| Message ID | 20190214091930.121952-1-yangerkun@huawei.com (mailing list archive) |
|---|---|
| State | Rejected, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | dm: clear BIO_SEG_VALID in clone_bio | expand |
On Thu, Feb 14 2019 at 4:19am -0500, yangerkun <yangerkun@huawei.com> wrote: > Since 57c36519e4("dm: fix clone_bio() to trigger blk_recount_segments()") > has been reverted by fa8db494("dm: don't use bio_trim() afterall"), the > problem that clone bio won't trigger blk_recount_segments will exits > again. So just clean the flag in clone_bio. > > Fixes: fa8db4948f522("dm: don't use bio_trim() afterall") > Signed-off-by: yangerkun <yangerkun@huawei.com> > --- > drivers/md/dm.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 515e6af..b22ac04 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -1336,6 +1336,7 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio, > return r; > } > > + bio_clear_flag(clone, BIO_SEG_VALID); > bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector)); > clone->bi_iter.bi_size = to_bytes(len); > > -- > 2.9.5 > Yes, when I wrote commit fa8db4948f522 I purposely did _not_ clear BIO_SEG_VALID. Commit 57c36519e4 wasn't born out of an observed need to blk_recount_segments() (e.g. otherwise something would fail). So I just reverted to what DM has done in clone_bio() for quite a long time once using bio_trim() became a liability (since fixed in dm-crypt, but not staged upstream yet). Anyway: I'm open to reconsidering, by taking your patch, if there is a genuine benefit/fix associated with triggering blk_recount_segments() for clones. I'm unaware of why it's needed... Mike -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
Hi, Mike Snitzer wrote on 2019/2/15 2:55: > On Thu, Feb 14 2019 at 4:19am -0500, > yangerkun <yangerkun@huawei.com> wrote: > >> Since 57c36519e4("dm: fix clone_bio() to trigger blk_recount_segments()") >> has been reverted by fa8db494("dm: don't use bio_trim() afterall"), the >> problem that clone bio won't trigger blk_recount_segments will exits >> again. So just clean the flag in clone_bio. >> >> Fixes: fa8db4948f522("dm: don't use bio_trim() afterall") >> Signed-off-by: yangerkun <yangerkun@huawei.com> >> --- >> drivers/md/dm.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/md/dm.c b/drivers/md/dm.c >> index 515e6af..b22ac04 100644 >> --- a/drivers/md/dm.c >> +++ b/drivers/md/dm.c >> @@ -1336,6 +1336,7 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio, >> return r; >> } >> >> + bio_clear_flag(clone, BIO_SEG_VALID); >> bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector)); >> clone->bi_iter.bi_size = to_bytes(len); >> >> -- >> 2.9.5 >> > > Yes, when I wrote commit fa8db4948f522 I purposely did _not_ clear > BIO_SEG_VALID. Commit 57c36519e4 wasn't born out of an observed need to > blk_recount_segments() (e.g. otherwise something would fail). > > So I just reverted to what DM has done in clone_bio() for quite a long > time once using bio_trim() became a liability (since fixed in dm-crypt, > but not staged upstream yet). > > Anyway: I'm open to reconsidering, by taking your patch, if there is a > genuine benefit/fix associated with triggering blk_recount_segments() > for clones. I'm unaware of why it's needed... Re-read the code, clone_bio won't copy flags from source bio, so the flag bio_clear_flag of clone won't set anyway. So no need for this patch, Right? Thanks, Kun. > > Mike > > . > -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 515e6af..b22ac04 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1336,6 +1336,7 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio, return r; } + bio_clear_flag(clone, BIO_SEG_VALID); bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector)); clone->bi_iter.bi_size = to_bytes(len);
Since 57c36519e4("dm: fix clone_bio() to trigger blk_recount_segments()") has been reverted by fa8db494("dm: don't use bio_trim() afterall"), the problem that clone bio won't trigger blk_recount_segments will exits again. So just clean the flag in clone_bio. Fixes: fa8db4948f522("dm: don't use bio_trim() afterall") Signed-off-by: yangerkun <yangerkun@huawei.com> --- drivers/md/dm.c | 1 + 1 file changed, 1 insertion(+)