From nobody Mon Feb 9 07:56:35 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1623658573324186.64772066410728; Mon, 14 Jun 2021 01:16:13 -0700 (PDT) Received: from localhost ([::1]:43244 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lshlU-0008EN-2o for importer@patchew.org; Mon, 14 Jun 2021 04:16:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40950) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lshhZ-0002Rv-R0 for qemu-devel@nongnu.org; Mon, 14 Jun 2021 04:12:09 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25752) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lshhW-0000hV-M7 for qemu-devel@nongnu.org; Mon, 14 Jun 2021 04:12:09 -0400 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-209-Beyg8RgYMpyTCj_iryJdLQ-1; Mon, 14 Jun 2021 04:12:03 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C0DF08B78A8; Mon, 14 Jun 2021 08:12:02 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-49.ams2.redhat.com [10.36.113.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id 919985D6A8; Mon, 14 Jun 2021 08:11:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623658325; 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=rcjc6r/f+mn3kfy0n6RxXUHxQBUJj4DkTyKgaGZzToQ=; b=cd8hynZjY/jJ6WCR2Keh+gYf56wXsTmbzIdtwAGYoqnXctsA652HWnF6I38Dl3skr/Jvyg pgB+RcrsZcn/Yspi4bjJOtVd9saMsMg5zAMVXC32HsuWNmj1cFLykFVbx9npOY+UXRdzGz jYTEGTQSp5NDtjgTPvRFim6UwV28Ojc= X-MC-Unique: Beyg8RgYMpyTCj_iryJdLQ-1 From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [PATCH v3 5/5] co-shared-resource: protect with a mutex Date: Mon, 14 Jun 2021 10:11:30 +0200 Message-Id: <20210614081130.22134-6-eesposit@redhat.com> In-Reply-To: <20210614081130.22134-1-eesposit@redhat.com> References: <20210614081130.22134-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.199, 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=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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. Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Emanuele Giuseppe Esposito --- include/qemu/co-shared-resource.h | 4 +--- util/qemu-co-shared-resource.c | 24 +++++++++++++++++++----- 2 files changed, 20 insertions(+), 8 deletions(-) diff --git a/include/qemu/co-shared-resource.h b/include/qemu/co-shared-res= ource.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 =20 - +/* Accesses to co-shared-resource API are thread-safe */ typedef struct SharedResource SharedResource; =20 /* * 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); =20 diff --git a/util/qemu-co-shared-resource.c b/util/qemu-co-shared-resource.c index 1c83cd9d29..a66cc07e75 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" =20 struct SharedResource { - uint64_t total; - uint64_t available; + uint64_t total; /* Set in shres_create() and not changed anymore */ =20 + /* State fields protected by lock */ + uint64_t available; CoQueue queue; + + QemuMutex lock; }; =20 SharedResource *shres_create(uint64_t total) @@ -40,6 +43,7 @@ SharedResource *shres_create(uint64_t total) =20 s->total =3D s->available =3D total; qemu_co_queue_init(&s->queue); + qemu_mutex_init(&s->lock); =20 return s; } @@ -47,10 +51,12 @@ SharedResource *shres_create(uint64_t total) void shres_destroy(SharedResource *s) { assert(s->available =3D=3D s->total); + qemu_mutex_destroy(&s->lock); g_free(s); } =20 -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 >=3D n) { s->available -=3D n; @@ -60,16 +66,24 @@ bool co_try_get_from_shres(SharedResource *s, uint64_t = n) return false; } =20 +bool co_try_get_from_shres(SharedResource *s, uint64_t n) +{ + QEMU_LOCK_GUARD(&s->lock); + return co_try_get_from_shres_locked(s, n); +} + void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n) { assert(n <=3D 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); } } =20 void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n) { + QEMU_LOCK_GUARD(&s->lock); assert(s->total - s->available >=3D n); s->available +=3D n; qemu_co_queue_restart_all(&s->queue); --=20 2.31.1