On 10/12/18 9:53 AM, Ming Lei wrote:
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: Mariusz Dabrowski mariusz.dabrowski@intel.com Cc: Ming Lin ming.l@ssi.samsung.com Cc: Mike Snitzer snitzer@redhat.com Cc: Christoph Hellwig hch@lst.de Cc: Xiao Ni xni@redhat.com Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-lib.c | 28 ++-------------------------- 1 file changed, 2 insertions(+), 26 deletions(-)
diff --git a/block/blk-lib.c b/block/blk-lib.c index d1b9dd03da25..bbd44666f2b5 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) @@ -54,38 +52,16 @@ 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;
unsigned int req_sects = nr_sects;sector_t end_sect;
/** Issue in chunks of the user defined max discard setting,* ensuring that bi_size doesn't overflow*/req_sects = min_t(sector_t, nr_sects,q->limits.max_discard_sectors);
/** If splitting a request, and the next starting sector would be* misaligned, stop the discard at the previous aligned sector.*/tmp = end_sect;if (req_sects < nr_sects &§or_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;
Tested-by: Mariusz Dabrowski mariusz.dabrowski@intel.com
Regards, Mariusz