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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 58885C43441 for ; Thu, 8 Nov 2018 22:22:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F65C20818 for ; Thu, 8 Nov 2018 22:22:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Np2dOVEU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F65C20818 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728755AbeKIH7r (ORCPT ); Fri, 9 Nov 2018 02:59:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:35350 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731715AbeKIHnF (ORCPT ); Fri, 9 Nov 2018 02:43:05 -0500 Received: from localhost (unknown [208.72.13.198]) (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 3B4FB21486; Thu, 8 Nov 2018 22:05:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541714735; bh=2LXqvFmSSn6Z59FYDKX3dxJbaMFBhvXkajughPQxPZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Np2dOVEU5LXMMjZUre4WgDMZP7ze1HjVLjLUYfmLM9J9XFbO45Gno45X3ogCinwpP /I+U3j8FlIyBv05OZ4J9Sr5mFCXFN63u6maieiuBiKieDpSzj+EoU73QAEolWfNRms 5VPVC69/OFxh7+g5dcQYOtmB2yOCtX1Xspczju4E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josef Bacik , Jens Axboe , Sasha Levin Subject: [PATCH 4.9 096/171] nbd: only set MSG_MORE when we have more to send Date: Thu, 8 Nov 2018 13:51:06 -0800 Message-Id: <20181108215134.445993898@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181108215127.257643509@linuxfoundation.org> References: <20181108215127.257643509@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit d61b7f972dab2a7d187c38254845546dfc8eed85 ] A user noticed that write performance was horrible over loopback and we traced it to an inversion of when we need to set MSG_MORE. It should be set when we have more bvec's to send, not when we are on the last bvec. This patch made the test go from 20 iops to 78k iops. Signed-off-by: Josef Bacik Fixes: 429a787be679 ("nbd: fix use-after-free of rq/bio in the xmit path") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/nbd.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 4d30da269060..42a53956aefe 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -269,7 +269,7 @@ static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd) { struct request *req = blk_mq_rq_from_pdu(cmd); - int result, flags; + int result; struct nbd_request request; unsigned long size = blk_rq_bytes(req); struct bio *bio; @@ -309,7 +309,6 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd) if (type != NBD_CMD_WRITE) return 0; - flags = 0; bio = req->bio; while (bio) { struct bio *next = bio->bi_next; @@ -318,9 +317,8 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd) bio_for_each_segment(bvec, bio, iter) { bool is_last = !next && bio_iter_last(bvec, iter); + int flags = is_last ? 0 : MSG_MORE; - if (is_last) - flags = MSG_MORE; dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", cmd, bvec.bv_len); result = sock_send_bvec(nbd, &bvec, flags); -- 2.17.1