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Message-Id: <827307083c45909d1197a463a07dffc2f4fe3c83.1452105878.git.shuahkh@osg.samsung.com>
Date:	Wed,  6 Jan 2016 13:26:56 -0700
From:	Shuah Khan <shuahkh@....samsung.com>
To:	mchehab@....samsung.com, tiwai@...e.com, clemens@...isch.de,
	hans.verkuil@...co.com, laurent.pinchart@...asonboard.com,
	sakari.ailus@...ux.intel.com, javier@....samsung.com
Cc:	Shuah Khan <shuahkh@....samsung.com>, pawel@...iak.com,
	m.szyprowski@...sung.com, kyungmin.park@...sung.com,
	perex@...ex.cz, arnd@...db.de, dan.carpenter@...cle.com,
	tvboxspy@...il.com, crope@....fi, ruchandani.tina@...il.com,
	corbet@....net, chehabrafael@...il.com, k.kozlowski@...sung.com,
	stefanr@...6.in-berlin.de, inki.dae@...sung.com,
	jh1009.sung@...sung.com, elfring@...rs.sourceforge.net,
	prabhakar.csengg@...il.com, sw0312.kim@...sung.com,
	p.zabel@...gutronix.de, ricardo.ribalda@...il.com,
	labbott@...oraproject.org, pierre-louis.bossart@...ux.intel.com,
	ricard.wanderlof@...s.com, julian@...st.de, takamichiho@...il.com,
	dominic.sacre@....de, misterpib@...il.com, daniel@...que.org,
	gtmkramer@...all.nl, normalperson@...t.net, joe@...po.co.uk,
	linuxbugs@...tgam.net, johan@...ud.se,
	linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
	linux-api@...r.kernel.org, alsa-devel@...a-project.org
Subject: [PATCH 07/31] media: Media Controller non-locking __media_entity_pipeline_start/stop()

Add non-locking __media_entity_pipeline_start/stop() interfaces
to be called from code paths that hold the graph_mutex. For this
change, the media_entity_pipeline_start() routine is renamed to
__media_entity_pipeline_start() minus the graph_mutex lock and
unlock. media_entity_pipeline_start() now calls the non-locking
__media_entity_pipeline_start() holding the graph_lock. The stop
interface, media_entity_pipeline_stop() routine is renamed to
__media_entity_pipeline_stop() minus the graph_mutex lock and
unlock. media_entity_pipeline_stop() now calls the non-locking
__media_entity_pipeline_stop() holding the graph_lock.

Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
---
 drivers/media/media-entity.c | 34 ++++++++++++++++++++++++----------
 include/media/media-entity.h | 12 ++++++++++++
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index b8769aa..270ade2 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -361,8 +361,8 @@ EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
  * Pipeline management
  */
 
-__must_check int media_entity_pipeline_start(struct media_entity *entity,
-					     struct media_pipeline *pipe)
+__must_check int __media_entity_pipeline_start(struct media_entity *entity,
+					       struct media_pipeline *pipe)
 {
 	struct media_device *mdev = entity->graph_obj.mdev;
 	struct media_entity_graph *graph = &pipe->graph;
@@ -370,8 +370,6 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 	struct media_link *link;
 	int ret;
 
-	mutex_lock(&mdev->graph_mutex);
-
 	if (!pipe->streaming_count++) {
 		ret = media_entity_graph_walk_init(&pipe->graph, mdev);
 		if (ret)
@@ -452,8 +450,6 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 		}
 	}
 
-	mutex_unlock(&mdev->graph_mutex);
-
 	return 0;
 
 error:
@@ -483,19 +479,28 @@ error_graph_walk_start:
 	if (!--pipe->streaming_count)
 		media_entity_graph_walk_cleanup(graph);
 
-	mutex_unlock(&mdev->graph_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__media_entity_pipeline_start);
 
+__must_check int media_entity_pipeline_start(struct media_entity *entity,
+					     struct media_pipeline *pipe)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+	int ret;
+
+	mutex_lock(&mdev->graph_mutex);
+	ret = __media_entity_pipeline_start(entity, pipe);
+	mutex_unlock(&mdev->graph_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 
-void media_entity_pipeline_stop(struct media_entity *entity)
+void __media_entity_pipeline_stop(struct media_entity *entity)
 {
-	struct media_device *mdev = entity->graph_obj.mdev;
 	struct media_entity_graph *graph = &entity->pipe->graph;
 	struct media_pipeline *pipe = entity->pipe;
 
-	mutex_lock(&mdev->graph_mutex);
 
 	WARN_ON(!pipe->streaming_count);
 	media_entity_graph_walk_start(graph, entity);
@@ -512,6 +517,15 @@ void media_entity_pipeline_stop(struct media_entity *entity)
 	if (!--pipe->streaming_count)
 		media_entity_graph_walk_cleanup(graph);
 
+}
+EXPORT_SYMBOL_GPL(__media_entity_pipeline_stop);
+
+void media_entity_pipeline_stop(struct media_entity *entity)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+
+	mutex_lock(&mdev->graph_mutex);
+	__media_entity_pipeline_stop(entity);
 	mutex_unlock(&mdev->graph_mutex);
 }
 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 79dd81f..3f4f577 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -781,6 +781,12 @@ media_entity_graph_walk_next(struct media_entity_graph *graph);
  */
 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 					     struct media_pipeline *pipe);
+/**
+ * non-locking __media_entity_pipeline_start() can be called from
+ * code paths that hold the graph_mutex
+ */
+__must_check int __media_entity_pipeline_start(struct media_entity *entity,
+					       struct media_pipeline *pipe);
 
 /**
  * media_entity_pipeline_stop - Mark a pipeline as not streaming
@@ -797,6 +803,12 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 void media_entity_pipeline_stop(struct media_entity *entity);
 
 /**
+ * non-locking __media_entity_pipeline_stop() can be called from
+ * code paths that hold the graph_mutex
+ */
+void __media_entity_pipeline_stop(struct media_entity *entity);
+
+/**
  * media_devnode_create() - creates and initializes a device node interface
  *
  * @mdev:	pointer to struct &media_device
-- 
2.5.0

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