media: Reset file->private_data to NULL in v4l2_fh_del()

Multiple drivers that use v4l2_fh and call v4l2_fh_del() manually reset
the file->private_data pointer to NULL in their video device .release()
file operation handler. Move the code to the v4l2_fh_del() function to
avoid direct access to file->private_data in drivers. This requires
adding a file pointer argument to the function.

Changes to drivers have been generated with the following coccinelle
semantic patch:

@@
expression fh;
identifier filp;
identifier release;
type ret;
@@
ret release(..., struct file *filp, ...)
{
	<...
-	filp->private_data = NULL;
	...
-	v4l2_fh_del(fh);
+	v4l2_fh_del(fh, filp);
	...>
}

@@
expression fh;
identifier filp;
identifier release;
type ret;
@@
ret release(..., struct file *filp, ...)
{
	<...
-	v4l2_fh_del(fh);
+	v4l2_fh_del(fh, filp);
	...
-	filp->private_data = NULL;
	...>
}

@@
expression fh;
identifier filp;
identifier release;
type ret;
@@
ret release(..., struct file *filp, ...)
{
	<...
-	v4l2_fh_del(fh);
+	v4l2_fh_del(fh, filp);
	...>
}

Manual changes have been applied to Documentation/ to update the usage
patterns, to drivers/media/v4l2-core/v4l2-fh.c to update the
v4l2_fh_del() prototype and reset file->private_data, and to
include/media/v4l2-fh.h to update the v4l2_fh_del() function prototype
and its documentation.

Additionally, white space issues have been fixed manually in
drivers/usb/gadget/function/uvc_v4l2.c

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/media/v4l2-fh.h b/include/media/v4l2-fh.h
index d8fcf49f10e0..5e4c76163512 100644
--- a/include/media/v4l2-fh.h
+++ b/include/media/v4l2-fh.h
@@ -114,12 +114,15 @@ int v4l2_fh_open(struct file *filp);
  * v4l2_fh_del - Remove file handle from the list of file handles.
  *
  * @fh: pointer to &struct v4l2_fh
+ * @filp: pointer to &struct file associated with @fh
+ *
+ * The function resets filp->private_data to NULL.
  *
  * .. note::
  *    Must be called in v4l2_file_operations->release\(\) handler if the driver
  *    uses &struct v4l2_fh.
  */
-void v4l2_fh_del(struct v4l2_fh *fh);
+void v4l2_fh_del(struct v4l2_fh *fh, struct file *filp);
 
 /**
  * v4l2_fh_exit - Release resources related to a file handle.