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Rearrange how things are done to avoid dereferencing stale pointers in

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the case of immediate unconfigure after configure. Hold the periph an
extra count while we have the task to create sysctl context outstanding
so that the periph doesn't go away unexpectedly.

Sponsored by:	Panasas
Reviewed by:	scsi@
MFC after:	1 month
This commit is contained in:
Matt Jacob 2010-06-08 22:46:44 +00:00
parent 59ccfe8176
commit 63ebd216e7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=208928
1 changed files with 34 additions and 32 deletions
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66
sys/cam/scsi/scsi_da.c
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@ -998,11 +998,6 @@ dacleanup(struct cam_periph *periph)
xpt_print(periph->path, "can't remove sysctl context\n");
}
/*
* Nullify our periph pointer here to try and catch
* race conditions in callbacks/downcalls.
*/
softc->disk->d_drv1 = NULL;
disk_destroy(softc->disk);
callout_drain(&softc->sendordered_c);
free(softc, M_DEVBUF);
@ -1082,8 +1077,13 @@ dasysctlinit(void *context, int pending)
struct ccb_trans_settings cts;
periph = (struct cam_periph *)context;
if (cam_periph_acquire(periph) != CAM_REQ_CMP)
/*
* periph was held for us when this task was enqueued
*/
if (periph->flags & CAM_PERIPH_INVALID) {
cam_periph_release(periph);
return;
}
softc = (struct da_softc *)periph->softc;
snprintf(tmpstr, sizeof(tmpstr), "CAM DA unit %d", periph->unit_number);
@ -1263,6 +1263,33 @@ daregister(struct cam_periph *periph, void *arg)
* Register this media as a disk
*/
/*
* Add async callbacks for bus reset and
* bus device reset calls. I don't bother
* checking if this fails as, in most cases,
* the system will function just fine without
* them and the only alternative would be to
* not attach the device on failure.
*/
xpt_register_async(AC_SENT_BDR | AC_BUS_RESET | AC_LOST_DEVICE,
daasync, periph, periph->path);
/*
* Take an exclusive refcount on the periph while dastart is called
* to finish the probe. The reference will be dropped in dadone at
* the end of probe.
*/
(void)cam_periph_hold(periph, PRIBIO);
/*
* Schedule a periodic event to occasionally send an
* ordered tag to a device.
*/
callout_init_mtx(&softc->sendordered_c, periph->sim->mtx, 0);
callout_reset(&softc->sendordered_c,
(DA_DEFAULT_TIMEOUT * hz) / DA_ORDEREDTAG_INTERVAL,
dasendorderedtag, softc);
mtx_unlock(periph->sim->mtx);
softc->disk = disk_alloc();
softc->disk->d_open = daopen;
@ -1286,34 +1313,8 @@ daregister(struct cam_periph *periph, void *arg)
disk_create(softc->disk, DISK_VERSION);
mtx_lock(periph->sim->mtx);
/*
* Add async callbacks for bus reset and
* bus device reset calls. I don't bother
* checking if this fails as, in most cases,
* the system will function just fine without
* them and the only alternative would be to
* not attach the device on failure.
*/
xpt_register_async(AC_SENT_BDR | AC_BUS_RESET | AC_LOST_DEVICE,
daasync, periph, periph->path);
/*
* Take an exclusive refcount on the periph while dastart is called
* to finish the probe. The reference will be dropped in dadone at
* the end of probe.
*/
(void)cam_periph_hold(periph, PRIBIO);
xpt_schedule(periph, CAM_PRIORITY_DEV);
/*
* Schedule a periodic event to occasionally send an
* ordered tag to a device.
*/
callout_init_mtx(&softc->sendordered_c, periph->sim->mtx, 0);
callout_reset(&softc->sendordered_c,
(DA_DEFAULT_TIMEOUT * hz) / DA_ORDEREDTAG_INTERVAL,
dasendorderedtag, softc);
return(CAM_REQ_CMP);
}
@ -1773,6 +1774,7 @@ dadone(struct cam_periph *periph, union ccb *done_ccb)
* Create our sysctl variables, now that we know
* we have successfully attached.
*/
(void) cam_periph_acquire(periph); /* increase the refcount */
taskqueue_enqueue(taskqueue_thread,&softc->sysctl_task);
}
softc->state = DA_STATE_NORMAL;