[PATCH 2/2] drivers/media/common: Add missing video_device_release

[Julia Lawall]

From: Julia Lawall <julia@xxxxxxx>

Video_device_alloc returns the result of a kzalloc.  In this case, the
value is stored in a local variable which is not copied elsewhere before
the point of the error return (video_register_device does not save its
first argument anywhere if it returns a negative value).  Thus, a
video_device_release it needed before the error return.


The problem was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
type T,T1,T2;
identifier E;
statement S;
expression x1,x2,x3;
int ret;
@@

  T E;
  ...
* E = video_device_alloc(...);
  if (E == NULL) S
  ... when != video_device_release(...,(T1)E,...)
      when != if (E != NULL) { ... video_device_release(...,(T1)E,...); ...}
      when != x1 = (T1)E
      when != E = x3;
      when any
  if (...) {
    ... when != video_device_release(...,(T2)E,...)
        when != if (E != NULL) { ... video_device_release(...,(T2)E,...); ...}
        when != x2 = (T2)E
(
*   return;
|
*   return ret;
)
  }
// </smpl>

Signed-off-by: Julia Lawall <julia@xxxxxxx>
---

diff -u -p a/drivers/media/common/saa7146_fops.c b/drivers/media/common/saa7146_fops.c
--- a/drivers/media/common/saa7146_fops.c	2007-10-22 11:25:10.000000000 +0200
+++ b/drivers/media/common/saa7146_fops.c	2008-01-01 14:20:33.000000000 +0100
@@ -538,6 +538,7 @@ int saa7146_register_device(struct video
 	// fixme: -1 should be an insmod parameter *for the extension* (like "video_nr");
 	if (video_register_device(vfd, type, -1) < 0) {
 		ERR(("cannot register v4l2 device. skipping.\n"));
+		video_device_release(vfd);
 		return -1;
 	}
 
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