freebsd-skq/sys/cam/cam_xpt_internal.h
Alexander Motin 227d67aa54 Merge CAM locking changes from the projects/camlock branch to radically
reduce lock congestion and improve SMP scalability of the SCSI/ATA stack,
preparing the ground for the coming next GEOM direct dispatch support.

Replace big per-SIM locks with bunch of smaller ones:
 - per-LUN locks to protect device and peripheral drivers state;
 - per-target locks to protect list of LUNs on target;
 - per-bus locks to protect reference counting;
 - per-send queue locks to protect queue of CCBs to be sent;
 - per-done queue locks to protect queue of completed CCBs;
 - remaining per-SIM locks now protect only HBA driver internals.

While holding LUN lock it is allowed (while not recommended for performance
reasons) to take SIM lock.  The opposite acquisition order is forbidden.
All the other locks are leaf locks, that can be taken anywhere, but should
not be cascaded.  Many functions, such as: xpt_action(), xpt_done(),
xpt_async(), xpt_create_path(), etc. are no longer require (but allow) SIM
lock to be held.

To keep compatibility and solve cases where SIM lock can't be dropped, all
xpt_async() calls in addition to xpt_done() calls are queued to completion
threads for async processing in clean environment without SIM lock held.

Instead of single CAM SWI thread, used for commands completion processing
before, use multiple (depending on number of CPUs) threads.  Load balanced
between them using "hash" of the device B:T:L address.

HBA drivers that can drop SIM lock during completion processing and have
sufficient number of completion threads to efficiently scale to multiple
CPUs can use new function xpt_done_direct() to avoid extra context switch.
Make ahci(4) driver to use this mechanism depending on hardware setup.

Sponsored by:	iXsystems, Inc.
MFC after:	2 months
2013-10-21 12:00:26 +00:00

181 lines
5.8 KiB
C

/*-
* Copyright 2009 Scott Long
* 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, immediately at the beginning of the file.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, 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 DAMAGE.
*
* $FreeBSD$
*/
#ifndef _CAM_CAM_XPT_INTERNAL_H
#define _CAM_CAM_XPT_INTERNAL_H 1
#include <sys/taskqueue.h>
/* Forward Declarations */
struct cam_eb;
struct cam_et;
struct cam_ed;
typedef struct cam_ed * (*xpt_alloc_device_func)(struct cam_eb *bus,
struct cam_et *target,
lun_id_t lun_id);
typedef void (*xpt_release_device_func)(struct cam_ed *device);
typedef void (*xpt_action_func)(union ccb *start_ccb);
typedef void (*xpt_dev_async_func)(u_int32_t async_code,
struct cam_eb *bus,
struct cam_et *target,
struct cam_ed *device,
void *async_arg);
typedef void (*xpt_announce_periph_func)(struct cam_periph *periph);
struct xpt_xport {
xpt_alloc_device_func alloc_device;
xpt_release_device_func reldev;
xpt_action_func action;
xpt_dev_async_func async;
xpt_announce_periph_func announce;
};
/*
* The CAM EDT (Existing Device Table) contains the device information for
* all devices for all busses in the system. The table contains a
* cam_ed structure for each device on the bus.
*/
struct cam_ed {
cam_pinfo devq_entry;
TAILQ_ENTRY(cam_ed) links;
struct cam_et *target;
struct cam_sim *sim;
lun_id_t lun_id;
struct cam_ccbq ccbq; /* Queue of pending ccbs */
struct async_list asyncs; /* Async callback info for this B/T/L */
struct periph_list periphs; /* All attached devices */
u_int generation; /* Generation number */
void *quirk; /* Oddities about this device */
u_int maxtags;
u_int mintags;
cam_proto protocol;
u_int protocol_version;
cam_xport transport;
u_int transport_version;
struct scsi_inquiry_data inq_data;
uint8_t *supported_vpds;
uint8_t supported_vpds_len;
uint32_t device_id_len;
uint8_t *device_id;
uint8_t physpath_len;
uint8_t *physpath; /* physical path string form */
uint32_t rcap_len;
uint8_t *rcap_buf;
struct ata_params ident_data;
u_int8_t inq_flags; /*
* Current settings for inquiry flags.
* This allows us to override settings
* like disconnection and tagged
* queuing for a device.
*/
u_int8_t queue_flags; /* Queue flags from the control page */
u_int8_t serial_num_len;
u_int8_t *serial_num;
u_int32_t flags;
#define CAM_DEV_UNCONFIGURED 0x01
#define CAM_DEV_REL_TIMEOUT_PENDING 0x02
#define CAM_DEV_REL_ON_COMPLETE 0x04
#define CAM_DEV_REL_ON_QUEUE_EMPTY 0x08
#define CAM_DEV_TAG_AFTER_COUNT 0x20
#define CAM_DEV_INQUIRY_DATA_VALID 0x40
#define CAM_DEV_IN_DV 0x80
#define CAM_DEV_DV_HIT_BOTTOM 0x100
#define CAM_DEV_IDENTIFY_DATA_VALID 0x200
u_int32_t tag_delay_count;
#define CAM_TAG_DELAY_COUNT 5
u_int32_t tag_saved_openings;
u_int32_t refcount;
struct callout callout;
STAILQ_ENTRY(cam_ed) highpowerq_entry;
struct mtx device_mtx;
struct task device_destroy_task;
};
/*
* Each target is represented by an ET (Existing Target). These
* entries are created when a target is successfully probed with an
* identify, and removed when a device fails to respond after a number
* of retries, or a bus rescan finds the device missing.
*/
struct cam_et {
TAILQ_HEAD(, cam_ed) ed_entries;
TAILQ_ENTRY(cam_et) links;
struct cam_eb *bus;
target_id_t target_id;
u_int32_t refcount;
u_int generation;
struct timeval last_reset;
u_int rpl_size;
struct scsi_report_luns_data *luns;
struct mtx luns_mtx; /* Protection for luns field. */
};
/*
* Each bus is represented by an EB (Existing Bus). These entries
* are created by calls to xpt_bus_register and deleted by calls to
* xpt_bus_deregister.
*/
struct cam_eb {
TAILQ_HEAD(, cam_et) et_entries;
TAILQ_ENTRY(cam_eb) links;
path_id_t path_id;
struct cam_sim *sim;
struct timeval last_reset;
u_int32_t flags;
#define CAM_EB_RUNQ_SCHEDULED 0x01
u_int32_t refcount;
u_int generation;
device_t parent_dev;
struct xpt_xport *xport;
struct mtx eb_mtx; /* Bus topology mutex. */
};
struct cam_path {
struct cam_periph *periph;
struct cam_eb *bus;
struct cam_et *target;
struct cam_ed *device;
};
struct xpt_xport * scsi_get_xport(void);
struct xpt_xport * ata_get_xport(void);
struct cam_ed * xpt_alloc_device(struct cam_eb *bus,
struct cam_et *target,
lun_id_t lun_id);
void xpt_acquire_device(struct cam_ed *device);
void xpt_release_device(struct cam_ed *device);
u_int32_t xpt_dev_ccbq_resize(struct cam_path *path, int newopenings);
void xpt_start_tags(struct cam_path *path);
void xpt_stop_tags(struct cam_path *path);
MALLOC_DECLARE(M_CAMXPT);
#endif