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Wed, 11 Mar 2020 12:38:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583930301; 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=5nh15vDTrDF7YqOGEJcfqFZtZYBVL088KNsl1qKAeQ4=; b=bJL0lfY6yifpawgh5yi7+GA59vHztvvFv5iJDjkjQptLyKu4FwnlOjmeYokE3XcGVJjDZM ZsDTSv/3GAI08fAMLPkkvIKHC7Ms+bE+FIa5mNRO9uxRrlrUVWGWLrpBkLAcUT3XiPT0v0 /2dBGHk3draql8zXaPpjsGiJmgxBEeg= X-MC-Unique: 8cb4jjRxM2y74-WD7T16kA-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 1/2] thread: add QemuRecMutex lock guards Date: Wed, 11 Mar 2020 12:36:23 +0000 Message-Id: <20200311123624.277221-2-stefanha@redhat.com> In-Reply-To: <20200311123624.277221-1-stefanha@redhat.com> References: <20200311123624.277221-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: Paolo Bonzini , =?UTF-8?q?Alex=20Benn=C3=A9e?= , "Dr. David Alan Gilbert" , Stefan Hajnoczi 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" This patch introduces two lock guard macros that automatically unlock a QemuRecMutex: void f(void) { QEMU_REC_MUTEX_LOCK_GUARD(&mutex); if (!may_fail()) { return; /* automatically unlocks mutex */ } ... } and: WITH_QEMU_REC_MUTEX_LOCK_GUARD(&mutex) { if (!may_fail()) { return; /* automatically unlocks mutex */ } } /* automatically unlocks mutex here */ ... Convert TCG plugins functions that benefit from these macros. Manual qemu_rec_mutex_lock/unlock() callers are left unmodified in cases where clarity would not improve by switching to the macros. Signed-off-by: Stefan Hajnoczi --- include/qemu/thread.h | 26 ++++++++++++++++++++++++++ plugins/core.c | 6 ++---- plugins/loader.c | 15 +++++++-------- 3 files changed, 35 insertions(+), 12 deletions(-) diff --git a/include/qemu/thread.h b/include/qemu/thread.h index 047db0307e..3993ab7b25 100644 --- a/include/qemu/thread.h +++ b/include/qemu/thread.h @@ -132,6 +132,32 @@ static inline int (qemu_rec_mutex_trylock)(QemuRecMute= x *mutex) /* Prototypes for other functions are in thread-posix.h/thread-win32.h. */ void qemu_rec_mutex_init(QemuRecMutex *mutex); =20 +static inline QemuRecMutex *qemu_rec_mutex_auto_lock(QemuRecMutex *mutex) +{ + qemu_rec_mutex_lock(mutex); + return mutex; +} + +static inline void qemu_rec_mutex_auto_unlock(QemuRecMutex *mutex) +{ + if (mutex) { + qemu_rec_mutex_unlock(mutex); + } +} + +G_DEFINE_AUTOPTR_CLEANUP_FUNC(QemuRecMutex, qemu_rec_mutex_auto_unlock) + +#define WITH_QEMU_REC_MUTEX_LOCK_GUARD_(mutex, var) \ + for (g_autoptr(QemuRecMutex) var =3D qemu_rec_mutex_auto_lock((mutex))= ; \ + var; qemu_rec_mutex_auto_unlock(var), var =3D NULL) + +#define WITH_QEMU_REC_MUTEX_LOCK_GUARD(mutex) \ + WITH_QEMU_REC_MUTEX_LOCK_GUARD_((mutex), qemu_rec_mutex_auto##__COUNTE= R__) + +#define QEMU_REC_MUTEX_LOCK_GUARD(mutex) \ + g_autoptr(QemuRecMutex) qemu_rec_mutex_auto##__COUNTER__ =3D \ + qemu_rec_mutex_auto_lock((mutex)) + void qemu_cond_init(QemuCond *cond); void qemu_cond_destroy(QemuCond *cond); =20 diff --git a/plugins/core.c b/plugins/core.c index ed863011ba..cf8c85de9c 100644 --- a/plugins/core.c +++ b/plugins/core.c @@ -150,11 +150,11 @@ do_plugin_register_cb(qemu_plugin_id_t id, enum qemu_= plugin_event ev, { struct qemu_plugin_ctx *ctx; =20 - qemu_rec_mutex_lock(&plugin.lock); + QEMU_REC_MUTEX_LOCK_GUARD(&plugin.lock); ctx =3D plugin_id_to_ctx_locked(id); /* if the plugin is on its way out, ignore this request */ if (unlikely(ctx->uninstalling)) { - goto out_unlock; + return; } if (func) { struct qemu_plugin_cb *cb =3D ctx->callbacks[ev]; @@ -178,8 +178,6 @@ do_plugin_register_cb(qemu_plugin_id_t id, enum qemu_pl= ugin_event ev, } else { plugin_unregister_cb__locked(ctx, ev); } - out_unlock: - qemu_rec_mutex_unlock(&plugin.lock); } =20 void plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev, diff --git a/plugins/loader.c b/plugins/loader.c index 15fc7e5515..9742c8d41d 100644 --- a/plugins/loader.c +++ b/plugins/loader.c @@ -367,15 +367,14 @@ void plugin_reset_uninstall(qemu_plugin_id_t id, struct qemu_plugin_reset_data *data; struct qemu_plugin_ctx *ctx; =20 - qemu_rec_mutex_lock(&plugin.lock); - ctx =3D plugin_id_to_ctx_locked(id); - if (ctx->uninstalling || (reset && ctx->resetting)) { - qemu_rec_mutex_unlock(&plugin.lock); - return; + WITH_QEMU_REC_MUTEX_LOCK_GUARD(&plugin.lock) { + ctx =3D plugin_id_to_ctx_locked(id); + if (ctx->uninstalling || (reset && ctx->resetting)) { + return; + } + ctx->resetting =3D reset; + ctx->uninstalling =3D !reset; } - ctx->resetting =3D reset; - ctx->uninstalling =3D !reset; - qemu_rec_mutex_unlock(&plugin.lock); =20 data =3D g_new(struct qemu_plugin_reset_data, 1); data->ctx =3D ctx; --=20 2.24.1