From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752942AbbKXCgn (ORCPT ); Mon, 23 Nov 2015 21:36:43 -0500 Received: from mail-pa0-f68.google.com ([209.85.220.68]:35039 "EHLO mail-pa0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752360AbbKXCg1 (ORCPT ); Mon, 23 Nov 2015 21:36:27 -0500 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, Christoph Hellwig , Michael Ellerman , Laurent Dufour , Mark Salter , Hannes Reinecke , Pratyush Anand , Ming Lei Subject: [PATCH 3/3] blk-merge: warn if figured out segment number is bigger than nr_phys_segments Date: Tue, 24 Nov 2015 10:35:31 +0800 Message-Id: <1448332531-10704-4-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1448332531-10704-1-git-send-email-ming.lei@canonical.com> References: <1448332531-10704-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We had seen lots of reports of this kind issue, so add one warnning in blk-merge, then it can be triggered easily and avoid to depend on warning/bug from drivers. Signed-off-by: Ming Lei --- block/blk-merge.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/blk-merge.c b/block/blk-merge.c index 50793cd..41a55ba 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -428,6 +428,12 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, if (sg) sg_mark_end(sg); + /* + * Something must have been wrong if the figured number of + * segment is bigger than number of req's physical segments + */ + WARN_ON(nsegs > rq->nr_phys_segments); + return nsegs; } EXPORT_SYMBOL(blk_rq_map_sg); -- 1.9.1