This is a note to let you know that I've just added the patch titled
SCSI: fix eh wakeup (scsi_schedule_eh vs scsi_restart_operations)
to the 3.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-fix-eh-wakeup-scsi_schedule_eh-vs-scsi_restart_operations.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 57fc2e335fd3c2f898ee73570dc81426c28dc7b4 Mon Sep 17 00:00:00 2001
From: Dan Williams <[email protected]>
Date: Thu, 21 Jun 2012 23:25:32 -0700
Subject: SCSI: fix eh wakeup (scsi_schedule_eh vs scsi_restart_operations)
From: Dan Williams <[email protected]>
commit 57fc2e335fd3c2f898ee73570dc81426c28dc7b4 upstream.
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.
Reported-by: Tom Jackson <[email protected]>
Tested-by: Tom Jackson <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/scsi/scsi_error.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1687,6 +1687,20 @@ static void scsi_restart_operations(stru
* 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);
}
/**
Patches currently in stable-queue which might be from [email protected]
are
queue-3.5/scsi-libsas-continue-revalidation.patch
queue-3.5/scsi-fix-eh-wakeup-scsi_schedule_eh-vs-scsi_restart_operations.patch
queue-3.5/scsi-fix-hot-unplug-vs-async-scan-race.patch
queue-3.5/scsi-libsas-fix-sas_discover_devices-return-code-handling.patch
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