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Commit ce54093c authored by Brandon Philips's avatar Brandon Philips Committed by Mauro Carvalho Chehab
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V4L/DVB (7494): videobuf-dma-sg.c: Avoid NULL dereference and add comment... 


V4L/DVB (7494): videobuf-dma-sg.c: Avoid NULL dereference and add comment about backwards compatibility

Signed-off-by: default avatarBrandon Philips <bphilips@suse.de>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent 137d1cb1

drivers/media/video/videobuf-dma-sg.c

+15 −1
Original line number Diff line number Diff line
@@ -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;