[PATCH v2] scsi: return correct blkprep status code in case scsi_init_io() fails.

[PATCH v2] scsi: return correct blkprep status code in case scsi_init_io() fails.

[Johannes Thumshirn]

When instrumenting the SCSI layer to run into the
!blk_rq_nr_phys_segments(rq) case the following  warning emitted from the
block layer:

blk_peek_request: bad return=-22

This happens because since commit fd3fc0b4d730 ('scsi: don't BUG_ON()
empty DMA transfers') we return the wrong error value from scsi_prep_fn()
back to the block layer.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
Cc: <stable@vger.kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
Changes to v1:
* s/iscsi_prep_fn()/scsi_prep_fn()
* Add Cc stable

 drivers/scsi/scsi_lib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 19125d72f322..5558e212368b 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1061,10 +1061,10 @@ int scsi_init_io(struct scsi_cmnd *cmd)
 	struct scsi_device *sdev = cmd->device;
 	struct request *rq = cmd->request;
 	bool is_mq = (rq->mq_ctx != NULL);
-	int error;
+	int error = BLKPREP_KILL;
 
 	if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
-		return -EINVAL;
+		goto err_exit;
 
 	error = scsi_init_sgtable(rq, &cmd->sdb);
 	if (error)
-- 
2.12.0

Re: [PATCH v2] scsi: return correct blkprep status code in case scsi_init_io() fails.

[Hannes Reinecke]

On 04/12/2017 09:21 AM, Johannes Thumshirn wrote:
> When instrumenting the SCSI layer to run into the
> !blk_rq_nr_phys_segments(rq) case the following  warning emitted from the
> block layer:
> 
> blk_peek_request: bad return=-22
> 
> This happens because since commit fd3fc0b4d730 ('scsi: don't BUG_ON()
> empty DMA transfers') we return the wrong error value from scsi_prep_fn()
> back to the block layer.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
> Cc: <stable@vger.kernel.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
> Changes to v1:
> * s/iscsi_prep_fn()/scsi_prep_fn()
> * Add Cc stable
> 
>  drivers/scsi/scsi_lib.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 19125d72f322..5558e212368b 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1061,10 +1061,10 @@ int scsi_init_io(struct scsi_cmnd *cmd)
>  	struct scsi_device *sdev = cmd->device;
>  	struct request *rq = cmd->request;
>  	bool is_mq = (rq->mq_ctx != NULL);
> -	int error;
> +	int error = BLKPREP_KILL;
>  
>  	if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
> -		return -EINVAL;
> +		goto err_exit;
>  
>  	error = scsi_init_sgtable(rq, &cmd->sdb);
>  	if (error)
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

Re: [PATCH v2] scsi: return correct blkprep status code in case scsi_init_io() fails.

[Bart Van Assche]

On Wed, 2017-04-12 at 09:21 +0200, Johannes Thumshirn wrote:
> When instrumenting the SCSI layer to run into the
> !blk_rq_nr_phys_segments(rq) case the following  warning emitted from the
> block layer:
> 
> blk_peek_request: bad return=-22
> 
> This happens because since commit fd3fc0b4d730 ('scsi: don't BUG_ON()
> empty DMA transfers') we return the wrong error value from scsi_prep_fn()
> back to the block layer.

Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>

Re: [PATCH v2] scsi: return correct blkprep status code in case scsi_init_io() fails.

[Martin K. Petersen]

Johannes Thumshirn <jthumshirn@suse.de> writes:

> When instrumenting the SCSI layer to run into the
> !blk_rq_nr_phys_segments(rq) case the following warning emitted from
> the block layer:

Applied to 4.11/scsi-fixes.

-- 
Martin K. Petersen	Oracle Linux Engineering