block: reinstate early return of -EOPNOTSUPP from blkdev_issue_discard
Commit 38f25255330 ("block: add __blkdev_issue_discard") incorrectly
disallowed the early return of -EOPNOTSUPP if the device doesn't support
discard (or secure discard). This early return of -EOPNOTSUPP has
always been part of blkdev_issue_discard() interface so there isn't a
good reason to break that behaviour -- especially when it can be easily
reinstated.
The nuance of allowing early return of -EOPNOTSUPP vs disallowing late
return of -EOPNOTSUPP is: if the overall device never advertised support
for discards and one is issued to the device it is beneficial to inform
the caller that discards are not supported via -EOPNOTSUPP. But if a
device advertises discard support it means that at least a subset of the
device does have discard support -- but it could be that discards issued
to some regions of a stacked device will not be supported. In that case
the late return of -EOPNOTSUPP must be disallowed.
Fixes: 38f25255330 ("block: add __blkdev_issue_discard")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-lib.c b/block/blk-lib.c
index ccbce2b..23d7f30 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -109,11 +109,14 @@
blk_start_plug(&plug);
ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, type,
&bio);
- if (!ret && bio)
+ if (!ret && bio) {
ret = submit_bio_wait(type, bio);
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ }
blk_finish_plug(&plug);
- return ret != -EOPNOTSUPP ? ret : 0;
+ return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);