From patchwork Wed Nov 16 13:48:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 13045270 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 D45A3C4332F for ; Wed, 16 Nov 2022 14:02:25 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ovImv-0000jx-6f; Wed, 16 Nov 2022 08:49:13 -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 1ovImo-0000e5-GP for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:06 -0500 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 1ovImk-0007zb-2l for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668606537; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4YSqZKWu6ML3JWAFCUXYj1V3Azhvoz41m0uIXXFHM7E=; b=HffZGAcZL3guGBeSkZ0NM6lu/r5JJjsPzJWjG8fCCZqgjESbLRRG0IvXSe81BQXC8gWXCj 1FIFm2LLIAE8DjMRzhUVKr/AYhmlkSGyiS4mvqIgZ12WRB5rO5u6uqAs1dM4xsS1GzLI1C n9dsXPZYzDMDMtqdNdeOHyx4JnG25oE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-311-xSR2lpHGOCa-u0h8MXEfow-1; Wed, 16 Nov 2022 08:48:54 -0500 X-MC-Unique: xSR2lpHGOCa-u0h8MXEfow-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 420D11C09B6F; Wed, 16 Nov 2022 13:48:54 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id E91F44A9254; Wed, 16 Nov 2022 13:48:53 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Cc: Kevin Wolf , Hanna Reitz , John Snow , Paolo Bonzini , Vladimir Sementsov-Ogievskiy , Stefan Hajnoczi , Fam Zheng , Eric Blake , Cleber Rosa , qemu-devel@nongnu.org, Emanuele Giuseppe Esposito Subject: [PATCH 06/20] block: assert that graph read and writes are performed correctly Date: Wed, 16 Nov 2022 08:48:36 -0500 Message-Id: <20221116134850.3051419-7-eesposit@redhat.com> In-Reply-To: <20221116134850.3051419-1-eesposit@redhat.com> References: <20221116134850.3051419-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eesposit@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_H2=-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 Remove the old assert_bdrv_graph_writable, and replace it with the new version using graph-lock API. See the function documentation for more information. Signed-off-by: Emanuele Giuseppe Esposito --- block.c | 4 ++-- block/graph-lock.c | 11 +++++++++++ include/block/block_int-global-state.h | 17 ----------------- include/block/graph-lock.h | 15 +++++++++++++++ 4 files changed, 28 insertions(+), 19 deletions(-) diff --git a/block.c b/block.c index afab74d4da..1c870d85e6 100644 --- a/block.c +++ b/block.c @@ -1414,7 +1414,7 @@ static void bdrv_child_cb_attach(BdrvChild *child) { BlockDriverState *bs = child->opaque; - assert_bdrv_graph_writable(bs); + assert_bdrv_graph_writable(); QLIST_INSERT_HEAD(&bs->children, child, next); if (bs->drv->is_filter || (child->role & BDRV_CHILD_FILTERED)) { @@ -1461,7 +1461,7 @@ static void bdrv_child_cb_detach(BdrvChild *child) bdrv_backing_detach(child); } - assert_bdrv_graph_writable(bs); + assert_bdrv_graph_writable(); QLIST_REMOVE(child, next); if (child == bs->backing) { assert(child != bs->file); diff --git a/block/graph-lock.c b/block/graph-lock.c index c3c6eeedad..07476fd7c8 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -242,3 +242,14 @@ void coroutine_fn bdrv_graph_co_rdunlock(void) aio_wait_kick(); } } + +void assert_bdrv_graph_readable(void) +{ + assert(qemu_in_main_thread() || reader_count()); +} + +void assert_bdrv_graph_writable(void) +{ + assert(qemu_in_main_thread()); + assert(qatomic_read(&has_writer)); +} diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h index b49f4eb35b..2f0993f6e9 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -310,21 +310,4 @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs, */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); -/** - * Make sure that the function is running under both drain and BQL. - * The latter protects from concurrent writings - * from the GS API, while the former prevents concurrent reads - * from I/O. - */ -static inline void assert_bdrv_graph_writable(BlockDriverState *bs) -{ - /* - * TODO: this function is incomplete. Because the users of this - * assert lack the necessary drains, check only for BQL. - * Once the necessary drains are added, - * assert also for qatomic_read(&bs->quiesce_counter) > 0 - */ - assert(qemu_in_main_thread()); -} - #endif /* BLOCK_INT_GLOBAL_STATE_H */ diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index fc806aefa3..9430707dca 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -126,5 +126,20 @@ void coroutine_fn bdrv_graph_co_rdlock(void); */ void coroutine_fn bdrv_graph_co_rdunlock(void); +/* + * assert_bdrv_graph_readable: + * Make sure that the reader is either the main loop, + * or there is at least a reader helding the rdlock. + * In this way an incoming writer is aware of the read and waits. + */ +void assert_bdrv_graph_readable(void); + +/* + * assert_bdrv_graph_writable: + * Make sure that the writer is the main loop and has set @has_writer, + * so that incoming readers will pause. + */ +void assert_bdrv_graph_writable(void); + #endif /* GRAPH_LOCK_H */