2017-04-11 07:48:57

by Johannes Thumshirn

[permalink] [raw]
Subject: [PATCH RESEND] 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 iscsi_prep_fn()
back to the block layer.

Signed-off-by: Johannes Thumshirn <[email protected]>
Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
Reviewed-by: Christoph Hellwig <[email protected]>
---
drivers/scsi/scsi_lib.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Re-send as in the initial send I forgot to Cc linux-scsi@

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


2017-04-11 18:43:32

by Bart Van Assche

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

On Tue, 2017-04-11 at 09:46 +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 iscsi_prep_fn()
^^^^^^^^^^^^^^^
There is no?iscsi_prep_fn() in the kernel tree. Did you perhaps mean
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
> Reviewed-by: Christoph Hellwig <[email protected]>

Commit fd3fc0b4d730 has a "Cc: stable" tag. I assume that that means that
this patch also needs that tag?

Otherwise this patch looks fine to me.

Bart.

2017-04-12 06:54:18

by Johannes Thumshirn

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

On Tue, Apr 11, 2017 at 06:43:22PM +0000, Bart Van Assche wrote:
> On Tue, 2017-04-11 at 09:46 +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 iscsi_prep_fn()
> ^^^^^^^^^^^^^^^
> There is no?iscsi_prep_fn() in the kernel tree. Did you perhaps mean
> scsi_prep_fn()?

*doh* Yup, you're right.

>
> > back to the block layer.
> >
> > Signed-off-by: Johannes Thumshirn <[email protected]>
> > Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers
> > Reviewed-by: Christoph Hellwig <[email protected]>
>
> Commit fd3fc0b4d730 has a "Cc: stable" tag. I assume that that means that
> this patch also needs that tag?

Probably yes. I'll include both "fixes" in my resend.

--
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