From a414b72407d6729915dc1af4c21f1c40d328d7da Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Thu, 15 Apr 2010 09:00:08 +0900
Subject: [PATCH] SCSI: fix locking around blk_abort_request()

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(+)

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index e15501170698..816ab97eb16d 100644
--- 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 domain_device *found_dev,
 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;
 	}
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 1c558d3bce18..39fb9aa93fe5 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -1025,6 +1025,8 @@ int __sas_task_abort(struct sas_task *task)
 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) {
@@ -1039,7 +1041,9 @@ void sas_task_abort(struct sas_task *task)
 		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);
 }
 
-- 
2.34.1