[PATCH 3.18 33/52] media: vb2: be sure to unlock mutex on errors

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mauro Carvalho Chehab <mchehab+sams...@kernel.org>

commit c06ef2e9acef4cda1feee2ce055b8086e33d251a upstream.

As reported by smatch:
drivers/media/common/videobuf2/videobuf2-core.c: 
drivers/media/common/videobuf2/videobuf2-core.c:2159 vb2_mmap() warn: 
inconsistent returns 'mutex:&q->mmap_lock'.
  Locked on:   line 2148
  Unlocked on: line 2100
               line 2108
               line 2113
               line 2118
               line 2156
               line 2159

There is one error condition that doesn't unlock a mutex.

Fixes: cd26d1c4d1bc ("media: vb2: vb2_mmap: move lock up")
Reviewed-by: Hans Verkuil <hverkuil-ci...@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+sams...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/media/v4l2-core/videobuf2-core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -2501,7 +2501,8 @@ int vb2_mmap(struct vb2_queue *q, struct
        if (length < (vma->vm_end - vma->vm_start)) {
                dprintk(1,
                        "MMAP invalid, as it would overflow buffer length\n");
-               return -EINVAL;
+               ret = -EINVAL;
+               goto unlock;
        }
 
        ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);