[PATCH] scsi: Double completion on retry

[PATCH] scsi: Double completion on retry

[Hannes Reinecke]

When blk_end_request() returns 'false' in scsi_end_request the
request is invalid after blk_end_request_all(). So we must not
return the then stale request pointer. Doing so will result
in a potential double completion.
And we should be calling scsi_release_buffers() before
blk_end_request_all().

Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Hannes Reinecke <hare@suse.de>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c31187d..8dba66b 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -581,9 +581,11 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
 	 */
 	if (blk_end_request(req, error, bytes)) {
 		/* kill remainder if no retrys */
-		if (error && scsi_noretry_cmd(cmd))
+		if (error && scsi_noretry_cmd(cmd)) {
+			scsi_release_buffers(cmd);
 			blk_end_request_all(req, error);
-		else {
+			cmd = NULL;
+		} else {
 			if (requeue) {
 				/*
 				 * Bleah.  Leftovers again.  Stick the

Re: [PATCH] scsi: Double completion on retry

[Hannes Reinecke]

On 05/02/2013 10:31 AM, Hannes Reinecke wrote:
> When blk_end_request() returns 'false' in scsi_end_request the
> request is invalid after blk_end_request_all(). So we must not
> return the then stale request pointer. Doing so will result
> in a potential double completion.
> And we should be calling scsi_release_buffers() before
> blk_end_request_all().
> 
> Cc: Mike Christie <michaelc@cs.wisc.edu>
> Cc: Tejun Heo <tj@kernel.org>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index c31187d..8dba66b 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -581,9 +581,11 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
>  	 */
>  	if (blk_end_request(req, error, bytes)) {
>  		/* kill remainder if no retrys */
> -		if (error && scsi_noretry_cmd(cmd))
> +		if (error && scsi_noretry_cmd(cmd)) {
> +			scsi_release_buffers(cmd);
>  			blk_end_request_all(req, error);
> -		else {
> +			cmd = NULL;
> +		} else {
>  			if (requeue) {
>  				/*
>  				 * Bleah.  Leftovers again.  Stick the
> 
Bah, forget it. Patch is wrong.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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