Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592AbbHEIvn (ORCPT ); Wed, 5 Aug 2015 04:51:43 -0400 Received: from blu004-omc1s11.hotmail.com ([65.55.116.22]:50845 "EHLO BLU004-OMC1S11.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278AbbHEIvi (ORCPT ); Wed, 5 Aug 2015 04:51:38 -0400 X-TMN: [SiUgWrkUOc/OhkQgfBtp2ytEVVcpo0OA64TUYWUo/Sw=] X-Originating-Email: [wanpeng.li@hotmail.com] Message-ID: From: Wanpeng Li To: Jens Axboe CC: linux-kernel@vger.kernel.org, Wanpeng Li Subject: [PATCH] block: fix update first/last mergeable segment sizes Date: Wed, 5 Aug 2015 16:51:16 +0800 X-Mailer: git-send-email 1.9.1 X-OriginalArrivalTime: 05 Aug 2015 08:51:36.0361 (UTC) FILETIME=[EFA9F190:01D0CF5B] MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2360 Lines: 60 To keep track of the max segment size, the sizes of the first and last mergeable segments in the bio are accounted, prev->bio->bi_seg_front_size and next->biotail->bi_seg_back_size will be updated if blk_phys_contig_segment is true, however, there are still some scenarios such like nonconsistent blk integrity which leads to merge fail, in addtion, futher merge fail is incurred due to bio->bi_seg_back_size + next->bi_seg_front_size > queue_max_segment_size(q) check in function blk_phys_contig_segment(). This patch fix it by updating first/last mergeable segments size iff all the conditions of merging are meet. Signed-off-by: Wanpeng Li --- block/blk-merge.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 30a0d9f..7e7bda4 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -367,6 +367,7 @@ static int req_gap_to_prev(struct request *req, struct request *next) static int ll_merge_requests_fn(struct request_queue *q, struct request *req, struct request *next) { + bool update_segment_size = false; int total_phys_segments; unsigned int seg_size = req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; @@ -391,10 +392,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; if (blk_phys_contig_segment(q, req->biotail, next->bio)) { - if (req->nr_phys_segments == 1) - req->bio->bi_seg_front_size = seg_size; - if (next->nr_phys_segments == 1) - next->biotail->bi_seg_back_size = seg_size; + update_segment_size = true; total_phys_segments--; } @@ -405,6 +403,12 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, return 0; /* Merge is OK... */ + if (update_segment_size) { + if (req->nr_phys_segments == 1) + req->bio->bi_seg_front_size = seg_size; + if (next->nr_phys_segments == 1) + next->biotail->bi_seg_back_size = seg_size; + } req->nr_phys_segments = total_phys_segments; return 1; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/