This is a note to let you know that I've just added the patch titled
SCSI: qla2xxx: Test and clear FCPORT_UPDATE_NEEDED atomically.
to the 3.4-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-qla2xxx-test-and-clear-fcport_update_needed-atomically.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From a394aac88506159e047630fc90dc2242568382d8 Mon Sep 17 00:00:00 2001
From: David Jeffery <[email protected]>
Date: Wed, 21 Nov 2012 02:39:54 -0500
Subject: SCSI: qla2xxx: Test and clear FCPORT_UPDATE_NEEDED atomically.
From: David Jeffery <[email protected]>
commit a394aac88506159e047630fc90dc2242568382d8 upstream.
When the qla2xxx driver loses access to multiple, remote ports, there is a race
condition which can occur which will keep the request stuck on a scsi request
queue indefinitely.
This bad state occurred do to a race condition with how the FCPORT_UPDATE_NEEDED
bit is set in qla2x00_schedule_rport_del(), and how it is cleared in
qla2x00_do_dpc(). The problem port has its drport pointer set, but it has never
been processed by the driver to inform the fc transport that the port has been
lost. qla2x00_schedule_rport_del() sets drport, and then sets the
FCPORT_UPDATE_NEEDED bit. In qla2x00_do_dpc(), the port lists are walked and
any drport pointer is handled and the fc transport informed of the port loss,
then the FCPORT_UPDATE_NEEDED bit is cleared. This leaves a race where the
dpc thread is processing one port removal, another port removal is marked
with a call to qla2x00_schedule_rport_del(), and the dpc thread clears the
bit for both removals, even though only the first removal was actually
handled. Until another event occurs to set FCPORT_UPDATE_NEEDED, the later
port removal is never finished and qla2xxx stays in a bad state which causes
requests to become stuck on request queues.
This patch updates the driver to test and clear FCPORT_UPDATE_NEEDED
atomically. This ensures the port state changes are processed and not lost.
Signed-off-by: David Jeffery <[email protected]>
Signed-off-by: Chad Dupuis <[email protected]>
Signed-off-by: Saurav Kashyap <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/scsi/qla2xxx/qla_os.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -3735,9 +3735,9 @@ qla2x00_do_dpc(void *data)
"ISP abort end.\n");
}
- if (test_bit(FCPORT_UPDATE_NEEDED, &base_vha->dpc_flags)) {
+ if (test_and_clear_bit(FCPORT_UPDATE_NEEDED,
+ &base_vha->dpc_flags)) {
qla2x00_update_fcports(base_vha);
- clear_bit(FCPORT_UPDATE_NEEDED, &base_vha->dpc_flags);
}
if (test_bit(ISP_QUIESCE_NEEDED, &base_vha->dpc_flags)) {
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/scsi-qla2xxx-test-and-clear-fcport_update_needed-atomically.patch
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