[libcamera-devel] [PATCH v2 2/2] libcamera: pipeline_handler: Make lock() and unlock() thread-safe
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Mon Dec 27 00:12:55 CET 2021
The PipelineHandler lock() and unlock() functions are documented as
thread-safe, but they're not. Fix them using a mutex.
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
Changes since v1:
- Add thread safety annotation
- Comment that lockOwner_ does not indicate ownership of lock_
---
include/libcamera/internal/pipeline_handler.h | 4 +++-
src/libcamera/pipeline_handler.cpp | 5 +++++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
index a7331cedfb16..e5b8ffb4db3d 100644
--- a/include/libcamera/internal/pipeline_handler.h
+++ b/include/libcamera/internal/pipeline_handler.h
@@ -14,6 +14,7 @@
#include <sys/types.h>
#include <vector>
+#include <libcamera/base/mutex.h>
#include <libcamera/base/object.h>
#include <libcamera/controls.h>
@@ -88,7 +89,8 @@ private:
const char *name_;
- bool lockOwner_;
+ Mutex lock_;
+ bool lockOwner_ LIBCAMERA_TSA_GUARDED_BY(lock_); /* *Not* ownership of lock_ */
friend class PipelineHandlerFactory;
};
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index a9241ac62979..03e4b9e66aa6 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -11,6 +11,7 @@
#include <sys/sysmacros.h>
#include <libcamera/base/log.h>
+#include <libcamera/base/mutex.h>
#include <libcamera/base/utils.h>
#include <libcamera/camera.h>
@@ -155,6 +156,8 @@ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator,
*/
bool PipelineHandler::lock()
{
+ MutexLocker locker(lock_);
+
/* Do not allow nested locking in the same libcamera instance. */
if (lockOwner_)
return false;
@@ -183,6 +186,8 @@ bool PipelineHandler::lock()
*/
void PipelineHandler::unlock()
{
+ MutexLocker locker(lock_);
+
if (!lockOwner_)
return;
--
Regards,
Laurent Pinchart
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