From bbd848e0fade51ae51dab86a0683069cef89953f Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 5 May 2016 11:54:21 -0400 Subject: [PATCH] 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 Signed-off-by: Jens Axboe --- block/blk-lib.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block/blk-lib.c b/block/blk-lib.c index ccbce2b2ea05..23d7f301a196 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -109,11 +109,14 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 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); -- 2.20.1