v4l2: v4l2_compat_manager: Store V4L2CameraFile in mmaps_

The mmaps_ map stores a pointer to the V4L2CameraProxy to avoid
increasing the reference count on the V4L2CameraFile shared pointer
needlessly. While this provides a small optimization, it prevents
accessing the V4L2CameraFile from the munmap() function which doesn't
take an fd as argument.

To prepare for improved debugging that will require access to
V4L2CameraFile in munmap(), store the V4L2CameraFile pointer in mmaps_.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

src/v4l2/v4l2_compat_manager.cpp

@@ -198,11 +198,7 @@ void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
 	if (map == MAP_FAILED)
 		return map;
 
-	/*
+	mmaps_[map] = file;
-	 * Map to V4L2CameraProxy directly to prevent adding more references
-	 * to V4L2CameraFile.
-	 */
-	mmaps_[map] = file->proxy();
 	return map;
 }
 
@@ -212,9 +208,9 @@ int V4L2CompatManager::munmap(void *addr, size_t length)
 	if (device == mmaps_.end())
 		return fops_.munmap(addr, length);
 
-	V4L2CameraProxy *proxy = device->second;
+	V4L2CameraFile *file = device->second.get();
 
-	int ret = proxy->munmap(addr, length);
+	int ret = file->proxy()->munmap(addr, length);
 	if (ret < 0)
 		return ret;
 

src/v4l2/v4l2_compat_manager.h

@@ -65,5 +65,5 @@ private:
 
 	std::vector<std::unique_ptr<V4L2CameraProxy>> proxies_;
 	std::map<int, std::shared_ptr<V4L2CameraFile>> files_;
-	std::map<void *, V4L2CameraProxy *> mmaps_;
+	std::map<void *, std::shared_ptr<V4L2CameraFile>> mmaps_;
 };