[PATCH 05/17] media: v4l2-subdev: Provide a cleanup-friendly get_frame_desc

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Provide a cleanup-friendly get_frame_desc() API function that returns a
frame descriptor that can be automatically released using __free().

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 36 ++++++++++++++++++++++++---
 include/media/v4l2-subdev.h           | 22 +++++++++++-----
 2 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 012ff6fb2988..a49aaad595af 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -2691,8 +2691,8 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_get_frame_desc_passthrough);
 
-int v4l2_subdev_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
-			       struct v4l2_mbus_frame_desc *desc)
+static int __v4l2_subdev_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+					struct v4l2_mbus_frame_desc *desc)
 {
 	struct v4l2_subdev_format subdev_fmt = {
 		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
@@ -2747,9 +2747,33 @@ int v4l2_subdev_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
 
 	return 0;
 }
+
+struct v4l2_mbus_frame_desc *
+v4l2_subdev_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+			   enum v4l2_mbus_frame_desc_type type)
+{
+	struct v4l2_mbus_frame_desc *desc;
+	int ret;
+
+	desc = kzalloc_obj(*desc, GFP_KERNEL);
+	if (!desc)
+		return ERR_PTR(-ENOMEM);
+
+	desc->type = type;
+	desc->entry = desc->entry_mem;
+	desc->len_entries = ARRAY_SIZE(desc->entry_mem);
+
+	ret = __v4l2_subdev_get_frame_desc(sd, pad, desc);
+	if (ret) {
+		kfree(desc);
+		return ERR_PTR(ret);
+	}
+
+	return desc;
+}
 EXPORT_SYMBOL_GPL(v4l2_subdev_get_frame_desc);
 
-void v4l2_subdev_free_frame_desc(struct v4l2_mbus_frame_desc *desc)
+static void __v4l2_subdev_free_frame_desc(struct v4l2_mbus_frame_desc *desc)
 {
 	if (desc->entry != desc->entry_mem)
 		kfree(desc->entry);
@@ -2757,6 +2781,12 @@ void v4l2_subdev_free_frame_desc(struct v4l2_mbus_frame_desc *desc)
 	desc->entry = NULL;
 	desc->len_entries = desc->num_entries = 0;
 }
+
+void v4l2_subdev_free_frame_desc(struct v4l2_mbus_frame_desc *desc)
+{
+	__v4l2_subdev_free_frame_desc(desc);
+	kfree(desc);
+}
 EXPORT_SYMBOL_GPL(v4l2_subdev_free_frame_desc);
 
 #endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index bd97510c7024..6e40420c2fcc 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -8,6 +8,7 @@
 #ifndef _V4L2_SUBDEV_H
 #define _V4L2_SUBDEV_H
 
+#include <linux/cleanup.h>
 #include <linux/types.h>
 #include <linux/v4l2-subdev.h>
 #include <media/media-entity.h>
@@ -1794,7 +1795,7 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
  * v4l2_subdev_get_frame_desc() - Get a frame descriptor for a pad
  * @sd: The sub-device
  * @pad: The number of the pad in @sd from which to obtain the frame descriptor
- * @desc: A pointer to a frame descriptor, with its type field set
+ * @type: The type of the frame descriptor
  *
  * Obtain a frame descriptor from a sub-device. If the sub-device supports the
  * get_frame_desc pad operation, its result is returned, just like calling it
@@ -1810,20 +1811,29 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
  * each frame descriptor obtained by calling this function using
  * v4l2_subdev_free_frame_desc().
  *
- * Return: %0 on success or negative error code on failure.
+ * Use __free() to release the frame descriptor automatically:
+ *
+ * struct v4l2_mbus_frame_desc *desc __free(v4l2_subdev_free_frame_desc) =
+ *	v4l2_subdev_get_frame_desc(sd, pad, desc);
+ *
+ * Return: The frame descriptor on success or a negative error code on failure.
  */
-int v4l2_subdev_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
-			       struct v4l2_mbus_frame_desc *desc);
+struct v4l2_mbus_frame_desc *
+v4l2_subdev_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+			   enum v4l2_mbus_frame_desc_type type);
 
 /**
  * v4l2_subdev_free_frame_desc() - Release the memory of a frame descriptor
  * @desc: A pointer to a frame descriptor
  *
- * Release the frame descriptor entries in a frame descriptor. The number of
- * entries in the descriptor are set to 0 again.
+ * Release the frame descriptor entries and the frame descriptor itself.
  */
 void v4l2_subdev_free_frame_desc(struct v4l2_mbus_frame_desc *desc);
 
+DEFINE_FREE(v4l2_subdev_free_frame_desc, struct v4l2_mbus_frame_desc *, \
+	    if (!IS_ERR_OR_NULL(_T))					\
+		    v4l2_subdev_free_frame_desc(_T))
+
 #endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
 
 #endif /* CONFIG_MEDIA_CONTROLLER */
-- 
2.47.3