From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f198.google.com (mail-qt0-f198.google.com [209.85.216.198]) by kanga.kvack.org (Postfix) with ESMTP id D4ECA6B02F4 for ; Tue, 8 Aug 2017 04:47:07 -0400 (EDT) Received: by mail-qt0-f198.google.com with SMTP id u19so12584628qtc.14 for ; Tue, 08 Aug 2017 01:47:07 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id n66si757862qkd.434.2017.08.08.01.47.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Aug 2017 01:47:07 -0700 (PDT) From: Ming Lei Subject: [PATCH v3 05/49] fs/buffer: comment on direct access to bvec table Date: Tue, 8 Aug 2017 16:45:04 +0800 Message-Id: <20170808084548.18963-6-ming.lei@redhat.com> In-Reply-To: <20170808084548.18963-1-ming.lei@redhat.com> References: <20170808084548.18963-1-ming.lei@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jens Axboe , Christoph Hellwig , Huang Ying , Andrew Morton , Alexander Viro Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Ming Lei 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 5715dac7821f..c821ed6a6f0e 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -3054,8 +3054,13 @@ 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) -- 2.9.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org