commit 3c2f83d8bcbedeb89efcaf55ae64a99dce9d7e34 Author: Ming Lei Date: Fri Oct 12 15:53:10 2018 +0800 block: don't deal with discard limit in blkdev_issue_discard() BugLink: https://bugs.launchpad.net/bugs/1836802 commit 744889b7cbb56a64f957e65ade7cb65fe3f35714 upstream. blk_queue_split() does respect this limit via bio splitting, so no need to do that in blkdev_issue_discard(), then we can align to normal bio submit(bio_add_page() & submit_bio()). More importantly, this patch fixes one issue introduced in a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks"), in which zero discard bio may be generated in case of zero alignment. Fixes: a22c4d7e34402ccdf3 ("block: re-add discard_granularity and alignment checks") Cc: stable@vger.kernel.org Cc: Ming Lin Cc: Mike Snitzer Cc: Christoph Hellwig Cc: Xiao Ni Tested-by: Mariusz Dabrowski Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andrea Righi Signed-off-by: Khalid Elmously diff --git a/block/blk-lib.c b/block/blk-lib.c index 2bc544ce3d2e..874df58f7cb5 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -29,9 +29,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, { struct request_queue *q = bdev_get_queue(bdev); struct bio *bio = *biop; - unsigned int granularity; unsigned int op; - int alignment; sector_t bs_mask; if (!q) @@ -51,30 +49,11 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, if ((sector | nr_sects) & bs_mask) return -EINVAL; - /* Zero-sector (unknown) and one-sector granularities are the same. */ - granularity = max(q->limits.discard_granularity >> 9, 1U); - alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; - while (nr_sects) { - unsigned int req_sects; - sector_t end_sect, tmp; - - /* Make sure bi_size doesn't overflow */ - req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); + unsigned int req_sects = nr_sects; + sector_t end_sect; - /** - * If splitting a request, and the next starting sector would be - * misaligned, stop the discard at the previous aligned sector. - */ end_sect = sector + req_sects; - tmp = end_sect; - if (req_sects < nr_sects && - sector_div(tmp, granularity) != alignment) { - end_sect = end_sect - alignment; - sector_div(end_sect, granularity); - end_sect = end_sect * granularity + alignment; - req_sects = end_sect - sector; - } bio = next_bio(bio, 0, gfp_mask); bio->bi_iter.bi_sector = sector;