From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1E97C433E7 for ; Tue, 1 Sep 2020 16:28:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF65220E65 for ; Tue, 1 Sep 2020 16:28:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598977717; bh=igFLgAPBjGzvMF/y+IQ59KaFgYmVYOPfdPx8ZzrjThA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Jh56HRnLfla8Rj0NiTjrgfSB1b6afgS2VFDkeqTdQefUXn5SpK713lJN5PuALtTpq hjG3R1vcdaJjwsk4K4wR9iUfpx/gxYlXXqjMzGeZkFo/EB0ezpRi2aS0bRHCbyRhoW vjS0NqgpU4cbbePvU1XuWdJCKlwbNcK7QhFJbato= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730985AbgIAQ2f (ORCPT ); Tue, 1 Sep 2020 12:28:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:35438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730834AbgIAPcB (ORCPT ); Tue, 1 Sep 2020 11:32:01 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B7EEE21548; Tue, 1 Sep 2020 15:31:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974320; bh=igFLgAPBjGzvMF/y+IQ59KaFgYmVYOPfdPx8ZzrjThA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mD8oxMFGh/6Fv+u6hOXtR2pinuiL1bSBiDXJAT2xuGTU+VhqeZCSw6B1fg79W3Z01 3ItUGXwiQMeJLAVks/Sil+qMP7YacimHMa+E8PsqxH/kRwmD0ycOR4oeWmjppIzoAG 0+3hjKAA6gUy4xeQYHzYF4eVeUkPjfnSHq3Rb9aw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ming Lei , Christoph Hellwig , Changpeng Liu , Daniel Verkamp , "Michael S. Tsirkin" , Stefan Hajnoczi , Stefano Garzarella , Jens Axboe , Sasha Levin Subject: [PATCH 5.4 100/214] block: virtio_blk: fix handling single range discard request Date: Tue, 1 Sep 2020 17:09:40 +0200 Message-Id: <20200901150957.787929636@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901150952.963606936@linuxfoundation.org> References: <20200901150952.963606936@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ming Lei [ Upstream commit af822aa68fbdf0a480a17462ed70232998127453 ] 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support") starts to support multi-range discard for virtio-blk. However, the virtio-blk disk may report max discard segment as 1, at least that is exactly what qemu is doing. So far, block layer switches to normal request merge if max discard segment limit is 1, and multiple bios can be merged to single segment. This way may cause memory corruption in virtblk_setup_discard_write_zeroes(). Fix the issue by handling single max discard segment in straightforward way. Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support") Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig Cc: Changpeng Liu Cc: Daniel Verkamp Cc: Michael S. Tsirkin Cc: Stefan Hajnoczi Cc: Stefano Garzarella Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/virtio_blk.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c1de270046bfe..2eeb2bcb488d4 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -205,16 +205,31 @@ static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap) if (!range) return -ENOMEM; - __rq_for_each_bio(bio, req) { - u64 sector = bio->bi_iter.bi_sector; - u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; - - range[n].flags = cpu_to_le32(flags); - range[n].num_sectors = cpu_to_le32(num_sectors); - range[n].sector = cpu_to_le64(sector); - n++; + /* + * Single max discard segment means multi-range discard isn't + * supported, and block layer only runs contiguity merge like + * normal RW request. So we can't reply on bio for retrieving + * each range info. + */ + if (queue_max_discard_segments(req->q) == 1) { + range[0].flags = cpu_to_le32(flags); + range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req)); + range[0].sector = cpu_to_le64(blk_rq_pos(req)); + n = 1; + } else { + __rq_for_each_bio(bio, req) { + u64 sector = bio->bi_iter.bi_sector; + u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT; + + range[n].flags = cpu_to_le32(flags); + range[n].num_sectors = cpu_to_le32(num_sectors); + range[n].sector = cpu_to_le64(sector); + n++; + } } + WARN_ON_ONCE(n != segments); + req->special_vec.bv_page = virt_to_page(range); req->special_vec.bv_offset = offset_in_page(range); req->special_vec.bv_len = sizeof(*range) * segments; -- 2.25.1