freebsd-skq/sys/cam/cam_sim.c
Alexander Motin 401ed17ad0 Make CAM SIM lock optional.
For three years now CAM does not use SIM lock, but still enforces SIM to
use it.  Remove this requirement, allowing SIMs to have any locking they
prefer, if they pass no mutex to cam_sim_alloc().

MFC after:	2 weeks
2017-03-21 09:12:41 +00:00

174 lines
4.3 KiB
C

/*-
* Common functions for SCSI Interface Modules (SIMs).
*
* Copyright (c) 1997 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_sim.h>
#include <cam/cam_queue.h>
#include <cam/cam_xpt.h>
#define CAM_PATH_ANY (u_int32_t)-1
static MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
static struct mtx cam_sim_free_mtx;
MTX_SYSINIT(cam_sim_free_init, &cam_sim_free_mtx, "CAM SIM free lock", MTX_DEF);
struct cam_devq *
cam_simq_alloc(u_int32_t max_sim_transactions)
{
return (cam_devq_alloc(/*size*/0, max_sim_transactions));
}
void
cam_simq_free(struct cam_devq *devq)
{
cam_devq_free(devq);
}
struct cam_sim *
cam_sim_alloc(sim_action_func sim_action, sim_poll_func sim_poll,
const char *sim_name, void *softc, u_int32_t unit,
struct mtx *mtx, int max_dev_transactions,
int max_tagged_dev_transactions, struct cam_devq *queue)
{
struct cam_sim *sim;
sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
M_CAMSIM, M_ZERO | M_NOWAIT);
if (sim == NULL)
return (NULL);
sim->sim_action = sim_action;
sim->sim_poll = sim_poll;
sim->sim_name = sim_name;
sim->softc = softc;
sim->path_id = CAM_PATH_ANY;
sim->unit_number = unit;
sim->bus_id = 0; /* set in xpt_bus_register */
sim->max_tagged_dev_openings = max_tagged_dev_transactions;
sim->max_dev_openings = max_dev_transactions;
sim->flags = 0;
sim->refcount = 1;
sim->devq = queue;
sim->mtx = mtx;
if (mtx == &Giant) {
sim->flags |= 0;
callout_init(&sim->callout, 0);
} else {
sim->flags |= CAM_SIM_MPSAFE;
callout_init(&sim->callout, 1);
}
return (sim);
}
void
cam_sim_free(struct cam_sim *sim, int free_devq)
{
struct mtx *mtx = sim->mtx;
int error;
if (mtx) {
mtx_assert(mtx, MA_OWNED);
} else {
mtx = &cam_sim_free_mtx;
mtx_lock(mtx);
}
sim->refcount--;
if (sim->refcount > 0) {
error = msleep(sim, mtx, PRIBIO, "simfree", 0);
KASSERT(error == 0, ("invalid error value for msleep(9)"));
}
KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
if (sim->mtx == NULL)
mtx_unlock(mtx);
if (free_devq)
cam_simq_free(sim->devq);
free(sim, M_CAMSIM);
}
void
cam_sim_release(struct cam_sim *sim)
{
struct mtx *mtx = sim->mtx;
if (mtx) {
if (!mtx_owned(mtx))
mtx_lock(mtx);
else
mtx = NULL;
} else {
mtx = &cam_sim_free_mtx;
mtx_lock(mtx);
}
KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
sim->refcount--;
if (sim->refcount == 0)
wakeup(sim);
if (mtx)
mtx_unlock(mtx);
}
void
cam_sim_hold(struct cam_sim *sim)
{
struct mtx *mtx = sim->mtx;
if (mtx) {
if (!mtx_owned(mtx))
mtx_lock(mtx);
else
mtx = NULL;
} else {
mtx = &cam_sim_free_mtx;
mtx_lock(mtx);
}
KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
sim->refcount++;
if (mtx)
mtx_unlock(mtx);
}
void
cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
{
sim->path_id = path_id;
}