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 2A855C7EE30 for ; Tue, 1 Jul 2025 11:38:40 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uWZIw-0003gZ-BJ; Tue, 01 Jul 2025 07:37:38 -0400 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 1uWZIr-0003g8-00 for qemu-devel@nongnu.org; Tue, 01 Jul 2025 07:37:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uWZIn-00024U-6t for qemu-devel@nongnu.org; Tue, 01 Jul 2025 07:37:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1751369845; 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: in-reply-to:in-reply-to:references:references; bh=vw5O4lMVxeF8wcY5LvDDfJqxCwiPzAWKcuF+9FH0pxE=; b=h4t5bfobRHdVqEaPTmiAZM+FKyvnFIKmPyjgs4wTKLqlZeEcIYYkrCk6sw1iS0MESmg0BX 5DmrKFlXtjbsokOJm9nOdynce9nLONrmcDhEZrVmFkoBCmjIcVXw7Hu2wkgZa75msZQ69y Hd+0vNThJRXcu1ur5/kFtNaqwNP7j3I= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-153-6UyDl35rNMmEEnclqVAofg-1; Tue, 01 Jul 2025 07:37:22 -0400 X-MC-Unique: 6UyDl35rNMmEEnclqVAofg-1 X-Mimecast-MFC-AGG-ID: 6UyDl35rNMmEEnclqVAofg_1751369840 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8F87B1808984; Tue, 1 Jul 2025 11:37:19 +0000 (UTC) Received: from redhat.com (unknown [10.44.34.118]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id ABA2730001B1; Tue, 1 Jul 2025 11:37:13 +0000 (UTC) Date: Tue, 1 Jul 2025 13:37:10 +0200 From: Kevin Wolf To: Fiona Ebner Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, den@virtuozzo.com, andrey.drobyshev@virtuozzo.com, hreitz@redhat.com, stefanha@redhat.com, eblake@redhat.com, jsnow@redhat.com, vsementsov@yandex-team.ru, xiechanglong.d@gmail.com, wencongyang2@huawei.com, berto@igalia.com, fam@euphon.net, ari@tuxera.com Subject: Re: [PATCH v4 24/48] block: add bdrv_graph_wrlock_drained() convenience wrapper Message-ID: References: <20250530151125.955508-1-f.ebner@proxmox.com> <20250530151125.955508-25-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250530151125.955508-25-f.ebner@proxmox.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: 2.1.29 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 Am 30.05.2025 um 17:11 hat Fiona Ebner geschrieben: > Many write-locked sections are also drained sections. A new > bdrv_graph_wrunlock_drained() wrapper around bdrv_graph_wrunlock() is > introduced, which will begin a drained section first. A global > variable is used so bdrv_graph_wrunlock() knows if it also needs > to end such a drained section. Both the aio_poll call in > bdrv_graph_wrlock() and the aio_bh_poll() in bdrv_graph_wrunlock() > can re-enter a write-locked section. While for the latter, ending the > drain could be moved to before the call, the former requires that the > variable is a counter and not just a boolean. > > Since the wrapper calls bdrv_drain_all_begin(), which must be called > with the graph unlocked, mark the wrapper as GRAPH_UNLOCKED too. > > The switch to the new helpers was generated with the following > commands and then manually checked: > find . -name '*.c' -exec sed -i -z 's/bdrv_drain_all_begin();\n\s*bdrv_graph_wrlock();/bdrv_graph_wrlock_drained();/g' {} ';' > find . -name '*.c' -exec sed -i -z 's/bdrv_graph_wrunlock();\n\s*bdrv_drain_all_end();/bdrv_graph_wrunlock();/g' {} ';' > > Suggested-by: Kevin Wolf > Signed-off-by: Fiona Ebner > --- > > Changes in v4: > * Adapt to context changes from earlier patch. > * Mark the wrapper as GRAPH_UNLOCKED itself > diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h > index 2c26c72108..b564cba2c0 100644 > --- a/include/block/graph-lock.h > +++ b/include/block/graph-lock.h > @@ -112,10 +112,21 @@ void unregister_aiocontext(AioContext *ctx); > void no_coroutine_fn TSA_ACQUIRE(graph_lock) TSA_NO_TSA > bdrv_graph_wrlock(void); > > +/* > + * bdrv_graph_wrlock_drained: > + * Similar to bdrv_graph_wrlock, but will begin a drained section before > + * locking. > + */ > +void no_coroutine_fn TSA_ACQUIRE(graph_lock) TSA_NO_TSA GRAPH_UNLOCKED > +bdrv_graph_wrlock_drained(void); GRAPH_UNLOCKED is redundant. TSA_ACQUIRE(graph_lock) already means that you can't call the function while holding the lock. Kevin