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authorBrandon Philips <brandon@ifup.org>2008-04-02 18:10:59 -0300
committerMauro Carvalho Chehab <mchehab@infradead.org>2008-04-24 14:07:57 -0300
commitce54093cefd64c1a2cb6b8c5ed1d68d2bd7a34ab (patch)
tree886b3eaf7a05731618b95e8f24e6c33ebe8edc3e /drivers/media/video/videobuf-dma-sg.c
parent137d1cb19d9da163ce6cb57a6fa1e6a3468af6a4 (diff)
V4L/DVB (7494): videobuf-dma-sg.c: Avoid NULL dereference and add comment about backwards compatibility
Signed-off-by: Brandon Philips <bphilips@suse.de> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Diffstat (limited to 'drivers/media/video/videobuf-dma-sg.c')
-rw-r--r--drivers/media/video/videobuf-dma-sg.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/media/video/videobuf-dma-sg.c b/drivers/media/video/videobuf-dma-sg.c
index 717783fa8b3..e6ce99ff7fd 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -546,6 +546,14 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
goto done;
}
+ /* This function maintains backwards compatibility with V4L1 and will
+ * map more than one buffer if the vma length is equal to the combined
+ * size of multiple buffers than it will map them together. See
+ * VIDIOCGMBUF in the v4l spec
+ *
+ * TODO: Allow drivers to specify if they support this mode
+ */
+
/* look for first buffer to map */
for (first = 0; first < VIDEO_MAX_FRAME; first++) {
if (NULL == q->bufs[first])
@@ -590,10 +598,16 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
if (NULL == map)
goto done;
- for (size = 0, i = first; i <= last; size += q->bufs[i++]->bsize) {
+
+ size = 0;
+ for (i = first; i <= last; i++) {
+ if (NULL == q->bufs[i])
+ continue;
q->bufs[i]->map = map;
q->bufs[i]->baddr = vma->vm_start + size;
+ size += q->bufs[i]->bsize;
}
+
map->count = 1;
map->start = vma->vm_start;
map->end = vma->vm_end;