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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E8B3CCEE342 for ; Tue, 18 Nov 2025 17:10:15 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vLP6x-00005b-6h; Tue, 18 Nov 2025 12:03:23 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vLP6u-0008Ut-Vs for qemu-devel@nongnu.org; Tue, 18 Nov 2025 12:03:21 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vLP6t-0004j7-Aw for qemu-devel@nongnu.org; Tue, 18 Nov 2025 12:03:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763485398; 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=BoVAI3DNADf87T1Nn/o5IlvAFQmrRR/j4uz+LlarMK8=; b=FejO6JO9E4Wt5X1X1ewXnANxGPkFIKQwpazMYbTXGQ8ABQ5I9tS7YDGJyhgkMt9rAfZxed P0eNidK1lTKMDIp1jfL/mevrQsxM4JRRO9f7aDuoQqp6NINIMZ/VgAWZf+9jVlctkGJc/K jrlP5Cc/5ZTjGcvr4yTgMgt/R8EMo40= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-594-U1WFyAmUNKWCCISDpaKiSg-1; Tue, 18 Nov 2025 12:03:14 -0500 X-MC-Unique: U1WFyAmUNKWCCISDpaKiSg-1 X-Mimecast-MFC-AGG-ID: U1WFyAmUNKWCCISDpaKiSg_1763485393 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8B295191B4C1; Tue, 18 Nov 2025 17:03:13 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.44.32.26]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 01CC8300A88D; Tue, 18 Nov 2025 17:03:11 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, richard.henderson@linaro.org, qemu-devel@nongnu.org Subject: [PULL 04/19] =?UTF-8?q?nfs:=20Run=20co=20BH=20CB=20in=20the=20cor?= =?UTF-8?q?outine=E2=80=99s=20AioContext?= Date: Tue, 18 Nov 2025 18:02:41 +0100 Message-ID: <20251118170256.272087-5-kwolf@redhat.com> In-Reply-To: <20251118170256.272087-1-kwolf@redhat.com> References: <20251118170256.272087-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Hanna Czenczek Like in “rbd: Run co BH CB in the coroutine’s AioContext”, drop the completion flag, yield exactly once, and run the BH in the coroutine’s AioContext. (Can be reproduced with multiqueue by adding a usleep(100000) before the `while (!task.complete)` loops.) Like in “iscsi: Run co BH CB in the coroutine’s AioContext”, this makes nfs_co_generic_bh_cb() trivial, so we can drop it in favor of just calling aio_co_wake() directly. Cc: qemu-stable@nongnu.org Signed-off-by: Hanna Czenczek Message-ID: <20251110154854.151484-5-hreitz@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/nfs.c | 41 ++++++++++++++++------------------------- 1 file changed, 16 insertions(+), 25 deletions(-) diff --git a/block/nfs.c b/block/nfs.c index 0a7d38db09..1d3a34a30c 100644 --- a/block/nfs.c +++ b/block/nfs.c @@ -69,7 +69,6 @@ typedef struct NFSClient { typedef struct NFSRPC { BlockDriverState *bs; int ret; - int complete; QEMUIOVector *iov; struct stat *st; Coroutine *co; @@ -230,14 +229,6 @@ static void coroutine_fn nfs_co_init_task(BlockDriverState *bs, NFSRPC *task) }; } -static void nfs_co_generic_bh_cb(void *opaque) -{ - NFSRPC *task = opaque; - - task->complete = 1; - aio_co_wake(task->co); -} - /* Called (via nfs_service) with QemuMutex held. */ static void nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data, @@ -256,8 +247,16 @@ nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data, if (task->ret < 0) { error_report("NFS Error: %s", nfs_get_error(nfs)); } - replay_bh_schedule_oneshot_event(task->client->aio_context, - nfs_co_generic_bh_cb, task); + + /* + * Safe to call: nfs_service(), which called us, is only run from the FD + * handlers, never from the request coroutine. The request coroutine in + * turn will yield unconditionally. + * No need to release the lock, even if we directly enter the coroutine, as + * the lock is never re-taken after yielding. (Note: If we do enter the + * coroutine, @task will probably be dangling once aio_co_wake() returns.) + */ + aio_co_wake(task->co); } static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, int64_t offset, @@ -278,9 +277,7 @@ static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, int64_t offset, nfs_set_events(client); } - while (!task.complete) { - qemu_coroutine_yield(); - } + qemu_coroutine_yield(); if (task.ret < 0) { return task.ret; @@ -328,9 +325,7 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, int64_t offset, nfs_set_events(client); } - while (!task.complete) { - qemu_coroutine_yield(); - } + qemu_coroutine_yield(); if (my_buffer) { g_free(buf); @@ -358,9 +353,7 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs) nfs_set_events(client); } - while (!task.complete) { - qemu_coroutine_yield(); - } + qemu_coroutine_yield(); return task.ret; } @@ -723,8 +716,8 @@ nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data, if (task->ret < 0) { error_report("NFS Error: %s", nfs_get_error(nfs)); } - replay_bh_schedule_oneshot_event(task->client->aio_context, - nfs_co_generic_bh_cb, task); + /* Safe to call, see nfs_co_generic_cb() */ + aio_co_wake(task->co); } static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs) @@ -748,9 +741,7 @@ static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs) nfs_set_events(client); } - while (!task.complete) { - qemu_coroutine_yield(); - } + qemu_coroutine_yield(); return (task.ret < 0 ? task.ret : st.st_blocks * 512); } -- 2.51.1