[PATCH] sas_ata: satisfy libata qc function locking requirements

[PATCH] sas_ata: satisfy libata qc function locking requirements

[Darrick J. Wong]

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.  The patch is against jejb's
aic94xx-sas tree.

--

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

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index de42b5b..47fb274 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -92,6 +92,7 @@ static void sas_ata_task_done(struct sas
 	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;
 
 	if (stat->stat == SAS_PROTO_RESPONSE) {
 		ata_tf_from_fis(resp->ending_fis, &dev->sata_dev.tf);
@@ -112,7 +113,10 @@ static void sas_ata_task_done(struct sas
 		}
 	}
 
+	spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
 	ata_qc_complete(qc);
+	spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
+
 	list_del_init(&task->list);
 	sas_free_task(task);
 }
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 50cc22c..9d4d2ed 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -212,8 +212,12 @@ int sas_queuecommand(struct scsi_cmnd *c
 		struct sas_task *task;
 
 		if (dev_is_sata(dev)) {
+			unsigned long flags;
+
+			spin_lock_irqsave(dev->sata_dev.ap->lock, flags);
 			res = ata_sas_queuecmd(cmd, scsi_done,
 					       dev->sata_dev.ap);
+			spin_unlock_irqrestore(dev->sata_dev.ap->lock, flags);
 			goto out;
 		}
 

Re: [PATCH] sas_ata: satisfy libata qc function locking requirements

[Jeff Garzik]

Darrick J. Wong wrote:
> 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.  The patch is against jejb's
> aic94xx-sas tree.
> 
> --
> 
> Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>

heh, yeah, proper locking helps :)

Glad to hear the progress.  Adaptec just sent me a cable that will allow 
me to use my Razor card as a SATA controller, so I can finally start 
testing that.

	Jeff