On Fri, Sep 18 2009 at 11:18am -0400, Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> wrote: > This is a preparation for the next patch, which changes > blk_set_default_limits() to set 0 for max_sectors/max_hw_sectors. > With the next patch, for dm targets like 'zero', where there's no > underlying device, those values remain 0 and the dm device becomes > unusable. > > So check the max_sectors and set to SAFE_MAX_SECTORS if 0. > > Check this thread for further background: > https://www.redhat.com/archives/dm-devel/2009-September/msg00176.html > > > Signed-off-by: Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx> > Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> > Cc: David Strand <dpstrand@xxxxxxxxx> > Cc: Mike Snitzer <snitzer@xxxxxxxxxx> > Cc: Alasdair G Kergon <agk@xxxxxxxxxx> > Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx> > Cc: Jens Axboe <jens.axboe@xxxxxxxxxx> > --- > drivers/md/dm-table.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > Index: linux-2.6.31.work/drivers/md/dm-table.c > =================================================================== > --- linux-2.6.31.work.orig/drivers/md/dm-table.c > +++ linux-2.6.31.work/drivers/md/dm-table.c > @@ -707,6 +707,17 @@ static int validate_hardware_logical_blo > device_logical_block_size_sects - next_target_start : 0; > } > > + /* > + * blk_set_default_limits() sets max_sectors/max_hw_sectors to 0. > + * When all targets have no underlying device, they are > + * left unchanged from the default values and cause problems. > + * Use SAFE_MAX_SECTORS for such cases. > + */ > + if (limits->max_hw_sectors == 0) > + limits->max_hw_sectors = SAFE_MAX_SECTORS; > + if (limits->max_sectors == 0) > + limits->max_sectors = SAFE_MAX_SECTORS; > + > if (remaining) { > DMWARN("%s: table line %u (start sect %llu len %llu) " > "not aligned to h/w logical block size %u", The blk_set_default_limits() that matters, as referenced in your comment block, is actually in dm_calculate_queue_limits(). It would be better to put these checks in dm_calculate_queue_limits() just before the call to validate_hardware_logical_block_alignment(). Either way works because the checks are effectively at the end of dm_calculate_queue_limits() -- which is where they need to be. But I think you're polluting validate_hardware_logical_block_alignment() with unrelated checks. Thanks, Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
