From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukas Czerner Subject: [PATCH 3/3] blkdev: honor discard_granularity in blkdev_issue_discard() Date: Mon, 2 May 2011 16:17:21 +0200 Message-ID: <1304345841-20063-3-git-send-email-lczerner@redhat.com> References: <1304345841-20063-1-git-send-email-lczerner@redhat.com> Cc: linux-kernel@vger.kernel.org, Lukas Czerner , Dmitry Monakhov , Jens Axboe To: linux-fsdevel@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:12442 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758655Ab1EBOSm (ORCPT ); Mon, 2 May 2011 10:18:42 -0400 In-Reply-To: <1304345841-20063-1-git-send-email-lczerner@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: As Jeff Moyer pointed out we do not honor discard granularity while submitting REQ_DISCARD bios of size smaller than max_discard_sectors. That fact might have unwanted consequences of device ignoring the request, or even worse if device firmware is buggy. This commit changes the behaviour so all discard bios smaller than max_discard_sectors are aligned properly wrt discard_granularity. Signed-off-by: Lukas Czerner Reported-by: Jeff Moyer CC: Dmitry Monakhov CC: Jens Axboe --- block/blk-lib.c | 10 ++++------ 1 files changed, 4 insertions(+), 6 deletions(-) diff --git a/block/blk-lib.c b/block/blk-lib.c index d7a98d3..4019036 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -46,7 +46,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, DECLARE_COMPLETION_ONSTACK(wait); struct request_queue *q = bdev_get_queue(bdev); int type = REQ_WRITE | REQ_DISCARD; - unsigned int max_discard_sectors; + unsigned int max_discard_sectors, disc_sects; struct bio_batch bb; struct bio *bio; int ret = 0; @@ -57,16 +57,14 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, if (!blk_queue_discard(q)) return -EOPNOTSUPP; + disc_sects = q->limits.discard_granularity >> 9; /* * Ensure that max_discard_sectors is of the proper * granularity */ max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); - if (q->limits.discard_granularity) { - unsigned int disc_sects = q->limits.discard_granularity >> 9; - + if (q->limits.discard_granularity) max_discard_sectors &= ~(disc_sects - 1); - } if (flags & BLKDEV_DISCARD_SECURE) { if (!blk_queue_secdiscard(q)) @@ -95,7 +93,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, nr_sects -= max_discard_sectors; sector += max_discard_sectors; } else { - bio->bi_size = nr_sects << 9; + bio->bi_size = ((nr_sects & ~(disc_sects - 1)) << 9); nr_sects = 0; } -- 1.7.4.4