hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9K0H3

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In __blkdev_issue_discard(), q->limits.discard_granularity is read multi times.

WARN_ON_ONCE(!q->limits.discard_granularity) [1] ... q->limits.discard_granularity >> SECTOR_SHIFT [2] ... bio_aligned_discard_max_sectors [3]

It can be changed to 0 after check [1], such as submitting ioctl 'LOOP_SET_STATUS'. This is undesirable. If 'discard_granularity' is set to 0, BUG_ON might be triggered and the loop of 'while(nr_sects)' will never exit(see fixes commit). Fix it by checking 'req_sects' before submit io, return error code directly if it is 0.

Fixes: b35fd7422c2f ("block: check queue's limits.discard_granularity in __blkdev_issue_discard()") Signed-off-by: Li Nan linan122@huawei.com --- block/blk-lib.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c index e90614fd8d6a..59ff99bc4698 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -27,7 +27,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, struct bio **biop) { struct request_queue *q = bdev_get_queue(bdev); - struct bio *bio = *biop; + struct bio *bio = NULL; unsigned int op; sector_t bs_mask, part_offset = 0;

@@ -92,6 +92,17 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, req_sects = min_t(sector_t, nr_sects, granularity_aligned_lba - sector_mapped);

+ if (!req_sects) { + /* just put the bio allocated in this function */ + if (bio) { + bio_io_error(bio); + bio_put(bio); + } + return -EOPNOTSUPP; + } + if (!bio) + bio = *biop; + WARN_ON_ONCE((req_sects << 9) > UINT_MAX);

bio = blk_next_bio(bio, 0, gfp_mask);