From: James Bottomley <James.Bottomley@suse.de>
To: Tejun Heo <tj@kernel.org>
Cc: Dan Carpenter <error27@gmail.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch] libsas: dereferencing variable before check
Date: Thu, 13 May 2010 09:31:54 -0500 [thread overview]
Message-ID: <1273761114.4353.122.camel@mulgrave.site> (raw)
In-Reply-To: <23e0bf65-8758-45b3-b0a8-1df97db07d9a@email.android.com>
On Thu, 2010-05-13 at 01:08 +0200, Tejun Heo wrote:
>
> "Dan Carpenter" <error27@gmail.com> wrote:
>
> >The "qc->scsicmd" could be null so I moved the dereference inside the
> >check. This was introduced by 70b25f890: "[SCSI] fix locking around
> >blk_abort_request()"
> >
> >Signed-off-by: Dan Carpenter <error27@gmail.com>
>
> Ooh.. right.
>
> Asked-by: Tejun Heo <tj@kernel.org>
Well, oops, yes. Two patches to fix one bug is a bit overboard, I
think, plus some code rearrangement to fix the locality of the problem
and ensure it doesn't happen again might be useful. What about this.
James
---
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 88f7446..8c496b5 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -395,12 +395,13 @@ 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) {
+ struct request_queue *q = qc->scsicmd->device->request_queue;
+ unsigned long flags;
+
spin_lock_irqsave(q->queue_lock, flags);
blk_abort_request(qc->scsicmd->request);
spin_unlock_irqrestore(q->queue_lock, flags);
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 8228350..53849f2 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -1030,8 +1030,6 @@ 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) {
@@ -1043,13 +1041,15 @@ void sas_task_abort(struct sas_task *task)
if (dev_is_sata(task->dev)) {
sas_ata_task_abort(task);
- return;
- }
+ } else {
+ struct request_queue *q = sc->device->request_queue;
+ unsigned long flags;
- 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);
+ 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);
+ }
}
int sas_slave_alloc(struct scsi_device *scsi_dev)
next prev parent reply other threads:[~2010-05-13 14:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-12 22:56 [patch] libsas: dereferencing variable before check Dan Carpenter
2010-05-12 23:08 ` Tejun Heo
2010-05-13 14:31 ` James Bottomley [this message]
2010-05-13 14:37 ` Tejun Heo
2010-05-13 18:42 ` Dan Carpenter
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