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, 2 insertions, 2 deletions

diff --git a/Documentation/driver-api/media/v4l2-fh.rst b/Documentation/driver-api/media/v4l2-fh.rst
index a7393067f5db..afcad22ead7c 100644
--- a/Documentation/driver-api/media/v4l2-fh.rst
+++ b/Documentation/driver-api/media/v4l2-fh.rst
@@ -65,7 +65,7 @@ Example:
 		struct my_fh *my_fh = container_of(fh, struct my_fh, fh);
 
 		...
-		v4l2_fh_del(&my_fh->fh);
+		v4l2_fh_del(&my_fh->fh, file);
 		v4l2_fh_exit(&my_fh->fh);
 		kfree(my_fh);
 		return 0;
@@ -86,7 +86,7 @@ Below is a short description of the :c:type:`v4l2_fh` functions used:
   Must be called once the file handle is completely initialized.
 
 :c:func:`v4l2_fh_del <v4l2_fh_del>`
-(:c:type:`fh <v4l2_fh>`)
+(:c:type:`fh <v4l2_fh>`, struct file \*filp)
 
 - Unassociate the file handle from :c:type:`video_device`. The file handle
   exit function may now be called.