From patchwork Wed Feb 3 14:24:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 1435396 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=dUgHpkDh; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4DW3w501Qgz9tT8 for ; Thu, 4 Feb 2021 01:29:09 +1100 (AEDT) Received: from localhost ([::1]:58708 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l7J9W-0001gy-T1 for incoming@patchwork.ozlabs.org; Wed, 03 Feb 2021 09:29:06 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46304) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l7J5g-0005Tr-0L for qemu-devel@nongnu.org; Wed, 03 Feb 2021 09:25:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25588) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l7J5e-0000Eh-7N for qemu-devel@nongnu.org; Wed, 03 Feb 2021 09:25:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612362305; 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=pXB/BfjzR1YQKH5VA9RWBG+vnBSdnOEwWoOO4quYZnA=; b=dUgHpkDhEVjI/jkT0vmSrba9iYOFXqpw67C7lIRAon8OUpHrI/ZTMjpnBqc/ArCwPsez6B 15+sU2bo85oZg0vBfsdEry9OeVgwwmo+f0raJ8miL7APi01God5d97ETpNguWIkAbRdrzv 6cgGgfLDJenD78lS0cXaUznZ5hzOObA= 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-195-TgUXKPF8M5qpoLuc4a91kw-1; Wed, 03 Feb 2021 09:25:03 -0500 X-MC-Unique: TgUXKPF8M5qpoLuc4a91kw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 64B6B19611A2; Wed, 3 Feb 2021 14:25:01 +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 81B2719C59; Wed, 3 Feb 2021 14:24:57 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PULL v2 05/20] block/io: refactor bdrv_pad_request(): move bdrv_pad_request() up Date: Wed, 3 Feb 2021 08:24:21 -0600 Message-Id: <20210203142436.703098-6-eblake@redhat.com> In-Reply-To: <20210203142436.703098-1-eblake@redhat.com> References: <20210203142436.703098-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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 Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.539, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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+incoming=patchwork.ozlabs.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 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) 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); }