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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 49004C433DB for ; Tue, 2 Feb 2021 22:54:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B874E64F6A for ; Tue, 2 Feb 2021 22:54:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B874E64F6A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40600 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l74Yr-0001y9-OE for qemu-devel@archiver.kernel.org; Tue, 02 Feb 2021 17:54:17 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40302) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l74Qi-0007SA-90 for qemu-devel@nongnu.org; Tue, 02 Feb 2021 17:45:54 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:39358) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l74Qa-0005rP-Pr for qemu-devel@nongnu.org; Tue, 02 Feb 2021 17:45:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612305944; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AjWp062lj1SotM/eEnEpsQzhzjDP0JGbDkCiWNkEbTU=; b=aCb7D9P+pAngiUi9sk0XFS74SumkaVFmleGp53uMQB27Ry+h+bGrbind2lSw7vCWFxLwYM rGIzhnq+RwQFRkUJgmrN3Lau2FssO2GJg4Zx1uZXHh5Rj514CEdF5uu/3Ja33mOgHzHG2Q fhqxxzagbJEkCYSA9FeWvpBTlPA5HeU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-386-Xd7f1T0ENp-i_sbhfZ5-yA-1; Tue, 02 Feb 2021 17:45:40 -0500 X-MC-Unique: Xd7f1T0ENp-i_sbhfZ5-yA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D71A4804022; Tue, 2 Feb 2021 22:45:38 +0000 (UTC) Received: from blue.redhat.com (ovpn-112-103.phx2.redhat.com [10.3.112.103]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4A05310016F5; Tue, 2 Feb 2021 22:45:38 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PULL 05/20] block/io: refactor bdrv_pad_request(): move bdrv_pad_request() up Date: Tue, 2 Feb 2021 16:45:14 -0600 Message-Id: <20210202224529.642055-6-eblake@redhat.com> In-Reply-To: <20210202224529.642055-1-eblake@redhat.com> References: <20210202224529.642055-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=63.128.21.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.386, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , Kevin Wolf , Vladimir Sementsov-Ogievskiy , "open list:Block I/O path" , Max Reitz , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy Prepare for the following patch when bdrv_pad_request() will be able to fail. Update the comments. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20201211183934.169161-5-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake [eblake: grammar tweak] Signed-off-by: Eric Blake --- block/io.c | 25 +++++++++++++++++++------ block/io.c.rej | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+), 6 deletions(-) create mode 100644 block/io.c.rej diff --git a/block/io.c b/block/io.c index c8c9dea55466..3b1aec366ede 100644 --- a/block/io.c +++ b/block/io.c @@ -2135,6 +2135,7 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, uint64_t align = bs->bl.request_alignment; BdrvRequestPadding pad; int ret; + bool padded = false; trace_bdrv_co_pwritev(child->bs, offset, bytes, flags); @@ -2166,20 +2167,32 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, return 0; } + if (!(flags & BDRV_REQ_ZERO_WRITE)) { + /* + * Pad request for following read-modify-write cycle. + * bdrv_co_do_zero_pwritev() does aligning by itself, so, we do + * alignment only if there is no ZERO flag. + */ + padded = bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, + &pad); + } + bdrv_inc_in_flight(bs); - /* - * Align write if necessary by performing a read-modify-write cycle. - * Pad qiov with the read parts and be sure to have a tracked request not - * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle. - */ tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_WRITE); if (flags & BDRV_REQ_ZERO_WRITE) { + assert(!padded); ret = bdrv_co_do_zero_pwritev(child, offset, bytes, flags, &req); goto out; } - if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) { + if (padded) { + /* + * Request was unaligned to request_alignment and therefore + * padded. We are going to do read-modify-write, and must + * serialize the request to prevent interactions of the + * widened region with other transactions. + */ bdrv_make_request_serialising(&req, align); bdrv_padding_rmw_read(child, &req, &pad, false); } diff --git a/block/io.c.rej b/block/io.c.rej new file mode 100644 index 000000000000..f52df016263b --- /dev/null +++ b/block/io.c.rej @@ -0,0 +1,40 @@ +diff a/block/io.c b/block/io.c (rejected hunks) +@@ -2138,20 +2139,32 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child, + return 0; + } + ++ if (!(flags & BDRV_REQ_ZERO_WRITE)) { ++ /* ++ * Pad request for following read-modify-write cycle. ++ * bdrv_co_do_zero_pwritev() does aligning by itself, so, we do ++ * alignment only if there is no ZERO flag. ++ */ ++ padded = bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, ++ &pad); ++ } ++ + bdrv_inc_in_flight(bs); +- /* +- * Align write if necessary by performing a read-modify-write cycle. +- * Pad qiov with the read parts and be sure to have a tracked request not +- * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle. +- */ + tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_WRITE); + + if (flags & BDRV_REQ_ZERO_WRITE) { ++ assert(!padded); + ret = bdrv_co_do_zero_pwritev(child, offset, bytes, flags, &req); + goto out; + } + +- if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) { ++ if (padded) { ++ /* ++ * Request was unaligned to request_alignment and therefore padded. ++ * We are going to do read-modify-write. User is not prepared to widened ++ * request intersections with other requests, so we serialize the ++ * request. ++ */ + bdrv_mark_request_serialising(&req, align); + bdrv_padding_rmw_read(child, &req, &pad, false); + } -- 2.30.0