releases/2.6.33.4/scsi-fix-locking-around-blk_abort_request.patch

From 70b25f890ce9f0520c64075ce9225a5b020a513e Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Thu, 15 Apr 2010 09:00:08 +0900
Subject: SCSI: fix locking around blk_abort_request()

From: Tejun Heo <tj@kernel.org>

commit 70b25f890ce9f0520c64075ce9225a5b020a513e upstream.

blk_abort_request() expects queue lock to be held by the caller.
Grab it before calling the function.

Lack of this synchronization led to infinite loop on corrupt
q->timeout_list.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/scsi/libsas/sas_ata.c       |    4 ++++
 drivers/scsi/libsas/sas_scsi_host.c |    4 ++++
 2 files changed, 8 insertions(+)

--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -394,11 +394,15 @@ int sas_ata_init_host_and_port(struct do
 void sas_ata_task_abort(struct sas_task *task)
 {
 	struct ata_queued_cmd *qc = task->uldd_task;
+	struct request_queue *q = qc->scsicmd->device->request_queue;
 	struct completion *waiting;
+	unsigned long flags;
 
 	/* Bounce SCSI-initiated commands to the SCSI EH */
 	if (qc->scsicmd) {
+		spin_lock_irqsave(q->queue_lock, flags);
 		blk_abort_request(qc->scsicmd->request);
+		spin_unlock_irqrestore(q->queue_lock, flags);
 		scsi_schedule_eh(qc->scsicmd->device->host);
 		return;
 	}
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -1029,6 +1029,8 @@ int __sas_task_abort(struct sas_task *ta
 void sas_task_abort(struct sas_task *task)
 {
 	struct scsi_cmnd *sc = task->uldd_task;
+	struct request_queue *q = sc->device->request_queue;
+	unsigned long flags;
 
 	/* Escape for libsas internal commands */
 	if (!sc) {
@@ -1043,7 +1045,9 @@ void sas_task_abort(struct sas_task *tas
 		return;
 	}
 
+	spin_lock_irqsave(q->queue_lock, flags);
 	blk_abort_request(sc->request);
+	spin_unlock_irqrestore(q->queue_lock, flags);
 	scsi_schedule_eh(sc->device->host);
 }