freebsd-skq/sys/cam/ctl/ctl_frontend.h
Alexander Motin 812c9f48a2 Save context switch per I/O for iSCSI and IOCTL frontends.
Introduce new CTL core KPI ctl_run(), preprocessing I/Os in the caller
context instead of scheduling another thread just for that.  This call
may sleep, that is not acceptable for some frontends like the original
CAM/FC one, but iSCSI already has separate sleepable per-connection RX
threads, and another thread scheduling is mostly just a waste of time.
IOCTL frontend actually waits for the I/O completion in the caller
thread, so the use of another thread for this has even less sense.

With this change I can measure ~5% IOPS improvement on 4KB iSCSI I/Os
to ZFS.

MFC after:	1 month
2021-02-18 22:29:38 -05:00

347 lines
13 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2003 Silicon Graphics International Corp.
* Copyright (c) 2014-2017 Alexander Motin <mav@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* $Id: //depot/users/kenm/FreeBSD-test2/sys/cam/ctl/ctl_frontend.h#2 $
* $FreeBSD$
*/
/*
* CAM Target Layer front end registration hooks
*
* Author: Ken Merry <ken@FreeBSD.org>
*/
#ifndef _CTL_FRONTEND_H_
#define _CTL_FRONTEND_H_
#include <cam/ctl/ctl_ioctl.h>
#include <sys/nv.h>
typedef enum {
CTL_PORT_STATUS_NONE = 0x00,
CTL_PORT_STATUS_ONLINE = 0x01,
CTL_PORT_STATUS_HA_SHARED = 0x02
} ctl_port_status;
typedef int (*fe_init_t)(void);
typedef int (*fe_shutdown_t)(void);
typedef void (*port_func_t)(void *onoff_arg);
typedef int (*port_info_func_t)(void *onoff_arg, struct sbuf *sb);
typedef int (*lun_func_t)(void *arg, int lun_id);
typedef int (*fe_ioctl_t)(struct cdev *dev, u_long cmd, caddr_t addr, int flag,
struct thread *td);
#define CTL_FRONTEND_DECLARE(name, driver) \
static int name ## _modevent(module_t mod, int type, void *data) \
{ \
switch (type) { \
case MOD_LOAD: \
return (ctl_frontend_register( \
(struct ctl_frontend *)data)); \
break; \
case MOD_UNLOAD: \
return (ctl_frontend_deregister( \
(struct ctl_frontend *)data)); \
break; \
default: \
return EOPNOTSUPP; \
} \
return 0; \
} \
static moduledata_t name ## _mod = { \
#name, \
name ## _modevent, \
(void *)&driver \
}; \
DECLARE_MODULE(name, name ## _mod, SI_SUB_CONFIGURE, SI_ORDER_FOURTH); \
MODULE_DEPEND(name, ctl, 1, 1, 1); \
MODULE_DEPEND(name, cam, 1, 1, 1)
struct ctl_wwpn_iid {
int in_use;
time_t last_use;
uint64_t wwpn;
char *name;
};
/*
* The ctl_frontend structure is the registration mechanism between a FETD
* (Front End Target Driver) and the CTL layer. Here is a description of
* the fields:
*
* port_type: This field tells CTL what kind of front end it is
* dealing with. This field serves two purposes.
* The first is to let CTL know whether the frontend
* in question is inside the main CTL module (i.e.
* the ioctl front end), and therefore its module
* reference count shouldn't be incremented. The
* CTL ioctl front end should continue to use the
* CTL_PORT_IOCTL argument as long as it is part of
* the main CTL module. The second is to let CTL
* know what kind of front end it is dealing with, so
* it can return the proper inquiry data for that
* particular port.
*
* num_requested_ctl_io: This is the number of ctl_io structures that the
* front end needs for its pool. This should
* generally be the maximum number of outstanding
* transactions that the FETD can handle. The CTL
* layer will add a few to this to account for
* ctl_io buffers queued for pending sense data.
* (Pending sense only gets queued if the FETD
* doesn't support autosense. e.g. non-packetized
* parallel SCSI doesn't support autosense.)
*
* port_name: A string describing the FETD. e.g. "LSI 1030T U320"
* or whatever you want to use to describe the driver.
*
* physical_port: This is the physical port number of this
* particular port within the driver/hardware. This
* number is hardware/driver specific.
* virtual_port: This is the virtual port number of this
* particular port. This is for things like NP-IV.
*
* port_online(): This function is called, with onoff_arg as its
* argument, by the CTL layer when it wants the FETD
* to start responding to selections on the specified
* target ID.
*
* port_offline(): This function is called, with onoff_arg as its
* argument, by the CTL layer when it wants the FETD
* to stop responding to selection on the specified
* target ID.
*
* onoff_arg: This is supplied as an argument to port_online()
* and port_offline(). This is specified by the
* FETD.
*
* lun_enable(): This function is called, with targ_lun_arg, a target
* ID and a LUN ID as its arguments, by CTL when it
* wants the FETD to enable a particular LUN. If the
* FETD doesn't really know about LUNs, it should
* just ignore this call and return 0. If the FETD
* cannot enable the requested LUN for some reason, the
* FETD should return non-zero status.
*
* lun_disable(): This function is called, with targ_lun_arg, a target
* ID and LUN ID as its arguments, by CTL when it
* wants the FETD to disable a particular LUN. If the
* FETD doesn't really know about LUNs, it should just
* ignore this call and return 0. If the FETD cannot
* disable the requested LUN for some reason, the
* FETD should return non-zero status.
*
* targ_lun_arg: This is supplied as an argument to the targ/lun
* enable/disable() functions. This is specified by
* the FETD.
*
* fe_datamove(): This function is called one or more times per I/O
* by the CTL layer to tell the FETD to initiate a
* DMA to or from the data buffer(s) specified by
* the passed-in ctl_io structure.
*
* fe_done(): This function is called by the CTL layer when a
* particular SCSI I/O or task management command has
* completed. For SCSI I/O requests (CTL_IO_SCSI),
* sense data is always supplied if the status is
* CTL_SCSI_ERROR and the SCSI status byte is
* SCSI_STATUS_CHECK_COND. If the FETD doesn't
* support autosense, the sense should be queued
* back to the CTL layer via ctl_queue_sense().
*
* fe_dump(): This function, if it exists, is called by CTL
* to request a dump of any debugging information or
* state to the console.
*
* targ_port: The CTL layer assigns a "port number" to every
* FETD. This port number should be passed back in
* in the header of every ctl_io that is queued to
* the CTL layer. This enables us to determine
* which bus the command came in on.
*
* ctl_pool_ref: Memory pool reference used by the FETD in calls to
* ctl_alloc_io().
*
* max_initiators: Maximum number of initiators that the FETD is
* allowed to have. Initiators should be numbered
* from 0 to max_initiators - 1. This value will
* typically be 16, and thus not a problem for
* parallel SCSI. This may present issues for Fibre
* Channel.
*
* wwnn World Wide Node Name to be used by the FETD.
* Note that this is set *after* registration. It
* will be set prior to the online function getting
* called.
*
* wwpn World Wide Port Name to be used by the FETD.
* Note that this is set *after* registration. It
* will be set prior to the online function getting
* called.
*
* status: Used by CTL to keep track of per-FETD state.
*
* links: Linked list pointers, used by CTL. The FETD
* shouldn't touch this field.
*/
struct ctl_port {
struct ctl_softc *ctl_softc;
struct ctl_frontend *frontend;
ctl_port_type port_type; /* passed to CTL */
int num_requested_ctl_io; /* passed to CTL */
char *port_name; /* passed to CTL */
int physical_port; /* passed to CTL */
int virtual_port; /* passed to CTL */
port_func_t port_online; /* passed to CTL */
port_func_t port_offline; /* passed to CTL */
port_info_func_t port_info; /* passed to CTL */
void *onoff_arg; /* passed to CTL */
lun_func_t lun_enable; /* passed to CTL */
lun_func_t lun_disable; /* passed to CTL */
int lun_map_size; /* passed to CTL */
uint32_t *lun_map; /* passed to CTL */
void *targ_lun_arg; /* passed to CTL */
void (*fe_datamove)(union ctl_io *io); /* passed to CTL */
void (*fe_done)(union ctl_io *io); /* passed to CTL */
int32_t targ_port; /* passed back to FETD */
void *ctl_pool_ref; /* passed back to FETD */
uint32_t max_initiators; /* passed back to FETD */
struct ctl_wwpn_iid *wwpn_iid; /* used by CTL */
uint64_t wwnn; /* set by CTL before online */
uint64_t wwpn; /* set by CTL before online */
ctl_port_status status; /* used by CTL */
nvlist_t *options; /* passed to CTL */
struct ctl_devid *port_devid; /* passed to CTL */
struct ctl_devid *target_devid; /* passed to CTL */
struct ctl_devid *init_devid; /* passed to CTL */
struct ctl_io_stats stats; /* used by CTL */
struct mtx port_lock; /* used by CTL */
STAILQ_ENTRY(ctl_port) fe_links; /* used by CTL */
STAILQ_ENTRY(ctl_port) links; /* used by CTL */
};
struct ctl_frontend {
char name[CTL_DRIVER_NAME_LEN]; /* passed to CTL */
fe_init_t init; /* passed to CTL */
fe_ioctl_t ioctl; /* passed to CTL */
void (*fe_dump)(void); /* passed to CTL */
fe_shutdown_t shutdown; /* passed to CTL */
STAILQ_HEAD(, ctl_port) port_list; /* used by CTL */
STAILQ_ENTRY(ctl_frontend) links; /* used by CTL */
};
/*
* This may block until resources are allocated. Called at FETD module load
* time. Returns 0 for success, non-zero for failure.
*/
int ctl_frontend_register(struct ctl_frontend *fe);
/*
* Called at FETD module unload time.
* Returns 0 for success, non-zero for failure.
*/
int ctl_frontend_deregister(struct ctl_frontend *fe);
/*
* Find the frontend by its name. Returns NULL if not found.
*/
struct ctl_frontend * ctl_frontend_find(char *frontend_name);
/*
* This may block until resources are allocated. Called at FETD module load
* time. Returns 0 for success, non-zero for failure.
*/
int ctl_port_register(struct ctl_port *port);
/*
* Called at FETD module unload time.
* Returns 0 for success, non-zero for failure.
*/
int ctl_port_deregister(struct ctl_port *port);
/*
* Called to set the WWNN and WWPN for a particular frontend.
*/
void ctl_port_set_wwns(struct ctl_port *port, int wwnn_valid,
uint64_t wwnn, int wwpn_valid, uint64_t wwpn);
/*
* Called to bring a particular frontend online.
*/
void ctl_port_online(struct ctl_port *fe);
/*
* Called to take a particular frontend offline.
*/
void ctl_port_offline(struct ctl_port *fe);
/*
* This routine queues I/O and task management requests from the FETD to the
* CTL layer. Returns immediately. Returns 0 for success, non-zero for
* failure.
*/
int ctl_queue(union ctl_io *io);
/*
* This routine starts execution of I/O and task management requests from
* the FETD to the CTL layer. May sleep. Returns 0 for success, non-zero
* for failure.
*/
int ctl_run(union ctl_io *io);
/*
* This routine is used if the front end interface doesn't support
* autosense (e.g. non-packetized parallel SCSI). This will queue the
* scsiio structure back to a per-lun pending sense queue. This MUST be
* called BEFORE any request sense can get queued to the CTL layer -- I
* need it in the queue in order to service the request. The scsiio
* structure passed in here will be freed by the CTL layer when sense is
* retrieved by the initiator. Returns 0 for success, non-zero for failure.
*/
int ctl_queue_sense(union ctl_io *io);
/*
* This routine adds an initiator to CTL's port database.
* The iid field should be the same as the iid passed in the nexus of each
* ctl_io from this initiator.
* The WWPN should be the FC WWPN, if available.
*/
int ctl_add_initiator(struct ctl_port *port, int iid, uint64_t wwpn, char *name);
/*
* This routine will remove an initiator from CTL's port database.
* The iid field should be the same as the iid passed in the nexus of each
* ctl_io from this initiator.
*/
int ctl_remove_initiator(struct ctl_port *port, int iid);
#endif /* _CTL_FRONTEND_H_ */