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freebsd-skq/sys/cam/cam_periph.h
mav 99ff385fd0 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

253 lines
8.1 KiB
C
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/*-
* Data structures and definitions for CAM peripheral ("type") drivers.
*
* Copyright (c) 1997, 1998 Justin T. Gibbs.
* 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_PERIPH_H
#define _CAM_CAM_PERIPH_H 1
#include <sys/queue.h>
#include <cam/cam_sim.h>
#ifdef _KERNEL
#include <sys/taskqueue.h>
#include <cam/cam_xpt.h>
struct devstat;
extern struct cam_periph *xpt_periph;
extern struct periph_driver **periph_drivers;
void periphdriver_register(void *);
void periphdriver_init(int level);
#include <sys/module.h>
#define PERIPHDRIVER_DECLARE(name, driver) \
static int name ## _modevent(module_t mod, int type, void *data) \
{ \
switch (type) { \
case MOD_LOAD: \
periphdriver_register(data); \
break; \
case MOD_UNLOAD: \
printf(#name " module unload - not possible for this module type\n"); \
return EINVAL; \
default: \
return EOPNOTSUPP; \
} \
return 0; \
} \
static moduledata_t name ## _mod = { \
#name, \
name ## _modevent, \
(void *)&driver \
}; \
DECLARE_MODULE(name, name ## _mod, SI_SUB_DRIVERS, SI_ORDER_ANY); \
MODULE_DEPEND(name, cam, 1, 1, 1)
typedef void (periph_init_t)(void); /*
* Callback informing the peripheral driver
* it can perform it's initialization since
* the XPT is now fully initialized.
*/
typedef periph_init_t *periph_init_func_t;
struct periph_driver {
periph_init_func_t init;
char *driver_name;
TAILQ_HEAD(,cam_periph) units;
u_int generation;
u_int flags;
#define CAM_PERIPH_DRV_EARLY 0x01
};
typedef enum {
CAM_PERIPH_BIO
} cam_periph_type;
/* Generically useful offsets into the peripheral private area */
#define ppriv_ptr0 periph_priv.entries[0].ptr
#define ppriv_ptr1 periph_priv.entries[1].ptr
#define ppriv_field0 periph_priv.entries[0].field
#define ppriv_field1 periph_priv.entries[1].field
typedef void periph_start_t (struct cam_periph *periph,
union ccb *start_ccb);
typedef cam_status periph_ctor_t (struct cam_periph *periph,
void *arg);
typedef void periph_oninv_t (struct cam_periph *periph);
typedef void periph_dtor_t (struct cam_periph *periph);
struct cam_periph {
periph_start_t *periph_start;
periph_oninv_t *periph_oninval;
periph_dtor_t *periph_dtor;
char *periph_name;
struct cam_path *path; /* Compiled path to device */
void *softc;
struct cam_sim *sim;
u_int32_t unit_number;
cam_periph_type type;
u_int32_t flags;
#define CAM_PERIPH_RUNNING 0x01
#define CAM_PERIPH_LOCKED 0x02
#define CAM_PERIPH_LOCK_WANTED 0x04
#define CAM_PERIPH_INVALID 0x08
#define CAM_PERIPH_NEW_DEV_FOUND 0x10
#define CAM_PERIPH_RECOVERY_INPROG 0x20
#define CAM_PERIPH_RUN_TASK 0x40
#define CAM_PERIPH_FREE 0x80
#define CAM_PERIPH_ANNOUNCED 0x100
uint32_t scheduled_priority;
uint32_t immediate_priority;
int periph_allocating;
int periph_allocated;
u_int32_t refcount;
SLIST_HEAD(, ccb_hdr) ccb_list; /* For "immediate" requests */
SLIST_ENTRY(cam_periph) periph_links;
TAILQ_ENTRY(cam_periph) unit_links;
ac_callback_t *deferred_callback;
ac_code deferred_ac;
struct task periph_run_task;
};
#define CAM_PERIPH_MAXMAPS 2
struct cam_periph_map_info {
int num_bufs_used;
struct buf *bp[CAM_PERIPH_MAXMAPS];
};
cam_status cam_periph_alloc(periph_ctor_t *periph_ctor,
periph_oninv_t *periph_oninvalidate,
periph_dtor_t *periph_dtor,
periph_start_t *periph_start,
char *name, cam_periph_type type, struct cam_path *,
ac_callback_t *, ac_code, void *arg);
struct cam_periph *cam_periph_find(struct cam_path *path, char *name);
int cam_periph_list(struct cam_path *, struct sbuf *);
cam_status cam_periph_acquire(struct cam_periph *periph);
void cam_periph_release(struct cam_periph *periph);
void cam_periph_release_locked(struct cam_periph *periph);
void cam_periph_release_locked_buses(struct cam_periph *periph);
int cam_periph_hold(struct cam_periph *periph, int priority);
void cam_periph_unhold(struct cam_periph *periph);
void cam_periph_invalidate(struct cam_periph *periph);
int cam_periph_mapmem(union ccb *ccb,
struct cam_periph_map_info *mapinfo);
void cam_periph_unmapmem(union ccb *ccb,
struct cam_periph_map_info *mapinfo);
union ccb *cam_periph_getccb(struct cam_periph *periph,
u_int32_t priority);
void cam_periph_ccbwait(union ccb *ccb);
int cam_periph_runccb(union ccb *ccb,
int (*error_routine)(union ccb *ccb,
cam_flags camflags,
u_int32_t sense_flags),
cam_flags camflags, u_int32_t sense_flags,
struct devstat *ds);
int cam_periph_ioctl(struct cam_periph *periph, u_long cmd,
caddr_t addr,
int (*error_routine)(union ccb *ccb,
cam_flags camflags,
u_int32_t sense_flags));
void cam_freeze_devq(struct cam_path *path);
u_int32_t cam_release_devq(struct cam_path *path, u_int32_t relsim_flags,
u_int32_t opening_reduction, u_int32_t arg,
int getcount_only);
void cam_periph_async(struct cam_periph *periph, u_int32_t code,
struct cam_path *path, void *arg);
void cam_periph_bus_settle(struct cam_periph *periph,
u_int bus_settle_ms);
void cam_periph_freeze_after_event(struct cam_periph *periph,
struct timeval* event_time,
u_int duration_ms);
int cam_periph_error(union ccb *ccb, cam_flags camflags,
u_int32_t sense_flags, union ccb *save_ccb);
static __inline struct mtx *
cam_periph_mtx(struct cam_periph *periph)
{
return (xpt_path_mtx(periph->path));
}
#define cam_periph_owned(periph) \
mtx_owned(xpt_path_mtx((periph)->path))
#define cam_periph_lock(periph) \
mtx_lock(xpt_path_mtx((periph)->path))
#define cam_periph_unlock(periph) \
mtx_unlock(xpt_path_mtx((periph)->path))
#define cam_periph_assert(periph, what) \
mtx_assert(xpt_path_mtx((periph)->path), (what))
#define cam_periph_sleep(periph, chan, priority, wmesg, timo) \
xpt_path_sleep((periph)->path, (chan), (priority), (wmesg), (timo))
static inline struct cam_periph *
cam_periph_acquire_first(struct periph_driver *driver)
{
struct cam_periph *periph;
xpt_lock_buses();
periph = TAILQ_FIRST(&driver->units);
while (periph != NULL && (periph->flags & CAM_PERIPH_INVALID) != 0)
periph = TAILQ_NEXT(periph, unit_links);
if (periph != NULL)
periph->refcount++;
xpt_unlock_buses();
return (periph);
}
static inline struct cam_periph *
cam_periph_acquire_next(struct cam_periph *pperiph)
{
struct cam_periph *periph = pperiph;
cam_periph_assert(pperiph, MA_NOTOWNED);
xpt_lock_buses();
do {
periph = TAILQ_NEXT(periph, unit_links);
} while (periph != NULL && (periph->flags & CAM_PERIPH_INVALID) != 0);
if (periph != NULL)
periph->refcount++;
xpt_unlock_buses();
cam_periph_release(pperiph);
return (periph);
}
#define CAM_PERIPH_FOREACH(periph, driver) \
for ((periph) = cam_periph_acquire_first(driver); \
(periph) != NULL; \
(periph) = cam_periph_acquire_next(periph))
#endif /* _KERNEL */
#endif /* _CAM_CAM_PERIPH_H */
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