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authorMike Snitzer <snitzer@redhat.com>2015-05-22 09:14:03 -0400
committerJens Axboe <axboe@fb.com>2015-05-22 08:58:55 -0600
commit326e1dbb57368087a36607aaebe9795b8d5453e5 (patch)
treebbc17b38188d4f2d45d255f1254d63494d37e1e4 /drivers
parentb04a5636a665f5529fdf69ee7e5512156196f31c (diff)
block: remove management of bi_remaining when restoring original bi_end_io
Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains") regressed all existing callers that followed this pattern: 1) saving a bio's original bi_end_io 2) wiring up an intermediate bi_end_io 3) restoring the original bi_end_io from intermediate bi_end_io 4) calling bio_endio() to execute the restored original bi_end_io The regression was due to BIO_CHAIN only ever getting set if bio_inc_remaining() is called. For the above pattern it isn't set until step 3 above (step 2 would've needed to establish BIO_CHAIN). As such the first bio_endio(), in step 2 above, never decremented __bi_remaining before calling the intermediate bi_end_io -- leaving __bi_remaining with the value 1 instead of 0. When bio_inc_remaining() occurred during step 3 it brought it to a value of 2. When the second bio_endio() was called, in step 4 above, it should've called the original bi_end_io but it didn't because there was an extra reference that wasn't dropped (due to atomic operations being optimized away since BIO_CHAIN wasn't set upfront). Fix this issue by removing the __bi_remaining management complexity for all callers that use the above pattern -- bio_chain() is the only interface that _needs_ to be concerned with __bi_remaining. For the above pattern callers just expect the bi_end_io they set to get called! Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls that aren't associated with the bio_chain() interface. Also, the bio_inc_remaining() interface has been moved local to bio.c. Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/bcache/io.c2
-rw-r--r--drivers/md/dm-cache-target.c6
-rw-r--r--drivers/md/dm-raid1.c2
-rw-r--r--drivers/md/dm-snap.c1
-rw-r--r--drivers/md/dm-thin.c9
-rw-r--r--drivers/md/dm-verity.c2
6 files changed, 5 insertions, 17 deletions
diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index fa028fa82df4..cb64e64a4789 100644
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -55,7 +55,7 @@ static void bch_bio_submit_split_done(struct closure *cl)
s->bio->bi_end_io = s->bi_end_io;
s->bio->bi_private = s->bi_private;
- bio_endio_nodec(s->bio, 0);
+ bio_endio(s->bio, 0);
closure_debug_destroy(&s->cl);
mempool_free(s, s->p->bio_split_hook);
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 705eb7b99d69..41b2594a80c6 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -86,12 +86,6 @@ static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio)
{
bio->bi_end_io = h->bi_end_io;
bio->bi_private = h->bi_private;
-
- /*
- * Must bump bi_remaining to allow bio to complete with
- * restored bi_end_io.
- */
- bio_inc_remaining(bio);
}
/*----------------------------------------------------------------*/
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index d6a1c096b777..743fa9bbae9e 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1254,8 +1254,6 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
dm_bio_restore(bd, bio);
bio_record->details.bi_bdev = NULL;
- bio_inc_remaining(bio);
-
queue_bio(ms, bio, rw);
return DM_ENDIO_INCOMPLETE;
}
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 8bfeae218531..7c82d3ccce87 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1478,7 +1478,6 @@ out:
if (full_bio) {
full_bio->bi_end_io = pe->full_bio_end_io;
full_bio->bi_private = pe->full_bio_private;
- bio_inc_remaining(full_bio);
}
increment_pending_exceptions_done_count();
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 342dbdad6131..e852602c0091 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -793,10 +793,9 @@ static void inc_remap_and_issue_cell(struct thin_c *tc,
static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
{
- if (m->bio) {
+ if (m->bio)
m->bio->bi_end_io = m->saved_bi_end_io;
- bio_inc_remaining(m->bio);
- }
+
cell_error(m->tc->pool, m->cell);
list_del(&m->list);
mempool_free(m, m->tc->pool->mapping_pool);
@@ -810,10 +809,8 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
int r;
bio = m->bio;
- if (bio) {
+ if (bio)
bio->bi_end_io = m->saved_bi_end_io;
- bio_inc_remaining(bio);
- }
if (m->err) {
cell_error(pool, m->cell);
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 66616db33e6f..bb9c6a00e4b0 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -459,7 +459,7 @@ static void verity_finish_io(struct dm_verity_io *io, int error)
bio->bi_end_io = io->orig_bi_end_io;
bio->bi_private = io->orig_bi_private;
- bio_endio_nodec(bio, error);
+ bio_endio(bio, error);
}
static void verity_work(struct work_struct *w)