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 <jthumshirn@xxxxxxx> > Fixes: fd3fc0b4d730 scsi: don't BUG_ON() empty DMA transfers > Reviewed-by: Christoph Hellwig <hch@xxxxxx> 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.