4.18-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka mpatocka@redhat.com
commit b88aef36b87c9787a4db724923ec4f57dfd513f3 upstream.
If __blkdev_issue_discard is in progress and a device mapper device is reloaded with a table that doesn't support discard, q->limits.max_discard_sectors is set to zero. This results in infinite loop in __blkdev_issue_discard.
This patch checks if max_discard_sectors is zero and aborts with -EOPNOTSUPP.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Tested-by: Zdenek Kabelac mpatocka@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- block/blk-lib.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -68,6 +68,8 @@ int __blkdev_issue_discard(struct block_ */ req_sects = min_t(sector_t, nr_sects, q->limits.max_discard_sectors); + if (!req_sects) + goto fail; if (req_sects > UINT_MAX >> 9) req_sects = UINT_MAX >> 9;
@@ -105,6 +107,14 @@ int __blkdev_issue_discard(struct block_
*biop = bio; return 0; + +fail: + if (bio) { + submit_bio_wait(bio); + bio_put(bio); + } + *biop = NULL; + return -EOPNOTSUPP; } EXPORT_SYMBOL(__blkdev_issue_discard);