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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 129D2C54FCB for ; Mon, 27 Apr 2020 14:48:58 +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 BC52720661 for ; Mon, 27 Apr 2020 14:48:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=virtuozzo.com header.i=@virtuozzo.com header.b="iahpMOvM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC52720661 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49128 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jT544-00071D-SB for qemu-devel@archiver.kernel.org; Mon, 27 Apr 2020 10:48:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56890) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jT4v8-0008GE-EJ for qemu-devel@nongnu.org; Mon, 27 Apr 2020 10:39:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jT4v5-0007lY-N0 for qemu-devel@nongnu.org; Mon, 27 Apr 2020 10:39:42 -0400 Received: from mail-eopbgr40124.outbound.protection.outlook.com ([40.107.4.124]:49833 helo=EUR03-DB5-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jT4v2-0007iT-IO; Mon, 27 Apr 2020 10:39:36 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=DaGiq1hvFR483fjKru53lCl9xT3zDWwx5HyuPT20YZ4xrwHs5jjlLuapOKqX2ond2BcJtWU6VdxU7BrpKlU/lfgtLekEbUmQEJYpV7wVqh2QqeSqtu+TPnD0kUxY61oCrrUWyq8DIXTgX3vggbVwM7gE8SUJY3lbtgVkMIIXAEjEZIlLoQDutP887qhVUsdwzGFuntNpjaeQIw9PhL8b5RckyDhMBv4CS9fsDIwtgJzWF0/D6i/VhuWZn7h2P0bN7ZkVbJsNzO10PEEVB/K1BSbW7Cj0Je4UIXx7zJWm3JuXYkXlTt7edIi5C79PRfQRqx0obiD4X/HdXvNjcEyj7Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=9ihRWiLKIJVJgQeWrd0GmjsDZuY3P9UqMYNUt5RqTKw=; b=ZJLrWjRXrwTh1pVFNosHmV41yqboxPpQvIaqOGWttyF58Z84g/jUKAwDVorSJJyi1/UG/wEwt9PvtA2ZOaBvKEJZJMdaMK1ZgDQjtCxNgTa07W1Zq/nawZLvYRTe26QJ4s4QN8rbp3eMnImonAOZntY1n4BAs2H6L4JltrqAYTSwv7dsOrnmeH3GVpoq7INk6NEihxeQQKz1n59GNslt4b+8Tmh7czsPFFkfJT2j17DrBKR2vsSVPVqfJMQPXH7I+gvd3gKg/1/cSbc1UaFjcmtBTUvp/EzDJtwuzODBCTeecqlZs38ErGx3aOKWjZ+Rmd8MSMTwh2TekejsF8UBkw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=virtuozzo.com; dmarc=pass action=none header.from=virtuozzo.com; dkim=pass header.d=virtuozzo.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=virtuozzo.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=9ihRWiLKIJVJgQeWrd0GmjsDZuY3P9UqMYNUt5RqTKw=; b=iahpMOvMVPG4FxTyCbmsvck9AD6ydIbQaOn+OwythTPnjiGDDBDwUeYqg1IgoZDwgyIsct/Sr4J+35OtvtMCz+b8sfmEw7T1rS9uyx6jxeoxv9M4w6C9YRzsVzpyrOGDX7CDP11/mFL5UmMhyi+S0G9vt/JGm2BZ2sYpFYlAr3E= Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=vsementsov@virtuozzo.com; Received: from AM7PR08MB5494.eurprd08.prod.outlook.com (2603:10a6:20b:dc::15) by AM7PR08MB5336.eurprd08.prod.outlook.com (2603:10a6:20b:105::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2937.22; Mon, 27 Apr 2020 14:39:33 +0000 Received: from AM7PR08MB5494.eurprd08.prod.outlook.com ([fe80::acfa:5:88c8:b7b9]) by AM7PR08MB5494.eurprd08.prod.outlook.com ([fe80::acfa:5:88c8:b7b9%3]) with mapi id 15.20.2937.020; Mon, 27 Apr 2020 14:39:33 +0000 From: Vladimir Sementsov-Ogievskiy To: qemu-block@nongnu.org Subject: [PATCH v2 4/9] block/io: move bdrv_rw_co_entry and friends down Date: Mon, 27 Apr 2020 17:39:02 +0300 Message-Id: <20200427143907.5710-5-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200427143907.5710-1-vsementsov@virtuozzo.com> References: <20200427143907.5710-1-vsementsov@virtuozzo.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: FRYP281CA0010.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10::20) To AM7PR08MB5494.eurprd08.prod.outlook.com (2603:10a6:20b:dc::15) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from localhost.localdomain (185.215.60.182) by FRYP281CA0010.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2937.13 via Frontend Transport; Mon, 27 Apr 2020 14:39:33 +0000 X-Mailer: git-send-email 2.21.0 X-Originating-IP: [185.215.60.182] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 3ec3f310-36f2-459f-b11a-08d7eab8cd4c X-MS-TrafficTypeDiagnostic: AM7PR08MB5336: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-Forefront-PRVS: 0386B406AA X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:AM7PR08MB5494.eurprd08.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(4636009)(396003)(376002)(136003)(346002)(366004)(39840400004)(478600001)(52116002)(6916009)(2616005)(956004)(4326008)(8676002)(36756003)(107886003)(6666004)(5660300002)(2906002)(316002)(66476007)(6486002)(66946007)(6512007)(8936002)(69590400007)(186003)(6506007)(66556008)(16526019)(26005)(86362001)(1076003)(81156014); DIR:OUT; SFP:1102; Received-SPF: None (protection.outlook.com: virtuozzo.com does not designate permitted sender hosts) X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-Network-Message-Id: 3ec3f310-36f2-459f-b11a-08d7eab8cd4c X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Apr 2020 14:39:33.7721 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: aweXqm4nqMIOtj9JvRcs2VkvAWv3mWeDZP55MxGEJA0osL4L3CVQgeiGOyL+69a+NS/gWmkFENkPtEW19qpehxFmHb7/K/wXmh5HIU/NmEw= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM7PR08MB5336 Received-SPF: pass client-ip=40.107.4.124; envelope-from=vsementsov@virtuozzo.com; helo=EUR03-DB5-obe.outbound.protection.outlook.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/27 10:39:33 X-ACL-Warn: Detected OS = Windows NT kernel [generic] [fuzzy] X-Received-From: 40.107.4.124 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: kwolf@redhat.com, fam@euphon.net, vsementsov@virtuozzo.com, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We are going to use bdrv_co_pwritev_part and bdrv_co_preadv_part in bdrv_rw_co_entry, so move it down. Note: Comment formatting was changed to conform to coding style and function order was changed. Otherwise the code is unmodified. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Stefan Hajnoczi --- block/io.c | 361 +++++++++++++++++++++++++++-------------------------- 1 file changed, 181 insertions(+), 180 deletions(-) diff --git a/block/io.c b/block/io.c index 1134f8144a..061f3f2590 100644 --- a/block/io.c +++ b/block/io.c @@ -891,186 +891,6 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, return 0; } -typedef struct RwCo { - BdrvChild *child; - int64_t offset; - QEMUIOVector *qiov; - bool is_write; - int ret; - BdrvRequestFlags flags; -} RwCo; - -static void coroutine_fn bdrv_rw_co_entry(void *opaque) -{ - RwCo *rwco = opaque; - - if (!rwco->is_write) { - rwco->ret = bdrv_co_preadv(rwco->child, rwco->offset, - rwco->qiov->size, rwco->qiov, - rwco->flags); - } else { - rwco->ret = bdrv_co_pwritev(rwco->child, rwco->offset, - rwco->qiov->size, rwco->qiov, - rwco->flags); - } - aio_wait_kick(); -} - -/* - * Process a vectored synchronous request using coroutines - */ -static int bdrv_prwv_co(BdrvChild *child, int64_t offset, - QEMUIOVector *qiov, bool is_write, - BdrvRequestFlags flags) -{ - Coroutine *co; - RwCo rwco = { - .child = child, - .offset = offset, - .qiov = qiov, - .is_write = is_write, - .ret = NOT_DONE, - .flags = flags, - }; - - if (qemu_in_coroutine()) { - /* Fast-path if already in coroutine context */ - bdrv_rw_co_entry(&rwco); - } else { - co = qemu_coroutine_create(bdrv_rw_co_entry, &rwco); - bdrv_coroutine_enter(child->bs, co); - BDRV_POLL_WHILE(child->bs, rwco.ret == NOT_DONE); - } - return rwco.ret; -} - -int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, - int bytes, BdrvRequestFlags flags) -{ - QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes); - - return bdrv_prwv_co(child, offset, &qiov, true, - BDRV_REQ_ZERO_WRITE | flags); -} - -/* - * Completely zero out a block device with the help of bdrv_pwrite_zeroes. - * The operation is sped up by checking the block status and only writing - * zeroes to the device if they currently do not return zeroes. Optional - * flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP, - * BDRV_REQ_FUA). - * - * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). - */ -int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) -{ - int ret; - int64_t target_size, bytes, offset = 0; - BlockDriverState *bs = child->bs; - - target_size = bdrv_getlength(bs); - if (target_size < 0) { - return target_size; - } - - for (;;) { - bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES); - if (bytes <= 0) { - return 0; - } - ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL); - if (ret < 0) { - return ret; - } - if (ret & BDRV_BLOCK_ZERO) { - offset += bytes; - continue; - } - ret = bdrv_pwrite_zeroes(child, offset, bytes, flags); - if (ret < 0) { - return ret; - } - offset += bytes; - } -} - -int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov) -{ - int ret; - - ret = bdrv_prwv_co(child, offset, qiov, false, 0); - if (ret < 0) { - return ret; - } - - return qiov->size; -} - -/* See bdrv_pwrite() for the return codes */ -int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes) -{ - QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); - - if (bytes < 0) { - return -EINVAL; - } - - return bdrv_preadv(child, offset, &qiov); -} - -int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov) -{ - int ret; - - ret = bdrv_prwv_co(child, offset, qiov, true, 0); - if (ret < 0) { - return ret; - } - - return qiov->size; -} - -/* Return no. of bytes on success or < 0 on error. Important errors are: - -EIO generic I/O error (may happen for all errors) - -ENOMEDIUM No media inserted. - -EINVAL Invalid offset or number of bytes - -EACCES Trying to write a read-only device -*/ -int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes) -{ - QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); - - if (bytes < 0) { - return -EINVAL; - } - - return bdrv_pwritev(child, offset, &qiov); -} - -/* - * Writes to the file and ensures that no writes are reordered across this - * request (acts as a barrier) - * - * Returns 0 on success, -errno in error cases. - */ -int bdrv_pwrite_sync(BdrvChild *child, int64_t offset, - const void *buf, int count) -{ - int ret; - - ret = bdrv_pwrite(child, offset, buf, count); - if (ret < 0) { - return ret; - } - - ret = bdrv_flush(child->bs); - if (ret < 0) { - return ret; - } - - return 0; -} - typedef struct CoroutineIOCompletion { Coroutine *coroutine; int ret; @@ -2185,6 +2005,187 @@ int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset, BDRV_REQ_ZERO_WRITE | flags); } +typedef struct RwCo { + BdrvChild *child; + int64_t offset; + QEMUIOVector *qiov; + bool is_write; + int ret; + BdrvRequestFlags flags; +} RwCo; + +static void coroutine_fn bdrv_rw_co_entry(void *opaque) +{ + RwCo *rwco = opaque; + + if (!rwco->is_write) { + rwco->ret = bdrv_co_preadv(rwco->child, rwco->offset, + rwco->qiov->size, rwco->qiov, + rwco->flags); + } else { + rwco->ret = bdrv_co_pwritev(rwco->child, rwco->offset, + rwco->qiov->size, rwco->qiov, + rwco->flags); + } + aio_wait_kick(); +} + +/* + * Process a vectored synchronous request using coroutines + */ +static int bdrv_prwv_co(BdrvChild *child, int64_t offset, + QEMUIOVector *qiov, bool is_write, + BdrvRequestFlags flags) +{ + Coroutine *co; + RwCo rwco = { + .child = child, + .offset = offset, + .qiov = qiov, + .is_write = is_write, + .ret = NOT_DONE, + .flags = flags, + }; + + if (qemu_in_coroutine()) { + /* Fast-path if already in coroutine context */ + bdrv_rw_co_entry(&rwco); + } else { + co = qemu_coroutine_create(bdrv_rw_co_entry, &rwco); + bdrv_coroutine_enter(child->bs, co); + BDRV_POLL_WHILE(child->bs, rwco.ret == NOT_DONE); + } + return rwco.ret; +} + +int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, + int bytes, BdrvRequestFlags flags) +{ + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes); + + return bdrv_prwv_co(child, offset, &qiov, true, + BDRV_REQ_ZERO_WRITE | flags); +} + +/* See bdrv_pwrite() for the return codes */ +int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes) +{ + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); + + if (bytes < 0) { + return -EINVAL; + } + + return bdrv_preadv(child, offset, &qiov); +} + +int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov) +{ + int ret; + + ret = bdrv_prwv_co(child, offset, qiov, true, 0); + if (ret < 0) { + return ret; + } + + return qiov->size; +} + +/* + * Return no. of bytes on success or < 0 on error. Important errors are: + * -EIO generic I/O error (may happen for all errors) + * -ENOMEDIUM No media inserted. + * -EINVAL Invalid offset or number of bytes + * -EACCES Trying to write a read-only device + */ +int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes) +{ + QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); + + if (bytes < 0) { + return -EINVAL; + } + + return bdrv_pwritev(child, offset, &qiov); +} + +/* + * Writes to the file and ensures that no writes are reordered across this + * request (acts as a barrier) + * + * Returns 0 on success, -errno in error cases. + */ +int bdrv_pwrite_sync(BdrvChild *child, int64_t offset, + const void *buf, int count) +{ + int ret; + + ret = bdrv_pwrite(child, offset, buf, count); + if (ret < 0) { + return ret; + } + + ret = bdrv_flush(child->bs); + if (ret < 0) { + return ret; + } + + return 0; +} + +/* + * Completely zero out a block device with the help of bdrv_pwrite_zeroes. + * The operation is sped up by checking the block status and only writing + * zeroes to the device if they currently do not return zeroes. Optional + * flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP, + * BDRV_REQ_FUA). + * + * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). + */ +int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) +{ + int ret; + int64_t target_size, bytes, offset = 0; + BlockDriverState *bs = child->bs; + + target_size = bdrv_getlength(bs); + if (target_size < 0) { + return target_size; + } + + for (;;) { + bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES); + if (bytes <= 0) { + return 0; + } + ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL); + if (ret < 0) { + return ret; + } + if (ret & BDRV_BLOCK_ZERO) { + offset += bytes; + continue; + } + ret = bdrv_pwrite_zeroes(child, offset, bytes, flags); + if (ret < 0) { + return ret; + } + offset += bytes; + } +} + +int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov) +{ + int ret; + + ret = bdrv_prwv_co(child, offset, qiov, false, 0); + if (ret < 0) { + return ret; + } + + return qiov->size; +} + /* * Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not. */ -- 2.21.0