2017-04-12 07:23:33

by Johannes Thumshirn

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

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 <[email protected]>
Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
Cc: <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
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


2017-04-12 07:27:57

by Hannes Reinecke

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

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 <[email protected]>
> Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
> Cc: <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>
> ---
> 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 <[email protected]>

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
[email protected] +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N?rnberg
GF: F. Imend?rffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG N?rnberg)

2017-04-13 15:16:27

by Bart Van Assche

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

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 <[email protected]>

2017-04-14 02:13:20

by Martin K. Petersen

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

Johannes Thumshirn <[email protected]> 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