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Sun, 24 Apr 2016 14:10:30 -0700 (PDT) Received: from localhost.localdomain ([46.249.74.23]) by smtp.gmail.com with ESMTPSA id b2sm15440182wmb.9.2016.04.24.14.10.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 24 Apr 2016 14:10:30 -0700 (PDT) From: Ivaylo Dimitrov To: sakari.ailus@iki.fi Cc: sre@kernel.org, pali.rohar@gmail.com, pavel@ucw.cz, linux-media@vger.kernel.org Subject: [RFC PATCH 18/24] v4l2-async: per notifier locking Date: Mon, 25 Apr 2016 00:08:18 +0300 Message-Id: <1461532104-24032-19-git-send-email-ivo.g.dimitrov.75@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1461532104-24032-1-git-send-email-ivo.g.dimitrov.75@gmail.com> References: <20160420081427.GZ32125@valkosipuli.retiisi.org.uk> <1461532104-24032-1-git-send-email-ivo.g.dimitrov.75@gmail.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Spam-Status: No, score=-7.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Sebastian Reichel --- drivers/media/v4l2-core/v4l2-async.c | 50 ++++++++++++++++++------------------ include/media/v4l2-async.h | 2 ++ 2 files changed, 27 insertions(+), 25 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c index a4b224d..27789cd 100644 --- a/drivers/media/v4l2-core/v4l2-async.c +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -56,7 +56,6 @@ static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd) static LIST_HEAD(subdev_list); static LIST_HEAD(notifier_list); -static DEFINE_MUTEX(list_lock); static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd) @@ -106,14 +105,17 @@ static int v4l2_async_test_notify(struct v4l2_async_notifier *notifier, if (notifier->bound) { ret = notifier->bound(notifier, sd, asd); - if (ret < 0) + if (ret < 0) { + dev_warn(notifier->v4l2_dev->dev, "subdev bound failed\n"); return ret; + } } /* Move from the global subdevice list to notifier's done */ list_move(&sd->async_list, ¬ifier->done); ret = v4l2_device_register_subdev(notifier->v4l2_dev, sd); if (ret < 0) { + dev_warn(notifier->v4l2_dev->dev, "subdev register failed\n"); if (notifier->unbind) notifier->unbind(notifier, sd, asd); return ret; @@ -146,7 +148,7 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, { struct v4l2_subdev *sd, *tmp; struct v4l2_async_subdev *asd; - int i; + int ret = 0, i; if (!notifier->num_subdevs || notifier->num_subdevs > V4L2_MAX_SUBDEVS) return -EINVAL; @@ -154,6 +156,7 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, notifier->v4l2_dev = v4l2_dev; INIT_LIST_HEAD(¬ifier->waiting); INIT_LIST_HEAD(¬ifier->done); + mutex_init(¬ifier->lock); for (i = 0; i < notifier->num_subdevs; i++) { asd = notifier->subdevs[i]; @@ -173,28 +176,22 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, list_add_tail(&asd->list, ¬ifier->waiting); } - mutex_lock(&list_lock); - /* Keep also completed notifiers on the list */ list_add(¬ifier->list, ¬ifier_list); + mutex_lock(¬ifier->lock); list_for_each_entry_safe(sd, tmp, &subdev_list, async_list) { - int ret; - asd = v4l2_async_belongs(notifier, sd); if (!asd) continue; ret = v4l2_async_test_notify(notifier, sd, asd); - if (ret < 0) { - mutex_unlock(&list_lock); - return ret; - } + if (ret < 0) + break; } + mutex_unlock(¬ifier->lock); - mutex_unlock(&list_lock); - - return 0; + return ret; } EXPORT_SYMBOL(v4l2_async_notifier_register); @@ -215,7 +212,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier) "Failed to allocate device cache!\n"); } - mutex_lock(&list_lock); + mutex_lock(¬ifier->lock); list_del(¬ifier->list); @@ -242,7 +239,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier) put_device(d); } - mutex_unlock(&list_lock); + mutex_unlock(¬ifier->lock); /* * Call device_attach() to reprobe devices @@ -267,6 +264,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier) } kfree(dev); + mutex_destroy(¬ifier->lock); notifier->v4l2_dev = NULL; /* @@ -279,6 +277,7 @@ EXPORT_SYMBOL(v4l2_async_notifier_unregister); int v4l2_async_register_subdev(struct v4l2_subdev *sd) { struct v4l2_async_notifier *notifier; + struct v4l2_async_notifier *tmp; /* * No reference taken. The reference is held by the device @@ -288,24 +287,25 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd) if (!sd->of_node && sd->dev) sd->of_node = sd->dev->of_node; - mutex_lock(&list_lock); - INIT_LIST_HEAD(&sd->async_list); - list_for_each_entry(notifier, ¬ifier_list, list) { - struct v4l2_async_subdev *asd = v4l2_async_belongs(notifier, sd); + list_for_each_entry_safe(notifier, tmp, ¬ifier_list, list) { + struct v4l2_async_subdev *asd; + + /* TODO: FIXME: if this is called by ->bound() we will also iterate over the locked notifier */ + mutex_lock_nested(¬ifier->lock, SINGLE_DEPTH_NESTING); + asd = v4l2_async_belongs(notifier, sd); if (asd) { int ret = v4l2_async_test_notify(notifier, sd, asd); - mutex_unlock(&list_lock); + mutex_unlock(¬ifier->lock); return ret; } + mutex_unlock(¬ifier->lock); } /* None matched, wait for hot-plugging */ list_add(&sd->async_list, &subdev_list); - mutex_unlock(&list_lock); - return 0; } EXPORT_SYMBOL(v4l2_async_register_subdev); @@ -320,7 +320,7 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd) return; } - mutex_lock(&list_lock); + mutex_lock_nested(¬ifier->lock, SINGLE_DEPTH_NESTING); list_add(&sd->asd->list, ¬ifier->waiting); @@ -329,6 +329,6 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd) if (notifier->unbind) notifier->unbind(notifier, sd, sd->asd); - mutex_unlock(&list_lock); + mutex_unlock(¬ifier->lock); } EXPORT_SYMBOL(v4l2_async_unregister_subdev); diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h index 1d6d7da..d2178c1 100644 --- a/include/media/v4l2-async.h +++ b/include/media/v4l2-async.h @@ -71,6 +71,7 @@ struct v4l2_async_subdev { * @waiting: list of struct v4l2_async_subdev, waiting for their drivers * @done: list of struct v4l2_subdev, already probed * @list: member in a global list of notifiers + * @lock: lock hold when the notifier is being processed * @bound: a subdevice driver has successfully probed one of subdevices * @complete: all subdevices have been probed successfully * @unbind: a subdevice is leaving @@ -82,6 +83,7 @@ struct v4l2_async_notifier { struct list_head waiting; struct list_head done; struct list_head list; + struct mutex lock; int (*bound)(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd);