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authorDan Williams <dan.j.williams@intel.com>2012-06-21 23:25:32 -0700
committerJames Bottomley <JBottomley@Parallels.com>2012-07-20 08:58:46 +0100
commit57fc2e335fd3c2f898ee73570dc81426c28dc7b4 (patch)
treef43508991715ad635c0b673185b2bf68de1ff674 /drivers/scsi
parente4a9c3732cea3e3c8c704aad86636090ffe6b25f (diff)
downloadlinux-57fc2e335fd3c2f898ee73570dc81426c28dc7b4.tar.bz2
[SCSI] fix eh wakeup (scsi_schedule_eh vs scsi_restart_operations)
Rapid ata hotplug on a libsas controller results in cases where libsas is waiting indefinitely on eh to perform an ata probe. A race exists between scsi_schedule_eh() and scsi_restart_operations() in the case when scsi_restart_operations() issues i/o to other devices in the sas domain. When this happens the host state transitions from SHOST_RECOVERY (set by scsi_schedule_eh) back to SHOST_RUNNING and ->host_busy is non-zero so we put the eh thread to sleep even though ->host_eh_scheduled is active. Before putting the error handler to sleep we need to check if the host_state needs to return to SHOST_RECOVERY for another trip through eh. Since i/o that is released by scsi_restart_operations has been blocked for at least one eh cycle, this implementation allows those i/o's to run before another eh cycle starts to discourage hung task timeouts. Cc: <stable@vger.kernel.org> Reported-by: Tom Jackson <thomas.p.jackson@intel.com> Tested-by: Tom Jackson <thomas.p.jackson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/scsi_error.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index d0f71e5d065f..804f63270e37 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1687,6 +1687,20 @@ static void scsi_restart_operations(struct Scsi_Host *shost)
* requests are started.
*/
scsi_run_host_queues(shost);
+
+ /*
+ * if eh is active and host_eh_scheduled is pending we need to re-run
+ * recovery. we do this check after scsi_run_host_queues() to allow
+ * everything pent up since the last eh run a chance to make forward
+ * progress before we sync again. Either we'll immediately re-run
+ * recovery or scsi_device_unbusy() will wake us again when these
+ * pending commands complete.
+ */
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (shost->host_eh_scheduled)
+ if (scsi_host_set_state(shost, SHOST_RECOVERY))
+ WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
+ spin_unlock_irqrestore(shost->host_lock, flags);
}
/**