From: Hans Verkuil <hans.verk...@cisco.com>

When compiling this for older kernels using the compatibility build
the compiler complains about uninitialized variables:

In file included from include/linux/kernel.h:20:0,
                 from include/linux/cache.h:4,
                 from include/linux/time.h:7,
                 from include/linux/input.h:13,
                 from /home/hans/work/build/media_build/v4l/compat.h:9,
                 from <command-line>:0:
/home/hans/work/build/media_build/v4l/videobuf2-core.c: In function 'vb2_mmap':
include/linux/dynamic_debug.h:60:9: warning: 'plane' may be used uninitialized 
in this function [-Wmaybe-uninitialized]
   printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__);  \
         ^
/home/hans/work/build/media_build/v4l/videobuf2-core.c:2381:23: note: 'plane' 
was declared here
  unsigned int buffer, plane;
                       ^
In file included from include/linux/kernel.h:20:0,
                 from include/linux/cache.h:4,
                 from include/linux/time.h:7,
                 from include/linux/input.h:13,
                 from /home/hans/work/build/media_build/v4l/compat.h:9,
                 from <command-line>:0:
include/linux/dynamic_debug.h:60:9: warning: 'buffer' may be used uninitialized 
in this function [-Wmaybe-uninitialized]
   printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__);  \
         ^
/home/hans/work/build/media_build/v4l/videobuf2-core.c:2381:15: note: 'buffer' 
was declared here
  unsigned int buffer, plane;
               ^

While these warnings are bogus (the call to __find_plane_by_offset will
set buffer and plane), it doesn't hurt to initialize these variables.

Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c 
b/drivers/media/v4l2-core/videobuf2-core.c
index f8f694a..40024d7 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -2378,7 +2378,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct 
*vma)
 {
        unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
        struct vb2_buffer *vb;
-       unsigned int buffer, plane;
+       unsigned int buffer = 0, plane = 0;
        int ret;
        unsigned long length;
 
-- 
1.9.2

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