diff options
| author |   Brandon Philips <brandon@ifup.org> | 2008-04-02 18:10:59 -0300 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab@infradead.org> | 2008-04-24 14:07:57 -0300 |
| commit | ce54093cefd64c1a2cb6b8c5ed1d68d2bd7a34ab (patch) | |
| tree | 886b3eaf7a05731618b95e8f24e6c33ebe8edc3e /drivers/media/video/videobuf-dma-sg.c | |
| parent | V4L/DVB (7493): videobuf: Avoid deadlock with QBUF and bring up to spec for empty queue (diff) | |
| download | linux-dev-ce54093cefd64c1a2cb6b8c5ed1d68d2bd7a34ab.tar.xz linux-dev-ce54093cefd64c1a2cb6b8c5ed1d68d2bd7a34ab.zip | |
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.c | 16 |
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 717783fa8b3e..e6ce99ff7fd1 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; |