V4L/DVB (5147): Make vivi driver to use vmalloced pointers

Before this patch, vivi were simulating a scatter gather DMA transfer.
While this is academic, showing how stuff really works on a real PCI 
device, this means a non-optimized code. 
There are only two memory models that vivi implements:
	1) kernel alloced memory. This is also used by read() method.
	   On this case, a vmalloc32 buffer is allocated at kernel;
	2) userspace allocated memory. This is used by most userspace apps.
	   video-buf will store this pointer.
	   a simple copy_to_user is enough to transfer data.
The third memory model scenario supported by video-buf is overlay mode. 
This model is not implemented on vivi and unlikely to be implemented on 
newer drivers, since now, most userspace apps do some post-processing 
(like de-interlacing).
After this patch, some cleanups may be done at video-buf.c to avoid 
allocating pages, when the driver doesn't need a PCI buffer. This is the 
case of vivi and usb drivers.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/media/video/video-buf.c b/drivers/media/video/video-buf.c
index 6504a5866849..459786ff459a 100644
--- a/drivers/media/video/video-buf.c
+++ b/drivers/media/video/video-buf.c
@@ -148,6 +148,8 @@ int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
         dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
                 data,size,dma->nr_pages);
 
+        dma->varea = (void *) data;
+
         down_read(&current->mm->mmap_sem);
         err = get_user_pages(current,current->mm,
                              data & PAGE_MASK, dma->nr_pages,
@@ -285,6 +287,7 @@ int videobuf_dma_free(struct videobuf_dmabuf *dma)
 
         vfree(dma->vmalloc);
         dma->vmalloc = NULL;
+        dma->varea = NULL;
 
         if (dma->bus_addr) {
                 dma->bus_addr = 0;