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bh=o29XndGUfRwY0P3peJ9TK4DE+Rh+I26/FbueKykjyy8=; b=HhT6Oxk/nyKJYmhTnTfx/FJbZtMthkHZ2HhC3ALM8UzwkVYLoQ+FDbm8VZI/Dmj18tUH5m +CMiNINyf4pfOkQG2AqWQgQF6kcvm8HvJ8pk1REsS+RWivSEOcezDvPFePDZ4j7oJ2ZYPL vdTY8fCu+Bcdryms/EUDwQUrb3GPGR8= X-MC-Unique: d7yA4pt3PviZvUvUeGGipw-1 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 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: -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+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. 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-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..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" =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 +66,27 @@ 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) +{ + bool res; + QEMU_LOCK_GUARD(&s->lock); + res =3D co_try_get_from_shres_locked(s, n); + + return res; +} + 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 2.30.2