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When deregistering a bus, attempt to flush out all outstanding

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operations before returning. Point the bus at a dummy cam_sim
structure so that any CCBs will complete immediately with a
CAM_DEV_NOT_THERE status, and ensure that any xpt_schedule() calls
on the bus's devices will immediately call the peripheral's
periph_start() routine. Also repeat the async messages because
devices that were part of the way through being probed may appear
after the original AC_LOST_DEVICE was sent, and would otherwise
never go away.

These changes make it possible to deregister a bus and free the SIM
at most stages during bus probing without the usual crashes in
camisr(). In particular, plugging in a umass device and then
unplugging it as soon as the first probe messages appeared would
almost always result in a crash. Now the device just goes away with
a few CAM errors and all references to the CAM bus, target and
device are dropped correctly.
This commit is contained in:
Ian Dowse 2006-01-11 02:06:08 +00:00
parent 1c3a3b0bd0
commit d3ef345454
1 changed files with 111 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

119
sys/cam/cam_xpt.c
View File

@ -682,6 +682,18 @@ static struct cdevsw xpt_cdevsw = {
static struct intr_config_hook *xpt_config_hook;
static void dead_sim_action(struct cam_sim *sim, union ccb *ccb);
static void dead_sim_poll(struct cam_sim *sim);
/* Dummy SIM that is used when the real one has gone. */
static struct cam_sim cam_dead_sim = {
.sim_action = dead_sim_action,
.sim_poll = dead_sim_poll,
.sim_name = "dead_sim",
};
#define SIM_DEAD(sim) ((sim) == &cam_dead_sim)
/* Registered busses */
static TAILQ_HEAD(,cam_eb) xpt_busses;
static u_int bus_generation;
@ -3055,12 +3067,22 @@ xpt_action(union ccb *start_ccb)
case XPT_ENG_EXEC:
{
struct cam_path *path;
struct cam_sim *sim;
int s;
int runq;
path = start_ccb->ccb_h.path;
s = splsoftcam();
sim = path->bus->sim;
if (SIM_DEAD(sim)) {
/* The SIM has gone; just execute the CCB directly. */
cam_ccbq_send_ccb(&path->device->ccbq, start_ccb);
(*(sim->sim_action))(sim, start_ccb);
splx(s);
break;
}
cam_ccbq_insert_ccb(&path->device->ccbq, start_ccb);
if (path->device->qfrozen_cnt == 0)
runq = xpt_schedule_dev_sendq(path->bus, path->device);
@ -3641,8 +3663,8 @@ xpt_polled_action(union ccb *start_ccb)
dev->ccbq.devq_openings--;
dev->ccbq.dev_openings--;
while((devq->send_openings <= 0 || dev->ccbq.dev_openings < 0)
&& (--timeout > 0)) {
while(((devq != NULL && devq->send_openings <= 0) ||
dev->ccbq.dev_openings < 0) && (--timeout > 0)) {
DELAY(1000);
(*(sim->sim_poll))(sim);
camisr(&cam_bioq);
@ -3684,6 +3706,7 @@ void
xpt_schedule(struct cam_periph *perph, u_int32_t new_priority)
{
struct cam_ed *device;
union ccb *work_ccb;
int s;
int runq;
@ -3702,6 +3725,16 @@ xpt_schedule(struct cam_periph *perph, u_int32_t new_priority)
new_priority);
}
runq = 0;
} else if (SIM_DEAD(perph->path->bus->sim)) {
/* The SIM is gone so just call periph_start directly. */
work_ccb = xpt_get_ccb(perph->path->device);
splx(s);
if (work_ccb == NULL)
return; /* XXX */
xpt_setup_ccb(&work_ccb->ccb_h, perph->path, new_priority);
perph->pinfo.priority = new_priority;
perph->periph_start(perph, work_ccb);
return;
} else {
/* New entry on the queue */
CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
@ -4337,6 +4370,10 @@ xpt_release_ccb(union ccb *free_ccb)
} else {
SLIST_INSERT_HEAD(&ccb_freeq, &free_ccb->ccb_h, xpt_links.sle);
}
if (bus->sim->devq == NULL) {
splx(s);
return;
}
bus->sim->devq->alloc_openings++;
bus->sim->devq->alloc_active--;
/* XXX Turn this into an inline function - xpt_run_device?? */
@ -4422,6 +4459,12 @@ int32_t
xpt_bus_deregister(path_id_t pathid)
{
struct cam_path bus_path;
struct cam_ed *device;
struct cam_ed_qinfo *qinfo;
struct cam_devq *devq;
struct cam_periph *periph;
struct cam_sim *ccbsim;
union ccb *work_ccb;
cam_status status;
GIANT_REQUIRED;
@ -4433,11 +4476,51 @@ xpt_bus_deregister(path_id_t pathid)
xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);
/* The SIM may be gone, so use a dummy SIM for any stray operations. */
devq = bus_path.bus->sim->devq;
bus_path.bus->sim = &cam_dead_sim;
/* Execute any pending operations now. */
while ((qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
CAMQ_HEAD)) != NULL ||
(qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->alloc_queue,
CAMQ_HEAD)) != NULL) {
do {
device = qinfo->device;
work_ccb = cam_ccbq_peek_ccb(&device->ccbq, CAMQ_HEAD);
if (work_ccb != NULL) {
devq->active_dev = device;
cam_ccbq_remove_ccb(&device->ccbq, work_ccb);
cam_ccbq_send_ccb(&device->ccbq, work_ccb);
ccbsim = work_ccb->ccb_h.path->bus->sim;
(*(ccbsim->sim_action))(ccbsim, work_ccb);
}
periph = (struct cam_periph *)camq_remove(&device->drvq,
CAMQ_HEAD);
if (periph != NULL)
xpt_schedule(periph, periph->pinfo.priority);
} while (work_ccb != NULL || periph != NULL);
}
/* Make sure all completed CCBs are processed. */
while (!TAILQ_EMPTY(&cam_bioq)) {
camisr(&cam_bioq);
/* Repeat the async's for the benefit of any new devices. */
xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);
}
/* Release the reference count held while registered. */
xpt_release_bus(bus_path.bus);
xpt_release_path(&bus_path);
/* Recheck for more completed CCBs. */
while (!TAILQ_EMPTY(&cam_bioq))
camisr(&cam_bioq);
return (CAM_REQ_CMP);
}
@ -5021,6 +5104,9 @@ xpt_alloc_device(struct cam_eb *bus, struct cam_et *target, lun_id_t lun_id)
struct cam_devq *devq;
cam_status status;
if (SIM_DEAD(bus->sim))
return (NULL);
/* Make space for us in the device queue on our bus */
devq = bus->sim->devq;
status = cam_devq_resize(devq, devq->alloc_queue.array_size + 1);
@ -5131,9 +5217,11 @@ xpt_release_device(struct cam_eb *bus, struct cam_et *target,
TAILQ_REMOVE(&target->ed_entries, device,links);
target->generation++;
xpt_max_ccbs -= device->ccbq.devq_openings;
/* Release our slot in the devq */
devq = bus->sim->devq;
cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
if (!SIM_DEAD(bus->sim)) {
/* Release our slot in the devq */
devq = bus->sim->devq;
cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
}
splx(s);
camq_fini(&device->drvq);
camq_fini(&device->ccbq.queue);
@ -7096,8 +7184,10 @@ camisr(void *V_queue)
s = splcam();
cam_ccbq_ccb_done(&dev->ccbq, (union ccb *)ccb_h);
ccb_h->path->bus->sim->devq->send_active--;
ccb_h->path->bus->sim->devq->send_openings++;
if (!SIM_DEAD(ccb_h->path->bus->sim)) {
ccb_h->path->bus->sim->devq->send_active--;
ccb_h->path->bus->sim->devq->send_openings++;
}
splx(s);
if (((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0
@ -7145,3 +7235,16 @@ camisr(void *V_queue)
}
splx(s);
}
static void
dead_sim_action(struct cam_sim *sim, union ccb *ccb)
{
ccb->ccb_h.status = CAM_DEV_NOT_THERE;
xpt_done(ccb);
}
static void
dead_sim_poll(struct cam_sim *sim)
{
}