Author: imp
Date: Tue May 15 22:22:10 2018
New Revision: 333651
URL: https://svnweb.freebsd.org/changeset/base/333651
Log:
Hold the reference count until the CCB is released
When a disk disappears and the periph is invalidated, any I/Os that
are pending with the controller can cause a crash when they
complete. Move to holding the softc reference count taken in dastart()
until the I/O is complete rather than only until xpt_action()
returns. (This approach was suggested by Ken Merry.) This extends
the method used in da to ada, nda, and mda.
Sponsored by: Netflix
Submitted by: Chuck Silvers
Modified:
head/sys/cam/ata/ata_da.c
head/sys/cam/mmc/mmc_da.c
head/sys/cam/nvme/nvme_da.c
Modified: head/sys/cam/ata/ata_da.c
==============================================================================
--- head/sys/cam/ata/ata_da.c Tue May 15 21:54:59 2018 (r333650)
+++ head/sys/cam/ata/ata_da.c Tue May 15 22:22:10 2018 (r333651)
@@ -2458,7 +2458,6 @@ out:
cam_periph_unlock(periph);
xpt_action(start_ccb);
cam_periph_lock(periph);
- softc->refcount--;
/* May have more work to do, so ensure we stay scheduled */
adaschedule(periph);
@@ -2856,10 +2855,13 @@ adadone(struct cam_periph *periph, union ccb *done_ccb
* We need to call cam_iosched before we call biodone so that we
* don't measure any activity that happens in the completion
* routine, which in the case of sendfile can be quite
- * extensive.
+ * extensive. Release the periph refcount taken in adastart()
+ * for each CCB.
*/
cam_iosched_bio_complete(softc->cam_iosched, bp, done_ccb);
xpt_release_ccb(done_ccb);
+ KASSERT(softc->refcount >= 1, ("adadone softc %p refcount %d",
softc, softc->refcount));
+ softc->refcount--;
if (state == ADA_CCB_TRIM) {
TAILQ_HEAD(, bio) queue;
struct bio *bp1;
Modified: head/sys/cam/mmc/mmc_da.c
==============================================================================
--- head/sys/cam/mmc/mmc_da.c Tue May 15 21:54:59 2018 (r333650)
+++ head/sys/cam/mmc/mmc_da.c Tue May 15 22:22:10 2018 (r333651)
@@ -1357,7 +1357,6 @@ sddastart(struct cam_periph *periph, union ccb *start_
cam_periph_unlock(periph);
xpt_action(start_ccb);
cam_periph_lock(periph);
- softc->refcount--;
/* May have more work to do, so ensure we stay scheduled */
sddaschedule(periph);
@@ -1418,6 +1417,11 @@ sddadone(struct cam_periph *periph, union ccb *done_cc
softc->outstanding_cmds--;
xpt_release_ccb(done_ccb);
+ /*
+ * Release the periph refcount taken in mdastart() for each CCB.
+ */
+ KASSERT(softc->refcount >= 1, ("mdadone softc %p refcount %d", softc,
softc->refcount));
+ softc->refcount--;
biodone(bp);
}
Modified: head/sys/cam/nvme/nvme_da.c
==============================================================================
--- head/sys/cam/nvme/nvme_da.c Tue May 15 21:54:59 2018 (r333650)
+++ head/sys/cam/nvme/nvme_da.c Tue May 15 22:22:10 2018 (r333651)
@@ -990,7 +990,6 @@ out:
cam_periph_unlock(periph);
xpt_action(start_ccb);
cam_periph_lock(periph);
- softc->refcount--;
/* May have more work to do, so ensure we stay scheduled */
ndaschedule(periph);
@@ -1101,6 +1100,11 @@ ndadone(struct cam_periph *periph, union ccb *done_ccb
biodone(bp2);
}
}
+ /*
+ * Release the periph refcount taken in mdastart() for each CCB.
+ */
+ KASSERT(softc->refcount >= 1, ("ndadone softc %p refcount %d",
softc, softc->refcount));
+ softc->refcount--;
return;
}
case NDA_CCB_DUMP:
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