From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:55518 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726789AbeJLPYe (ORCPT ); Fri, 12 Oct 2018 11:24:34 -0400 From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , stable@vger.kernel.org, Mariusz Dabrowski , Ming Lin , Mike Snitzer , Christoph Hellwig , Xiao Ni Subject: [PATCH] block: don't deal with discard limit in blkdev_issue_discard() Date: Fri, 12 Oct 2018 15:53:10 +0800 Message-Id: <20181012075310.4587-1-ming.lei@redhat.com> Sender: stable-owner@vger.kernel.org List-ID: 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 Cc: Ming Lin Cc: Mike Snitzer Cc: Christoph Hellwig Cc: Xiao Ni Signed-off-by: Ming Lei --- 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 (!req_sects) goto fail; if (req_sects > UINT_MAX >> 9) req_sects = UINT_MAX >> 9; - /* - * 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; -- 2.9.5