On Tue, Jul 30, 2019 at 3:01 PM Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > On Tue, Jul 30 2019 at 5:38pm -0400, > Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > > > On Tue, Jul 30, 2019 at 12:07 PM Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > > > > I staged the fix (which I tweaked) here: > > > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.3&id=95b9ebb78c4c733f8912a195fbd0bc19960e726e > > > > Thanks for picking this up Mike, but I'd prefer to just teach > > dax_synchronous() to return false if the passed in dax_dev is NULL. > > Thoughts? > > I considered that too but I moved away from it because I'm so used to > the various block interfaces requiring the caller pass a non-NULL > pointer (e.g. request_queue): > > $ grep -ri return drivers/md/dm-table.c | grep \&\& > drivers/md/dm-table.c: return dev->dax_dev && dax_synchronous(dev->dax_dev); > drivers/md/dm-table.c: return q && blk_queue_zoned_model(q) == *zoned_model; > drivers/md/dm-table.c: return q && blk_queue_zone_sectors(q) == *zone_sectors; > drivers/md/dm-table.c: return q && (q->queue_flags & flush); > drivers/md/dm-table.c: return q && blk_queue_nonrot(q); > drivers/md/dm-table.c: return q && !blk_queue_add_random(q); > drivers/md/dm-table.c: return q && !q->limits.max_write_same_sectors; > drivers/md/dm-table.c: return q && !q->limits.max_write_zeroes_sectors; > drivers/md/dm-table.c: return q && !blk_queue_discard(q); > drivers/md/dm-table.c: return q && !blk_queue_secure_erase(q); > drivers/md/dm-table.c: return q && bdi_cap_stable_pages_required(q->backing_dev_info); > > I'm fine with however you'd like to skin this cat though. > > Just let me know and I'll keep/drop this patch accordingly. Ok, since you've already got it queued, and there are no other required "if (!dax_dev)" fixups go ahead with what you have. Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx> I just reserve the right to go push it down a level if the kernel ever grows more dax_synchronous() users that do that safety check.
