[SCSI] sas_ata: Satisfy libata qc function locking requirements

ata_qc_complete and ata_sas_queuecmd require that the port lock be held
when they are called.  sas_ata doesn't do this, leading to BUG messages
about qc tags newly allocated qc tags already being in use.  This patch
fixes the locking, which should clean up the rest of those messages.

So far I've tested this against an IBM x206m with two SATA disks with no
BUG messages and no other signs of things going wrong, and the machine
finally passed the pounder stress test.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index de42b5b801cd..0bb1a149a9c2 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -92,7 +92,9 @@ static void sas_ata_task_done(struct sas_task *task)
         struct task_status_struct *stat = &task->task_status;
         struct ata_task_resp *resp = (struct ata_task_resp *)stat->buf;
         enum ata_completion_errors ac;
+        unsigned long flags;
 
+        spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
         if (stat->stat == SAS_PROTO_RESPONSE) {
                 ata_tf_from_fis(resp->ending_fis, &dev->sata_dev.tf);
                 qc->err_mask |= ac_err_mask(dev->sata_dev.tf.command);
@@ -113,6 +115,8 @@ static void sas_ata_task_done(struct sas_task *task)
         }
 
         ata_qc_complete(qc);
+        spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
+
         list_del_init(&task->list);
         sas_free_task(task);
 }