Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S942896AbcJ2ION (ORCPT ); Sat, 29 Oct 2016 04:14:13 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:34433 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941516AbcJ2INS (ORCPT ); Sat, 29 Oct 2016 04:13:18 -0400 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , "Kirill A . Shutemov" , Ming Lei , Alexander Viro Subject: [PATCH 19/60] fs/buffer: comment on direct access to bvec table Date: Sat, 29 Oct 2016 16:08:18 +0800 Message-Id: <1477728600-12938-20-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> References: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 798 Lines: 26 Signed-off-by: Ming Lei --- fs/buffer.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/buffer.c b/fs/buffer.c index b205a629001d..81c3793948b4 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -3018,8 +3018,13 @@ static void end_bio_bh_io_sync(struct bio *bio) void guard_bio_eod(int op, struct bio *bio) { sector_t maxsector; - struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; unsigned truncated_bytes; + /* + * It is safe to truncate the last bvec in the following way + * even though multipage bvec is supported, but we need to + * fix the parameters passed to zero_user(). + */ + struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9; if (!maxsector) -- 2.7.4