Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753115AbcCLO4f (ORCPT ); Sat, 12 Mar 2016 09:56:35 -0500 Received: from mail-ob0-f178.google.com ([209.85.214.178]:35823 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751814AbcCLO4d (ORCPT ); Sat, 12 Mar 2016 09:56:33 -0500 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, Christoph Hellwig , Sagi Grimberg , Kent Overstreet , Ming Lei , stable@vger.kernel.org Subject: [PATCH] block: don't optimize for non-cloned bio in bio_get_last_bvec() Date: Sat, 12 Mar 2016 22:56:19 +0800 Message-Id: <1457794579-6125-1-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1137 Lines: 36 For !BIO_CLONED bio, we can use .bi_vcnt safely, but it doesn't mean we can just simply return .bi_io_vec[.bi_vcnt - 1] because the start postion may have been moved in the middle of the bvec, such as splitting in the middle of bvec. Fixes: 7bcd79ac50d9(block: bio: introduce helpers to get the 1st and last bvec) Cc: stable@vger.kernel.org Reported-by: Kent Overstreet Signed-off-by: Ming Lei --- Jens, I am fine with either reverting previous patchset or applying this one to v4.5, and you decide it. Thanks Kent for reporting the issue! include/linux/bio.h | 5 ----- 1 file changed, 5 deletions(-) diff --git a/include/linux/bio.h b/include/linux/bio.h index 1e7248f..4abc129 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -267,11 +267,6 @@ static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv) struct bvec_iter iter = bio->bi_iter; int idx; - if (!bio_flagged(bio, BIO_CLONED)) { - *bv = bio->bi_io_vec[bio->bi_vcnt - 1]; - return; - } - if (unlikely(!bio_multiple_segments(bio))) { *bv = bio_iovec(bio); return; -- 1.9.1