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freebsd/sys/cam/cam_sim.c
Edward Tomasz Napierala fa6099fda0 Add SIM refcounting. This is slightly different from what DragonFly
does - in DragonFly, it's cam_sim_release() what actually frees the
SIM; cam_sim_free does nothing more than calling cam_sim_release().
Here, we drain in cam_sim_free, waiting for refcount to drop to zero.
We cannot do the same think DragonFly does, because after cam_sim_free
returns, client would destroy the sim->mtx, and CAM would trip over
an initialized mutex.

Reviewed by:	scottl
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2008-12-16 16:57:33 +00:00

145 lines
3.7 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>
#define CAM_PATH_ANY (u_int32_t)-1
MALLOC_DEFINE(M_CAMSIM, "CAM SIM", "CAM SIM buffers");
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;
if (mtx == NULL)
return (NULL);
sim = (struct cam_sim *)malloc(sizeof(struct cam_sim),
M_CAMSIM, 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);
}
SLIST_INIT(&sim->ccb_freeq);
TAILQ_INIT(&sim->sim_doneq);
return (sim);
}
void
cam_sim_free(struct cam_sim *sim, int free_devq)
{
int error;
sim->refcount--;
if (sim->refcount > 0) {
error = msleep(sim, sim->mtx, PRIBIO, "simfree", 0);
KASSERT(error == 0, ("invalid error value for msleep(9)"));
}
KASSERT(sim->refcount == 0, ("sim->refcount == 0"));
if (free_devq)
cam_simq_free(sim->devq);
free(sim, M_CAMSIM);
}
void
cam_sim_release(struct cam_sim *sim)
{
KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
sim->refcount--;
if (sim->refcount <= 1)
wakeup(sim);
}
void
cam_sim_hold(struct cam_sim *sim)
{
KASSERT(sim->refcount >= 1, ("sim->refcount >= 1"));
sim->refcount++;
}
void
cam_sim_set_path(struct cam_sim *sim, u_int32_t path_id)
{
sim->path_id = path_id;
}