From patchwork Tue May 18 09:40:58 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: 1480158 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=HhT6Oxk/; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4FkrtQ2cYwz9sW5 for ; Tue, 18 May 2021 19:53:50 +1000 (AEST) Received: from localhost ([::1]:54986 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1liwQ8-0007JZ-8y for incoming@patchwork.ozlabs.org; Tue, 18 May 2021 05:53:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35834) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1liwE9-0002x8-Tx for qemu-devel@nongnu.org; Tue, 18 May 2021 05:41:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:55884) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1liwE8-000846-4k for qemu-devel@nongnu.org; Tue, 18 May 2021 05:41:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621330883; 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=o29XndGUfRwY0P3peJ9TK4DE+Rh+I26/FbueKykjyy8=; b=HhT6Oxk/nyKJYmhTnTfx/FJbZtMthkHZ2HhC3ALM8UzwkVYLoQ+FDbm8VZI/Dmj18tUH5m +CMiNINyf4pfOkQG2AqWQgQF6kcvm8HvJ8pk1REsS+RWivSEOcezDvPFePDZ4j7oJ2ZYPL vdTY8fCu+Bcdryms/EUDwQUrb3GPGR8= 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-497-d7yA4pt3PviZvUvUeGGipw-1; Tue, 18 May 2021 05:41:21 -0400 X-MC-Unique: d7yA4pt3PviZvUvUeGGipw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BC138101371E; Tue, 18 May 2021 09:41:20 +0000 (UTC) Received: from localhost.localdomain (ovpn-114-236.ams2.redhat.com [10.36.114.236]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3F7742ED6F; Tue, 18 May 2021 09:41:18 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [PATCH v2 5/5] co-shared-resource: protect with a mutex Date: Tue, 18 May 2021 11:40:58 +0200 Message-Id: <20210518094058.25952-6-eesposit@redhat.com> In-Reply-To: <20210518094058.25952-1-eesposit@redhat.com> References: <20210518094058.25952-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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=216.205.24.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.374, 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_H4=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Emanuele Giuseppe Esposito , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , Paolo Bonzini , John Snow Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" co-shared-resource is currently not thread-safe, as also reported in co-shared-resource.h. Add a QemuMutex because co_try_get_from_shres can also be invoked from non-coroutine context. Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Vladimir Sementsov-Ogievskiy --- include/qemu/co-shared-resource.h | 4 +--- util/qemu-co-shared-resource.c | 27 ++++++++++++++++++++++----- 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/include/qemu/co-shared-resource.h b/include/qemu/co-shared-resource.h index 4e4503004c..78ca5850f8 100644 --- a/include/qemu/co-shared-resource.h +++ b/include/qemu/co-shared-resource.h @@ -26,15 +26,13 @@ #ifndef QEMU_CO_SHARED_RESOURCE_H #define QEMU_CO_SHARED_RESOURCE_H - +/* Accesses to co-shared-resource API are thread-safe */ typedef struct SharedResource SharedResource; /* * Create SharedResource structure * * @total: total amount of some resource to be shared between clients - * - * Note: this API is not thread-safe. */ SharedResource *shres_create(uint64_t total); diff --git a/util/qemu-co-shared-resource.c b/util/qemu-co-shared-resource.c index 1c83cd9d29..bb875a86be 100644 --- a/util/qemu-co-shared-resource.c +++ b/util/qemu-co-shared-resource.c @@ -28,10 +28,13 @@ #include "qemu/co-shared-resource.h" struct SharedResource { - uint64_t total; - uint64_t available; + uint64_t total; /* Set in shres_create() and not changed anymore */ + /* State fields protected by lock */ + uint64_t available; CoQueue queue; + + QemuMutex lock; }; SharedResource *shres_create(uint64_t total) @@ -40,6 +43,7 @@ SharedResource *shres_create(uint64_t total) s->total = s->available = total; qemu_co_queue_init(&s->queue); + qemu_mutex_init(&s->lock); return s; } @@ -47,10 +51,12 @@ SharedResource *shres_create(uint64_t total) void shres_destroy(SharedResource *s) { assert(s->available == s->total); + qemu_mutex_destroy(&s->lock); g_free(s); } -bool co_try_get_from_shres(SharedResource *s, uint64_t n) +/* Called with lock held. */ +static bool co_try_get_from_shres_locked(SharedResource *s, uint64_t n) { if (s->available >= n) { s->available -= n; @@ -60,16 +66,27 @@ bool co_try_get_from_shres(SharedResource *s, uint64_t n) return false; } +bool co_try_get_from_shres(SharedResource *s, uint64_t n) +{ + bool res; + QEMU_LOCK_GUARD(&s->lock); + res = co_try_get_from_shres_locked(s, n); + + return res; +} + void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n) { assert(n <= s->total); - while (!co_try_get_from_shres(s, n)) { - qemu_co_queue_wait(&s->queue, NULL); + QEMU_LOCK_GUARD(&s->lock); + while (!co_try_get_from_shres_locked(s, n)) { + qemu_co_queue_wait(&s->queue, &s->lock); } } void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n) { + QEMU_LOCK_GUARD(&s->lock); assert(s->total - s->available >= n); s->available += n; qemu_co_queue_restart_all(&s->queue);