdk_nvme_ctrlr_get_ns().
 */
struct spdk_nvme_ns;

/**
 * Get a handle to a namespace for the given controller.
 *
 * Namespaces are numbered from 1 to the total number of namespaces. There will
 * never be any gaps in the numbering. The number of namespaces is obtained by
 * calling spdk_nvme_ctrlr_get_num_ns().
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param ns_id Namespace id.
 *
 * \return a pointer to the namespace.
 */
struct spdk_nvme_ns *spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t ns_id);

/**
 * Get a specific log page from the NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \sa spdk_nvme_ctrlr_is_log_page_supported()
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param log_page The log page identifier.
 * \param nsid Depending on the log page, this may be 0, a namespace identifier,
 * or SPDK_NVME_GLOBAL_NS_TAG.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param offset Offset in bytes within the log page to start retrieving log page
 * data. May only be non-zero if the controller supports extended data for Get Log
 * Page as reported in the controller data log page attributes.
 * \param cb_fn Callback function to invoke when the log page has been retrieved.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated for this request, -ENXIO if the admin qpair is failed at the transport layer.
 */
int spdk_nvme_ctrlr_cmd_get_log_page(struct spdk_nvme_ctrlr *ctrlr,
				     uint8_t log_page, uint32_t nsid,
				     void *payload, uint32_t payload_size,
				     uint64_t offset,
				     spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Get a specific log page from the NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * This function allows specifying extra fields in cdw10 and cdw11 such as
 * Retain Asynchronous Event and Log Specific Field.
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \sa spdk_nvme_ctrlr_is_log_page_supported()
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param log_page The log page identifier.
 * \param nsid Depending on the log page, this may be 0, a namespace identifier,
 * or SPDK_NVME_GLOBAL_NS_TAG.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param offset Offset in bytes within the log page to start retrieving log page
 * data. May only be non-zero if the controller supports extended data for Get Log
 * Page as reported in the controller data log page attributes.
 * \param cdw10 Value to specify for cdw10.  Specify 0 for numdl - it will be
 * set by this function based on the payload_size parameter.  Specify 0 for lid -
 * it will be set by this function based on the log_page parameter.
 * \param cdw11 Value to specify for cdw11.  Specify 0 for numdu - it will be
 * set by this function based on the payload_size.
 * \param cdw14 Value to specify for cdw14.
 * \param cb_fn Callback function to invoke when the log page has been retrieved.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated for this request, -ENXIO if the admin qpair is failed at the transport layer.
 */
int spdk_nvme_ctrlr_cmd_get_log_page_ext(struct spdk_nvme_ctrlr *ctrlr, uint8_t log_page,
		uint32_t nsid, void *payload, uint32_t payload_size,
		uint64_t offset, uint32_t cdw10, uint32_t cdw11,
		uint32_t cdw14, spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Abort a specific previously-submitted NVMe command.
 *
 * \sa spdk_nvme_ctrlr_register_timeout_callback()
 *
 * \param ctrlr NVMe controller to which the command was submitted.
 * \param qpair NVMe queue pair to which the command was submitted. For admin
 *  commands, pass NULL for the qpair.
 * \param cid Command ID of the command to abort.
 * \param cb_fn Callback function to invoke when the abort has completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated for this request, -ENXIO if the admin qpair is failed at the transport layer.
 */
int spdk_nvme_ctrlr_cmd_abort(struct spdk_nvme_ctrlr *ctrlr,
			      struct spdk_nvme_qpair *qpair,
			      uint16_t cid,
			      spdk_nvme_cmd_cb cb_fn,
			      void *cb_arg);

/**
 * Set specific feature for the given NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \sa spdk_nvme_ctrlr_cmd_get_feature().
 *
 * \param ctrlr NVMe controller to manipulate.
 * \param feature The feature identifier.
 * \param cdw11 as defined by the specification for this command.
 * \param cdw12 as defined by the specification for this command.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param cb_fn Callback function to invoke when the feature has been set.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated for this request, -ENXIO if the admin qpair is failed at the transport layer.
 */
int spdk_nvme_ctrlr_cmd_set_feature(struct spdk_nvme_ctrlr *ctrlr,
				    uint8_t feature, uint32_t cdw11, uint32_t cdw12,
				    void *payload, uint32_t payload_size,
				    spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Get specific feature from given NVMe controller.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \sa spdk_nvme_ctrlr_cmd_set_feature()
 *
 * \param ctrlr NVMe controller to query.
 * \param feature The feature identifier.
 * \param cdw11 as defined by the specification for this command.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param cb_fn Callback function to invoke when the feature has been retrieved.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, -ENOMEM if resources could not be allocated
 * for this request, -ENXIO if the admin qpair is failed at the transport layer.
 */
int spdk_nvme_ctrlr_cmd_get_feature(struct spdk_nvme_ctrlr *ctrlr,
				    uint8_t feature, uint32_t cdw11,
				    void *payload, uint32_t payload_size,
				    spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Get specific feature from given NVMe controller.
 *
 * \param ctrlr NVMe controller to query.
 * \param feature The feature identifier.
 * \param cdw11 as defined by the specification for this command.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param cb_fn Callback function to invoke when the feature has been retrieved.
 * \param cb_arg Argument to pass to the callback function.
 * \param ns_id The namespace identifier.
 *
 * \return 0 if successfully submitted, -ENOMEM if resources could not be allocated
 * for this request, -ENXIO if the admin qpair is failed at the transport layer.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * Call \ref spdk_nvme_ctrlr_process_admin_completions() to poll for completion
 * of commands submitted through this function.
 *
 * \sa spdk_nvme_ctrlr_cmd_set_feature_ns()
 */
int spdk_nvme_ctrlr_cmd_get_feature_ns(struct spdk_nvme_ctrlr *ctrlr, uint8_t feature,
				       uint32_t cdw11, void *payload, uint32_t payload_size,
				       spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t ns_id);

/**
 * Set specific feature for the given NVMe controller and namespace ID.
 *
 * \param ctrlr NVMe controller to manipulate.
 * \param feature The feature identifier.
 * \param cdw11 as defined by the specification for this command.
 * \param cdw12 as defined by the specification for this command.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param cb_fn Callback function to invoke when the feature has been set.
 * \param cb_arg Argument to pass to the callback function.
 * \param ns_id The namespace identifier.
 *
 * \return 0 if successfully submitted, -ENOMEM if resources could not be allocated
 * for this request, -ENXIO if the admin qpair is failed at the transport layer.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * Call \ref spdk_nvme_ctrlr_process_admin_completions() to poll for completion
 * of commands submitted through this function.
 *
 * \sa spdk_nvme_ctrlr_cmd_get_feature_ns()
 */
int spdk_nvme_ctrlr_cmd_set_feature_ns(struct spdk_nvme_ctrlr *ctrlr, uint8_t feature,
				       uint32_t cdw11, uint32_t cdw12, void *payload,
				       uint32_t payload_size, spdk_nvme_cmd_cb cb_fn,
				       void *cb_arg, uint32_t ns_id);

/**
 * Receive security protocol data from controller.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * \param ctrlr NVMe controller to use for security receive command submission.
 * \param secp Security Protocol that is used.
 * \param spsp Security Protocol Specific field.
 * \param nssf NVMe Security Specific field. Indicate RPMB target when using Security
 * Protocol EAh.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param cb_fn Callback function to invoke when the command has been completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be allocated
 * for this request.
 */
int spdk_nvme_ctrlr_cmd_security_receive(struct spdk_nvme_ctrlr *ctrlr, uint8_t secp,
		uint16_t spsp, uint8_t nssf, void *payload,
		uint32_t payload_size,
		spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Send security protocol data to controller.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * \param ctrlr NVMe controller to use for security send command submission.
 * \param secp Security Protocol that is used.
 * \param spsp Security Protocol Specific field.
 * \param nssf NVMe Security Specific field. Indicate RPMB target when using Security
 * Protocol EAh.
 * \param payload The pointer to the payload buffer.
 * \param payload_size The size of payload buffer.
 * \param cb_fn Callback function to invoke when the command has been completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be allocated
 * for this request.
 */
int spdk_nvme_ctrlr_cmd_security_send(struct spdk_nvme_ctrlr *ctrlr, uint8_t secp,
				      uint16_t spsp, uint8_t nssf, void *payload,
				      uint32_t payload_size, spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Receive security protocol data from controller.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \param ctrlr NVMe controller to use for security receive command submission.
 * \param secp Security Protocol that is used.
 * \param spsp Security Protocol Specific field.
 * \param nssf NVMe Security Specific field. Indicate RPMB target when using Security
 * Protocol EAh.
 * \param payload The pointer to the payload buffer.
 * \param size The size of payload buffer.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be allocated
 * for this request.
 */
int spdk_nvme_ctrlr_security_receive(struct spdk_nvme_ctrlr *ctrlr, uint8_t secp,
				     uint16_t spsp, uint8_t nssf, void *payload, size_t size);

/**
 * Send security protocol data to controller.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \param ctrlr NVMe controller to use for security send command submission.
 * \param secp Security Protocol that is used.
 * \param spsp Security Protocol Specific field.
 * \param nssf NVMe Security Specific field. Indicate RPMB target when using Security
 * Protocol EAh.
 * \param payload The pointer to the payload buffer.
 * \param size The size of payload buffer.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be allocated
 * for this request.
 */
int spdk_nvme_ctrlr_security_send(struct spdk_nvme_ctrlr *ctrlr, uint8_t secp,
				  uint16_t spsp, uint8_t nssf, void *payload, size_t size);

/**
 * Get supported flags of the controller.
 *
 * \param ctrlr NVMe controller to get flags.
 *
 * \return supported flags of this controller.
 */
uint64_t spdk_nvme_ctrlr_get_flags(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Attach the specified namespace to controllers.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \param ctrlr NVMe controller to use for command submission.
 * \param nsid Namespace identifier for namespace to attach.
 * \param payload The pointer to the controller list.
 *
 * \return 0 if successfully submitted, ENOMEM if resources could not be allocated
 * for this request.
 */
int spdk_nvme_ctrlr_attach_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid,
			      struct spdk_nvme_ctrlr_list *payload);

/**
 * Detach the specified namespace from controllers.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \param ctrlr NVMe controller to use for command submission.
 * \param nsid Namespace ID to detach.
 * \param payload The pointer to the controller list.
 *
 * \return 0 if successfully submitted, ENOMEM if resources could not be allocated
 * for this request
 */
int spdk_nvme_ctrlr_detach_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid,
			      struct spdk_nvme_ctrlr_list *payload);

/**
 * Create a namespace.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * \param ctrlr NVMe controller to create namespace on.
 * \param payload The pointer to the NVMe namespace data.
 *
 * \return Namespace ID (>= 1) if successfully created, or 0 if the request failed.
 */
uint32_t spdk_nvme_ctrlr_create_ns(struct spdk_nvme_ctrlr *ctrlr,
				   struct spdk_nvme_ns_data *payload);

/**
 * Delete a namespace.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * Call spdk_nvme_ctrlr_process_admin_completions() to poll for completion of
 * commands submitted through this function.
 *
 * \param ctrlr NVMe controller to delete namespace from.
 * \param nsid The namespace identifier.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated
 * for this request
 */
int spdk_nvme_ctrlr_delete_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid);

/**
 * Format NVM.
 *
 * This function requests a low-level format of the media.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * \param ctrlr NVMe controller to format.
 * \param nsid The namespace identifier. May be SPDK_NVME_GLOBAL_NS_TAG to format
 * all namespaces.
 * \param format The format information for the command.
 *
 * \return 0 if successfully submitted, negated errno if resources could not be
 * allocated for this request
 */
int spdk_nvme_ctrlr_format(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid,
			   struct spdk_nvme_format *format);

/**
 * Download a new firmware image.
 *
 * This function is thread safe and can be called at any point after spdk_nvme_probe().
 *
 * \param ctrlr NVMe controller to perform firmware operation on.
 * \param payload The data buffer for the firmware image.
 * \param size The data size will be downloaded.
 * \param slot The slot that the firmware image will be committed to.
 * \param commit_action The action to perform when firmware is committed.
 * \param completion_status output parameter. Contains the completion status of
 * the firmware commit operation.
 *
 * \return 0 if successfully submitted, ENOMEM if resources could not be allocated
 * for this request, -1 if the size is not multiple of 4.
 */
int spdk_nvme_ctrlr_update_firmware(struct spdk_nvme_ctrlr *ctrlr, void *payload, uint32_t size,
				    int slot, enum spdk_nvme_fw_commit_action commit_action,
				    struct spdk_nvme_status *completion_status);

/**
 * Return virtual address of PCIe NVM I/O registers
 *
 * This function returns a pointer to the PCIe I/O registers for a controller
 * or NULL if unsupported for this transport.
 *
 * \param ctrlr Controller whose registers are to be accessed.
 *
 * \return Pointer to virtual address of register bank, or NULL.
 */
volatile struct spdk_nvme_registers *spdk_nvme_ctrlr_get_registers(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Reserve the controller memory buffer for data transfer use.
 *
 * This function reserves the full size of the controller memory buffer
 * for use in data transfers. If submission queues or completion queues are
 * already placed in the controller memory buffer, this call will fail.
 *
 * \param ctrlr Controller from which to allocate memory buffer
 *
 * \return The size of the controller memory buffer on success. Negated errno
 * on failure.
 */
int spdk_nvme_ctrlr_reserve_cmb(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Map a previously reserved controller memory buffer so that it's data is
 * visible from the CPU. This operation is not always possible.
 *
 * \param ctrlr Controller that contains the memory buffer
 * \param size Size of buffer that was mapped.
 *
 * \return Pointer to controller memory buffer, or NULL on failure.
 */
void *spdk_nvme_ctrlr_map_cmb(struct spdk_nvme_ctrlr *ctrlr, size_t *size);

/**
 * Free a controller memory I/O buffer.
 *
 * \param ctrlr Controller from which to unmap the memory buffer.
 */
void spdk_nvme_ctrlr_unmap_cmb(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Get the transport ID for a given NVMe controller.
 *
 * \param ctrlr Controller to get the transport ID.
 * \return Pointer to the controller's transport ID.
 */
const struct spdk_nvme_transport_id *spdk_nvme_ctrlr_get_transport_id(
	struct spdk_nvme_ctrlr *ctrlr);

/**
 * Opaque handle for a poll group. A poll group is a collection of spdk_nvme_qpair
 * objects that are polled for completions as a unit.
 *
 * Returned by spdk_nvme_poll_group_create().
 */
struct spdk_nvme_poll_group;


/**
 * This function alerts the user to disconnected qpairs when calling
 * spdk_nvme_poll_group_process_completions.
 */
typedef void (*spdk_nvme_disconnected_qpair_cb)(struct spdk_nvme_qpair *qpair,
		void *poll_group_ctx);

/**
 * Create a new poll group.
 *
 * \param ctx A user supplied context that can be retrieved later with spdk_nvme_poll_group_get_ctx
 *
 * \return Pointer to the new poll group, or NULL on error.
 */
struct spdk_nvme_poll_group *spdk_nvme_poll_group_create(void *ctx);

/**
 * Add an spdk_nvme_qpair to a poll group. qpairs may only be added to
 * a poll group if they are in the disconnected state; i.e. either they were
 * just allocated and not yet connected or they have been disconnected with a call
 * to spdk_nvme_ctrlr_disconnect_io_qpair.
 *
 * \param group The group to which the qpair will be added.
 * \param qpair The qpair to add to the poll group.
 *
 * return 0 on success, -EINVAL if the qpair is not in the disabled state, -ENODEV if the transport
 * doesn't exist, -ENOMEM on memory allocation failures, or -EPROTO on a protocol (transport) specific failure.
 */
int spdk_nvme_poll_group_add(struct spdk_nvme_poll_group *group, struct spdk_nvme_qpair *qpair);

/**
 * Remove an spdk_nvme_qpair from a poll group.
 *
 * \param group The group from which to remove the qpair.
 * \param qpair The qpair to remove from the poll group.
 *
 * return 0 on success, -ENOENT if the qpair is not found in the group, or -EPROTO on a protocol (transport) specific failure.
 */
int spdk_nvme_poll_group_remove(struct spdk_nvme_poll_group *group, struct spdk_nvme_qpair *qpair);

/**
 * Destroy an empty poll group.
 *
 * \param group The group to destroy.
 *
 * return 0 on success, -EBUSY if the poll group is not empty.
 */
int spdk_nvme_poll_group_destroy(struct spdk_nvme_poll_group *group);

/**
 * Poll for completions on all qpairs in this poll group.
 *
 * the disconnected_qpair_cb will be called for all disconnected qpairs in the poll group
 * including qpairs which fail within the context of this call.
 * The user is responsible for trying to reconnect or destroy those qpairs.
 *
 * \param group The group on which to poll for completions.
 * \param completions_per_qpair The maximum number of completions per qpair.
 * \param disconnected_qpair_cb A callback function of type spdk_nvme_disconnected_qpair_cb. Must be non-NULL.
 *
 * return The number of completions across all qpairs, -EINVAL if no disconnected_qpair_cb is passed, or
 * -EIO if the shared completion queue cannot be polled for the RDMA transport.
 */
int64_t spdk_nvme_poll_group_process_completions(struct spdk_nvme_poll_group *group,
		uint32_t completions_per_qpair, spdk_nvme_disconnected_qpair_cb disconnected_qpair_cb);

/**
 * Retrieve the user context for this specific poll group.
 *
 * \param group The poll group from which to retrieve the context.
 *
 * \return A pointer to the user provided poll group context.
 */
void *spdk_nvme_poll_group_get_ctx(struct spdk_nvme_poll_group *group);

/**
 * Get the identify namespace data as defined by the NVMe specification.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace.
 *
 * \return a pointer to the namespace data.
 */
const struct spdk_nvme_ns_data *spdk_nvme_ns_get_data(struct spdk_nvme_ns *ns);

/**
 * Get the namespace id (index number) from the given namespace handle.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace.
 *
 * \return namespace id.
 */
uint32_t spdk_nvme_ns_get_id(struct spdk_nvme_ns *ns);

/**
 * Get the controller with which this namespace is associated.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace.
 *
 * \return a pointer to the controller.
 */
struct spdk_nvme_ctrlr *spdk_nvme_ns_get_ctrlr(struct spdk_nvme_ns *ns);

/**
 * Determine whether a namespace is active.
 *
 * Inactive namespaces cannot be the target of I/O commands.
 *
 * \param ns Namespace to query.
 *
 * \return true if active, or false if inactive.
 */
bool spdk_nvme_ns_is_active(struct spdk_nvme_ns *ns);

/**
 * Get the maximum transfer size, in bytes, for an I/O sent to the given namespace.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return the maximum transfer size in bytes.
 */
uint32_t spdk_nvme_ns_get_max_io_xfer_size(struct spdk_nvme_ns *ns);

/**
 * Get the sector size, in bytes, of the given namespace.
 *
 * This function returns the size of the data sector only.  It does not
 * include metadata size.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * /return the sector size in bytes.
 */
uint32_t spdk_nvme_ns_get_sector_size(struct spdk_nvme_ns *ns);

/**
 * Get the extended sector size, in bytes, of the given namespace.
 *
 * This function returns the size of the data sector plus metadata.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * /return the extended sector size in bytes.
 */
uint32_t spdk_nvme_ns_get_extended_sector_size(struct spdk_nvme_ns *ns);

/**
 * Get the number of sectors for the given namespace.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return the number of sectors.
 */
uint64_t spdk_nvme_ns_get_num_sectors(struct spdk_nvme_ns *ns);

/**
 * Get the size, in bytes, of the given namespace.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return the size of the given namespace in bytes.
 */
uint64_t spdk_nvme_ns_get_size(struct spdk_nvme_ns *ns);

/**
 * Get the end-to-end data protection information type of the given namespace.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return the end-to-end data protection information type.
 */
enum spdk_nvme_pi_type spdk_nvme_ns_get_pi_type(struct spdk_nvme_ns *ns);

/**
 * Get the metadata size, in bytes, of the given namespace.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return the metadata size of the given namespace in bytes.
 */
uint32_t spdk_nvme_ns_get_md_size(struct spdk_nvme_ns *ns);

/**
 * Check whether if the namespace can support extended LBA when end-to-end data
 * protection enabled.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return true if the namespace can support extended LBA when end-to-end data
 * protection enabled, or false otherwise.
 */
bool spdk_nvme_ns_supports_extended_lba(struct spdk_nvme_ns *ns);

/**
 * Check whether if the namespace supports compare operation
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return true if the namespace supports compare operation, or false otherwise.
 */
bool spdk_nvme_ns_supports_compare(struct spdk_nvme_ns *ns);

/**
 * Determine the value returned when reading deallocated blocks.
 *
 * If deallocated blocks return 0, the deallocate command can be used as a more
 * efficient alternative to the write_zeroes command, especially for large requests.
 *
 * \param ns Namespace.
 *
 * \return the logical block read value.
 */
enum spdk_nvme_dealloc_logical_block_read_value spdk_nvme_ns_get_dealloc_logical_block_read_value(
	struct spdk_nvme_ns *ns);

/**
 * Get the optimal I/O boundary, in blocks, for the given namespace.
 *
 * Read and write commands should not cross the optimal I/O boundary for best
 * performance.
 *
 * \param ns Namespace to query.
 *
 * \return Optimal granularity of I/O commands, in blocks, or 0 if no optimal
 * granularity is reported.
 */
uint32_t spdk_nvme_ns_get_optimal_io_boundary(struct spdk_nvme_ns *ns);

/**
 * Get the UUID for the given namespace.
 *
 * \param ns Namespace to query.
 *
 * \return a pointer to namespace UUID, or NULL if ns does not have a UUID.
 */
const struct spdk_uuid *spdk_nvme_ns_get_uuid(const struct spdk_nvme_ns *ns);

/**
 * \brief Namespace command support flags.
 */
enum spdk_nvme_ns_flags {
	SPDK_NVME_NS_DEALLOCATE_SUPPORTED	= 0x1, /**< The deallocate command is supported */
	SPDK_NVME_NS_FLUSH_SUPPORTED		= 0x2, /**< The flush command is supported */
	SPDK_NVME_NS_RESERVATION_SUPPORTED	= 0x4, /**< The reservation command is supported */
	SPDK_NVME_NS_WRITE_ZEROES_SUPPORTED	= 0x8, /**< The write zeroes command is supported */
	SPDK_NVME_NS_DPS_PI_SUPPORTED		= 0x10, /**< The end-to-end data protection is supported */
	SPDK_NVME_NS_EXTENDED_LBA_SUPPORTED	= 0x20, /**< The extended lba format is supported,
							      metadata is transferred as a contiguous
							      part of the logical block that it is associated with */
	SPDK_NVME_NS_WRITE_UNCORRECTABLE_SUPPORTED	= 0x40, /**< The write uncorrectable command is supported */
	SPDK_NVME_NS_COMPARE_SUPPORTED		= 0x80, /**< The compare command is supported */
};

/**
 * Get the flags for the given namespace.
 *
 * See spdk_nvme_ns_flags for the possible flags returned.
 *
 * This function is thread safe and can be called at any point while the controller
 * is attached to the SPDK NVMe driver.
 *
 * \param ns Namespace to query.
 *
 * \return the flags for the given namespace.
 */
uint32_t spdk_nvme_ns_get_flags(struct spdk_nvme_ns *ns);

/**
 * Restart the SGL walk to the specified offset when the command has scattered payloads.
 *
 * \param cb_arg Argument passed to readv/writev.
 * \param offset Offset for SGL.
 */
typedef void (*spdk_nvme_req_reset_sgl_cb)(void *cb_arg, uint32_t offset);

/**
 * Fill out *address and *length with the current SGL entry and advance to the next
 * entry for the next time the callback is invoked.
 *
 * The described segment must be physically contiguous.
 *
 * \param cb_arg Argument passed to readv/writev.
 * \param address Virtual address of this segment, a value of UINT64_MAX
 * means the segment should be described via Bit Bucket SGL.
 * \param length Length of this physical segment.
 */
typedef int (*spdk_nvme_req_next_sge_cb)(void *cb_arg, void **address, uint32_t *length);

/**
 * Submit a write I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the write I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to the data payload.
 * \param lba Starting LBA to write the data.
 * \param lba_count Length (in sectors) for the write operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined by the SPDK_NVME_IO_FLAGS_* entries in
 * spdk/nvme_spec.h, for this I/O.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_write(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair, void *payload,
			   uint64_t lba, uint32_t lba_count, spdk_nvme_cmd_cb cb_fn,
			   void *cb_arg, uint32_t io_flags);

/**
 * Submit a write I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the write I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param lba Starting LBA to write the data.
 * \param lba_count Length (in sectors) for the write operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 * \param reset_sgl_fn Callback function to reset scattered payload.
 * \param next_sge_fn Callback function to iterate each scattered payload memory
 * segment.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_writev(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
			    uint64_t lba, uint32_t lba_count,
			    spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t io_flags,
			    spdk_nvme_req_reset_sgl_cb reset_sgl_fn,
			    spdk_nvme_req_next_sge_cb next_sge_fn);

/**
 * Submit a write I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the write I/O
 * \param qpair I/O queue pair to submit the request
 * \param lba starting LBA to write the data
 * \param lba_count length (in sectors) for the write operation
 * \param cb_fn callback function to invoke when the I/O is completed
 * \param cb_arg argument to pass to the callback function
 * \param io_flags set flags, defined in nvme_spec.h, for this I/O
 * \param reset_sgl_fn callback function to reset scattered payload
 * \param next_sge_fn callback function to iterate each scattered
 * payload memory segment
 * \param metadata virtual address pointer to the metadata payload, the length
 * of metadata is specified by spdk_nvme_ns_get_md_size()
 * \param apptag_mask application tag mask.
 * \param apptag application tag to use end-to-end protection information.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_writev_with_md(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				    uint64_t lba, uint32_t lba_count,
				    spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t io_flags,
				    spdk_nvme_req_reset_sgl_cb reset_sgl_fn,
				    spdk_nvme_req_next_sge_cb next_sge_fn, void *metadata,
				    uint16_t apptag_mask, uint16_t apptag);

/**
 * Submit a write I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the write I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to the data payload.
 * \param metadata Virtual address pointer to the metadata payload, the length
 * of metadata is specified by spdk_nvme_ns_get_md_size().
 * \param lba Starting LBA to write the data.
 * \param lba_count Length (in sectors) for the write operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined by the SPDK_NVME_IO_FLAGS_* entries in
 * spdk/nvme_spec.h, for this I/O.
 * \param apptag_mask Application tag mask.
 * \param apptag Application tag to use end-to-end protection information.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_write_with_md(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				   void *payload, void *metadata,
				   uint64_t lba, uint32_t lba_count, spdk_nvme_cmd_cb cb_fn,
				   void *cb_arg, uint32_t io_flags,
				   uint16_t apptag_mask, uint16_t apptag);

/**
 * Submit a write zeroes I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the write zeroes I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param lba Starting LBA for this command.
 * \param lba_count Length (in sectors) for the write zero operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined by the SPDK_NVME_IO_FLAGS_* entries in
 * spdk/nvme_spec.h, for this I/O.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_write_zeroes(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				  uint64_t lba, uint32_t lba_count,
				  spdk_nvme_cmd_cb cb_fn, void *cb_arg,
				  uint32_t io_flags);

/**
 * Submit a write uncorrectable I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the write uncorrectable I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param lba Starting LBA for this command.
 * \param lba_count Length (in sectors) for the write uncorrectable operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_write_uncorrectable(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
		uint64_t lba, uint32_t lba_count,
		spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * \brief Submits a read I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the read I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to the data payload.
 * \param lba Starting LBA to read the data.
 * \param lba_count Length (in sectors) for the read operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_read(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair, void *payload,
			  uint64_t lba, uint32_t lba_count, spdk_nvme_cmd_cb cb_fn,
			  void *cb_arg, uint32_t io_flags);

/**
 * Submit a read I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the read I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param lba Starting LBA to read the data.
 * \param lba_count Length (in sectors) for the read operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 * \param reset_sgl_fn Callback function to reset scattered payload.
 * \param next_sge_fn Callback function to iterate each scattered payload memory
 * segment.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_readv(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
			   uint64_t lba, uint32_t lba_count,
			   spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t io_flags,
			   spdk_nvme_req_reset_sgl_cb reset_sgl_fn,
			   spdk_nvme_req_next_sge_cb next_sge_fn);

/**
 * Submit a read I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any given time.
 *
 * \param ns NVMe namespace to submit the read I/O
 * \param qpair I/O queue pair to submit the request
 * \param lba starting LBA to read the data
 * \param lba_count length (in sectors) for the read operation
 * \param cb_fn callback function to invoke when the I/O is completed
 * \param cb_arg argument to pass to the callback function
 * \param io_flags set flags, defined in nvme_spec.h, for this I/O
 * \param reset_sgl_fn callback function to reset scattered payload
 * \param next_sge_fn callback function to iterate each scattered
 * payload memory segment
 * \param metadata virtual address pointer to the metadata payload, the length
 *	           of metadata is specified by spdk_nvme_ns_get_md_size()
 * \param apptag_mask application tag mask.
 * \param apptag application tag to use end-to-end protection information.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_readv_with_md(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				   uint64_t lba, uint32_t lba_count,
				   spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t io_flags,
				   spdk_nvme_req_reset_sgl_cb reset_sgl_fn,
				   spdk_nvme_req_next_sge_cb next_sge_fn, void *metadata,
				   uint16_t apptag_mask, uint16_t apptag);

/**
 * Submits a read I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the read I/O
 * \param qpair I/O queue pair to submit the request
 * \param payload virtual address pointer to the data payload
 * \param metadata virtual address pointer to the metadata payload, the length
 * of metadata is specified by spdk_nvme_ns_get_md_size().
 * \param lba starting LBA to read the data.
 * \param lba_count Length (in sectors) for the read operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 * \param apptag_mask Application tag mask.
 * \param apptag Application tag to use end-to-end protection information.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_read_with_md(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				  void *payload, void *metadata,
				  uint64_t lba, uint32_t lba_count, spdk_nvme_cmd_cb cb_fn,
				  void *cb_arg, uint32_t io_flags,
				  uint16_t apptag_mask, uint16_t apptag);

/**
 * Submit a data set management request to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * This is a convenience wrapper that will automatically allocate and construct
 * the correct data buffers. Therefore, ranges does not need to be allocated from
 * pinned memory and can be placed on the stack. If a higher performance, zero-copy
 * version of DSM is required, simply build and submit a raw command using
 * spdk_nvme_ctrlr_cmd_io_raw().
 *
 * \param ns NVMe namespace to submit the DSM request
 * \param type A bit field constructed from \ref spdk_nvme_dsm_attribute.
 * \param qpair I/O queue pair to submit the request
 * \param ranges An array of \ref spdk_nvme_dsm_range elements describing the LBAs
 * to operate on.
 * \param num_ranges The number of elements in the ranges array.
 * \param cb_fn Callback function to invoke when the I/O is completed
 * \param cb_arg Argument to pass to the callback function
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 */
int spdk_nvme_ns_cmd_dataset_management(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
					uint32_t type,
					const struct spdk_nvme_dsm_range *ranges,
					uint16_t num_ranges,
					spdk_nvme_cmd_cb cb_fn,
					void *cb_arg);

/**
 * Submit a flush request to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the flush request.
 * \param qpair I/O queue pair to submit the request.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 */
int spdk_nvme_ns_cmd_flush(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
			   spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Submit a reservation register to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the reservation register request.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to the reservation register data.
 * \param ignore_key '1' the current reservation key check is disabled.
 * \param action Specifies the registration action.
 * \param cptpl Change the Persist Through Power Loss state.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_reservation_register(struct spdk_nvme_ns *ns,
		struct spdk_nvme_qpair *qpair,
		struct spdk_nvme_reservation_register_data *payload,
		bool ignore_key,
		enum spdk_nvme_reservation_register_action action,
		enum spdk_nvme_reservation_register_cptpl cptpl,
		spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Submits a reservation release to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the reservation release request.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to current reservation key.
 * \param ignore_key '1' the current reservation key check is disabled.
 * \param action Specifies the reservation release action.
 * \param type Reservation type for the namespace.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_reservation_release(struct spdk_nvme_ns *ns,
		struct spdk_nvme_qpair *qpair,
		struct spdk_nvme_reservation_key_data *payload,
		bool ignore_key,
		enum spdk_nvme_reservation_release_action action,
		enum spdk_nvme_reservation_type type,
		spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Submits a reservation acquire to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the reservation acquire request.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to reservation acquire data.
 * \param ignore_key '1' the current reservation key check is disabled.
 * \param action Specifies the reservation acquire action.
 * \param type Reservation type for the namespace.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_reservation_acquire(struct spdk_nvme_ns *ns,
		struct spdk_nvme_qpair *qpair,
		struct spdk_nvme_reservation_acquire_data *payload,
		bool ignore_key,
		enum spdk_nvme_reservation_acquire_action action,
		enum spdk_nvme_reservation_type type,
		spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Submit a reservation report to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the reservation report request.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer for reservation status data.
 * \param len Length bytes for reservation status data structure.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_reservation_report(struct spdk_nvme_ns *ns,
					struct spdk_nvme_qpair *qpair,
					void *payload, uint32_t len,
					spdk_nvme_cmd_cb cb_fn, void *cb_arg);

/**
 * Submit a compare I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the compare I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to the data payload.
 * \param lba Starting LBA to compare the data.
 * \param lba_count Length (in sectors) for the compare operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_compare(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair, void *payload,
			     uint64_t lba, uint32_t lba_count, spdk_nvme_cmd_cb cb_fn,
			     void *cb_arg, uint32_t io_flags);

/**
 * Submit a compare I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the compare I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param lba Starting LBA to compare the data.
 * \param lba_count Length (in sectors) for the compare operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 * \param reset_sgl_fn Callback function to reset scattered payload.
 * \param next_sge_fn Callback function to iterate each scattered payload memory
 * segment.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_comparev(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
			      uint64_t lba, uint32_t lba_count,
			      spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t io_flags,
			      spdk_nvme_req_reset_sgl_cb reset_sgl_fn,
			      spdk_nvme_req_next_sge_cb next_sge_fn);

/**
 * Submit a compare I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the compare I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param lba Starting LBA to compare the data.
 * \param lba_count Length (in sectors) for the compare operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 * \param reset_sgl_fn Callback function to reset scattered payload.
 * \param next_sge_fn Callback function to iterate each scattered payload memory
 * segment.
 * \param metadata Virtual address pointer to the metadata payload, the length
 * of metadata is specified by spdk_nvme_ns_get_md_size()
 * \param apptag_mask Application tag mask.
 * \param apptag Application tag to use end-to-end protection information.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int
spdk_nvme_ns_cmd_comparev_with_md(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				  uint64_t lba, uint32_t lba_count,
				  spdk_nvme_cmd_cb cb_fn, void *cb_arg, uint32_t io_flags,
				  spdk_nvme_req_reset_sgl_cb reset_sgl_fn,
				  spdk_nvme_req_next_sge_cb next_sge_fn, void *metadata,
				  uint16_t apptag_mask, uint16_t apptag);

/**
 * Submit a compare I/O to the specified NVMe namespace.
 *
 * The command is submitted to a qpair allocated by spdk_nvme_ctrlr_alloc_io_qpair().
 * The user must ensure that only one thread submits I/O on a given qpair at any
 * given time.
 *
 * \param ns NVMe namespace to submit the compare I/O.
 * \param qpair I/O queue pair to submit the request.
 * \param payload Virtual address pointer to the data payload.
 * \param metadata Virtual address pointer to the metadata payload, the length
 * of metadata is specified by spdk_nvme_ns_get_md_size().
 * \param lba Starting LBA to compare the data.
 * \param lba_count Length (in sectors) for the compare operation.
 * \param cb_fn Callback function to invoke when the I/O is completed.
 * \param cb_arg Argument to pass to the callback function.
 * \param io_flags Set flags, defined in nvme_spec.h, for this I/O.
 * \param apptag_mask Application tag mask.
 * \param apptag Application tag to use end-to-end protection information.
 *
 * \return 0 if successfully submitted, negated errnos on the following error conditions:
 * -EINVAL: The request is malformed.
 * -ENOMEM: The request cannot be allocated.
 * -ENXIO: The qpair is failed at the transport level.
 * -EFAULT: Invalid address was specified as part of payload.  cb_fn is also called
 *          with error status including dnr=1 in this case.
 */
int spdk_nvme_ns_cmd_compare_with_md(struct spdk_nvme_ns *ns, struct spdk_nvme_qpair *qpair,
				     void *payload, void *metadata,
				     uint64_t lba, uint32_t lba_count, spdk_nvme_cmd_cb cb_fn,
				     void *cb_arg, uint32_t io_flags,
				     uint16_t apptag_mask, uint16_t apptag);

/**
 * \brief Inject an error for the next request with a given opcode.
 *
 * \param ctrlr NVMe controller.
 * \param qpair I/O queue pair to add the error command,
 *              NULL for Admin queue pair.
 * \param opc Opcode for Admin or I/O commands.
 * \param do_not_submit True if matching requests should not be submitted
 *                      to the controller, but instead completed manually
 *                      after timeout_in_us has expired.  False if matching
 *                      requests should be submitted to the controller and
 *                      have their completion status modified after the
 *                      controller completes the request.
 * \param timeout_in_us Wait specified microseconds when do_not_submit is true.
 * \param err_count Number of matching requests to inject errors.
 * \param sct Status code type.
 * \param sc Status code.
 *
 * \return 0 if successfully enabled, ENOMEM if an error command
 *	     structure cannot be allocated.
 *
 * The function can be called multiple times to inject errors for different
 * commands.  If the opcode matches an existing entry, the existing entry
 * will be updated with the values specified.
 */
int spdk_nvme_qpair_add_cmd_error_injection(struct spdk_nvme_ctrlr *ctrlr,
		struct spdk_nvme_qpair *qpair,
		uint8_t opc,
		bool do_not_submit,
		uint64_t timeout_in_us,
		uint32_t err_count,
		uint8_t sct, uint8_t sc);

/**
 * \brief Clear the specified NVMe command with error status.
 *
 * \param ctrlr NVMe controller.
 * \param qpair I/O queue pair to remove the error command,
 * \            NULL for Admin queue pair.
 * \param opc Opcode for Admin or I/O commands.
 *
 * The function will remove specified command in the error list.
 */
void spdk_nvme_qpair_remove_cmd_error_injection(struct spdk_nvme_ctrlr *ctrlr,
		struct spdk_nvme_qpair *qpair,
		uint8_t opc);

/**
 * \brief Given NVMe status, return ASCII string for that error.
 *
 * \param status Status from NVMe completion queue element.
 * \return Returns status as an ASCII string.
 */
const char *spdk_nvme_cpl_get_status_string(const struct spdk_nvme_status *status);

/**
 * \brief Prints (SPDK_NOTICELOG) the contents of an NVMe submission queue entry (command).
 *
 * \param qpair Pointer to the NVMe queue pair - used to determine admin versus I/O queue.
 * \param cmd Pointer to the submission queue command to be formatted.
 */
void spdk_nvme_qpair_print_command(struct spdk_nvme_qpair *qpair,
				   struct spdk_nvme_cmd *cmd);

/**
 * \brief Prints (SPDK_NOTICELOG) the contents of an NVMe completion queue entry.
 *
 * \param qpair Pointer to the NVMe queue pair - presently unused.
 * \param cpl Pointer to the completion queue element to be formatted.
 */
void spdk_nvme_qpair_print_completion(struct spdk_nvme_qpair *qpair,
				      struct spdk_nvme_cpl *cpl);

struct ibv_context;
struct ibv_pd;
struct ibv_mr;

/**
 * RDMA Transport Hooks
 */
struct spdk_nvme_rdma_hooks {
	/**
	 * \brief Get an InfiniBand Verbs protection domain.
	 *
	 * \param trid the transport id
	 * \param verbs Infiniband verbs context
	 *
	 * \return pd of the nvme ctrlr
	 */
	struct ibv_pd *(*get_ibv_pd)(const struct spdk_nvme_transport_id *trid,
				     struct ibv_context *verbs);

	/**
	 * \brief Get an InfiniBand Verbs memory region for a buffer.
	 *
	 * \param pd The protection domain returned from get_ibv_pd
	 * \param buf Memory buffer for which an rkey should be returned.
	 * \param size size of buf
	 *
	 * \return Infiniband remote key (rkey) for this buf
	 */
	uint64_t (*get_rkey)(struct ibv_pd *pd, void *buf, size_t size);

	/**
	 * \brief Put back keys got from get_rkey.
	 *
	 * \param key The Infiniband remote key (rkey) got from get_rkey
	 *
	 */
	void (*put_rkey)(uint64_t key);
};

/**
 * \brief Set the global hooks for the RDMA transport, if necessary.
 *
 * This call is optional and must be performed prior to probing for
 * any devices. By default, the RDMA transport will use the ibverbs
 * library to create protection domains and register memory. This
 * is a mechanism to subvert that and use an existing registration.
 *
 * This function may only be called one time per process.
 *
 * \param hooks for initializing global hooks
 */
void spdk_nvme_rdma_init_hooks(struct spdk_nvme_rdma_hooks *hooks);

/**
 * Get name of cuse device associated with NVMe controller.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param name	Buffer of be filled with cuse device name.
 * \param size	Size of name buffer.
 *
 * \return 0 on success. Negated errno on the following error conditions:
 * -ENODEV: No cuse device registered for the controller.
 * -ENSPC: Too small buffer size passed. Value of size pointer changed to the required length.
 */
int spdk_nvme_cuse_get_ctrlr_name(struct spdk_nvme_ctrlr *ctrlr, char *name, size_t *size);

/**
 * Get name of cuse device associated with NVMe namespace.
 *
 * \param ctrlr Opaque handle to NVMe controller.
 * \param nsid	Namespace id.
 * \param name	Buffer of be filled with cuse device name.
 * \param size	Size of name buffer.
 *
 * \return 0 on success. Negated errno on the following error conditions:
 * -ENODEV: No cuse device registered for the namespace.
 * -ENSPC: Too small buffer size passed. Value of size pointer changed to the required length.
 */
int spdk_nvme_cuse_get_ns_name(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid,
			       char *name, size_t *size);

/**
 * Create a character device at the path specified (Experimental)
 *
 * The character device can handle ioctls and is compatible with a standard
 * Linux kernel NVMe device. Tools such as nvme-cli can be used to configure
 * SPDK devices through this interface.
 *
 * The user is expected to be polling the admin qpair for this controller periodically
 * for the CUSE device to function.
 *
 * \param ctrlr Opaque handle to the NVMe controller.
 *
 * \return 0 on success. Negated errno on failure.
 */
int spdk_nvme_cuse_register(struct spdk_nvme_ctrlr *ctrlr);

/**
 * Remove a previously created character device (Experimental)
 *
 * \param ctrlr Opaque handle to the NVMe controller.
 *
 * \return 0 on success. Negated errno on failure.
 */
int spdk_nvme_cuse_unregister(struct spdk_nvme_ctrlr *ctrlr);

int spdk_nvme_map_prps(void *prv, struct spdk_nvme_cmd *cmd, struct iovec *iovs,
		       uint32_t len, size_t mps,
		       void *(*gpa_to_vva)(void *prv, uint64_t addr, uint64_t len));

/**
 * Opaque handle for a transport poll group. Used by the transport function table.
 */
struct spdk_nvme_transport_poll_group;

/**
 * Update and populate namespace CUSE devices (Experimental)
 *
 * \param ctrlr Opaque handle to the NVMe controller.
 *
 */
void spdk_nvme_cuse_update_namespaces(struct spdk_nvme_ctrlr *ctrlr);

struct nvme_request;

struct spdk_nvme_transport;

struct spdk_nvme_transport_ops {
	char name[SPDK_NVMF_TRSTRING_MAX_LEN + 1];

	enum spdk_nvme_transport_type type;

	struct spdk_nvme_ctrlr *(*ctrlr_construct)(const struct spdk_nvme_transport_id *trid,
			const struct spdk_nvme_ctrlr_opts *opts,
			void *devhandle);

	int (*ctrlr_scan)(struct spdk_nvme_probe_ctx *probe_ctx, bool direct_connect);

	int (*ctrlr_destruct)(struct spdk_nvme_ctrlr *ctrlr);

	int (*ctrlr_enable)(struct spdk_nvme_ctrlr *ctrlr);

	int (*ctrlr_set_reg_4)(struct spdk_nvme_ctrlr *ctrlr, uint32_t offset, uint32_t value);

	int (*ctrlr_set_reg_8)(struct spdk_nvme_ctrlr *ctrlr, uint32_t offset, uint64_t value);

	int (*ctrlr_get_reg_4)(struct spdk_nvme_ctrlr *ctrlr, uint32_t offset, uint32_t *value);

	int (*ctrlr_get_reg_8)(struct spdk_nvme_ctrlr *ctrlr, uint32_t offset, uint64_t *value);

	uint32_t (*ctrlr_get_max_xfer_size)(struct spdk_nvme_ctrlr *ctrlr);

	uint16_t (*ctrlr_get_max_sges)(struct spdk_nvme_ctrlr *ctrlr);

	int (*ctrlr_reserve_cmb)(struct spdk_nvme_ctrlr *ctrlr);

	void *(*ctrlr_map_cmb)(struct spdk_nvme_ctrlr *ctrlr, size_t *size);

	int (*ctrlr_unmap_cmb)(struct spdk_nvme_ctrlr *ctrlr);

	struct spdk_nvme_qpair *(*ctrlr_create_io_qpair)(struct spdk_nvme_ctrlr *ctrlr, uint16_t qid,
			const struct spdk_nvme_io_qpair_opts *opts);

	int (*ctrlr_delete_io_qpair)(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_qpair *qpair);

	int (*ctrlr_connect_qpair)(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_qpair *qpair);

	void (*ctrlr_disconnect_qpair)(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_qpair *qpair);

	void (*qpair_abort_reqs)(struct spdk_nvme_qpair *qpair, uint32_t dnr);

	int (*qpair_reset)(struct spdk_nvme_qpair *qpair);

	int (*qpair_submit_request)(struct spdk_nvme_qpair *qpair, struct nvme_request *req);

	int32_t (*qpair_process_completions)(struct spdk_nvme_qpair *qpair, uint32_t max_completions);

	int (*qpair_iterate_requests)(struct spdk_nvme_qpair *qpair,
				      int (*iter_fn)(struct nvme_request *req, void *arg),
				      void *arg);

	void (*admin_qpair_abort_aers)(struct spdk_nvme_qpair *qpair);

	struct spdk_nvme_transport_poll_group *(*poll_group_create)(void);

	int (*poll_group_add)(struct spdk_nvme_transport_poll_group *tgroup, struct spdk_nvme_qpair *qpair);

	int (*poll_group_remove)(struct spdk_nvme_transport_poll_group *tgroup,
				 struct spdk_nvme_qpair *qpair);

	int (*poll_group_connect_qpair)(struct spdk_nvme_qpair *qpair);

	int (*poll_group_disconnect_qpair)(struct spdk_nvme_qpair *qpair);

	int64_t (*poll_group_process_completions)(struct spdk_nvme_transport_poll_group *tgroup,
			uint32_t completions_per_qpair, spdk_nvme_disconnected_qpair_cb disconnected_qpair_cb);

	int (*poll_group_destroy)(struct spdk_nvme_transport_poll_group *tgroup);
};

/**
 * Register the operations for a given transport type.
 *
 * This function should be invoked by referencing the macro
 * SPDK_NVME_TRANSPORT_REGISTER macro in the transport's .c file.
 *
 * \param ops The operations associated with an NVMe-oF transport.
 */
void spdk_nvme_transport_register(const struct spdk_nvme_transport_ops *ops);

/*
 * Macro used to register new transports.
 */
#define SPDK_NVME_TRANSPORT_REGISTER(name, transport_ops) \
static void __attribute__((constructor)) _spdk_nvme_transport_register_##name(void) \
{ \
	spdk_nvme_transport_register(transport_ops); \
}\

#ifdef __cplusplus
}
#endif

#endif