From patchwork Tue Oct 5 14:31:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 12536957 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6189C433FE for ; Tue, 5 Oct 2021 14:54:15 +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 49B1461354 for ; Tue, 5 Oct 2021 14:54:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 49B1461354 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:60660 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXlpe-0004rX-F6 for qemu-devel@archiver.kernel.org; Tue, 05 Oct 2021 10:54:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53366) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXlX9-0003Iq-8C for qemu-devel@nongnu.org; Tue, 05 Oct 2021 10:35:07 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:28768) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXlX1-0004gt-Ry for qemu-devel@nongnu.org; Tue, 05 Oct 2021 10:35:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633444499; 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=VXQ0943rYVNPxRJFPwjFcqM+GaHXm++hO9CmecVP9zk=; b=IF/izj+UUrGgC3bHmroH6s4rbpJpp//0PJgVlwnwF609W0o+pCFYPa25p1Zq89jIgMvjj1 Mc+5qiwzKBg1clHXntUggUdnIG5h94SzT91+4tI4C5cvxrFIGL/lzS3TqlkcyBytLFRt5t s/IhNicOXIDVMUP2j9ypprqkdNg+wSQ= 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-36-UvRbiH0IOie4qAzFim_Y2g-1; Tue, 05 Oct 2021 10:34:58 -0400 X-MC-Unique: UvRbiH0IOie4qAzFim_Y2g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1ED462E7A; Tue, 5 Oct 2021 14:34:57 +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 E40701002391; Tue, 5 Oct 2021 14:34:55 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [RFC PATCH v2 09/25] include/block/blockjob_int.h: split header into I/O and GS API Date: Tue, 5 Oct 2021 10:31:59 -0400 Message-Id: <20211005143215.29500-10-eesposit@redhat.com> In-Reply-To: <20211005143215.29500-1-eesposit@redhat.com> References: <20211005143215.29500-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, 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_H2=-0.001, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , Vladimir Sementsov-Ogievskiy , =?utf-8?q?Daniel_P?= =?utf-8?q?=2E_Berrang=C3=A9?= , Eduardo Habkost , Juan Quintela , qemu-devel@nongnu.org, John Snow , Emanuele Giuseppe Esposito , Richard Henderson , Markus Armbruster , "Dr. David Alan Gilbert" , Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Since the I/O functions are not many, keep a single file. Also split the function pointers in BlockJobDriver. Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Stefan Hajnoczi --- include/block/blockjob_int.h | 55 ++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h index 6633d83da2..bac4e8f46d 100644 --- a/include/block/blockjob_int.h +++ b/include/block/blockjob_int.h @@ -38,6 +38,12 @@ struct BlockJobDriver { /** Generic JobDriver callbacks and settings */ JobDriver job_driver; + /* + * I/O API functions. These functions are thread-safe, and therefore + * can run in any thread as long as they have called + * aio_context_acquire/release(). + */ + /* * Returns whether the job has pending requests for the child or will * submit new requests before the next pause point. This callback is polled @@ -46,6 +52,28 @@ struct BlockJobDriver { */ bool (*drained_poll)(BlockJob *job); + /* + * Global state (GS) API. These functions run under the BQL lock. + * + * If a function modifies the graph, it also uses drain and/or + * aio_context_acquire/release to be sure it has unique access. + * aio_context locking is needed together with BQL because of + * the thread-safe I/O API that concurrently runs and accesses + * the graph without the BQL. + * + * It is important to note that not all of these functions are + * necessarily limited to running under the BQL, but they would + * require additional auditing and may small thread-safety changes + * to move them into the I/O API. Often it's not worth doing that + * work since the APIs are only used with the BQL held at the + * moment, so they have been placed in the GS API (for now). + * + * All callers that use these function pointers must + * use this assertion: + * g_assert(qemu_in_main_thread()); + * to catch when they are accidentally called without the BQL. + */ + /* * If the callback is not NULL, it will be invoked before the job is * resumed in a new AioContext. This is the place to move any resources @@ -56,6 +84,27 @@ struct BlockJobDriver { void (*set_speed)(BlockJob *job, int64_t speed); }; +/* + * Global state (GS) API. These functions run under the BQL lock. + * + * If a function modifies the graph, it also uses drain and/or + * aio_context_acquire/release to be sure it has unique access. + * aio_context locking is needed together with BQL because of + * the thread-safe I/O API that concurrently runs and accesses + * the graph without the BQL. + * + * It is important to note that not all of these functions are + * necessarily limited to running under the BQL, but they would + * require additional auditing and may small thread-safety changes + * to move them into the I/O API. Often it's not worth doing that + * work since the APIs are only used with the BQL held at the + * moment, so they have been placed in the GS API (for now). + * + * All functions below must use this assertion: + * g_assert(qemu_in_main_thread()); + * to catch when they are accidentally called without the BQL. + */ + /** * block_job_create: * @job_id: The id of the newly-created job, or %NULL to have one @@ -98,6 +147,12 @@ void block_job_free(Job *job); */ void block_job_user_resume(Job *job); +/* + * I/O API functions. These functions are thread-safe, and therefore + * can run in any thread as long as they have called + * aio_context_acquire/release(). + */ + /** * block_job_ratelimit_get_delay: *