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>
diff --git a/drivers/media/video/video-buf.c b/drivers/media/video/video-buf.c
index 6504a586..459786f 100644
--- a/drivers/media/video/video-buf.c
+++ b/drivers/media/video/video-buf.c
@@ -148,6 +148,8 @@
dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
data,size,dma->nr_pages);
+ dma->varea = (void *) data;
+
down_read(¤t->mm->mmap_sem);
err = get_user_pages(current,current->mm,
data & PAGE_MASK, dma->nr_pages,
@@ -285,6 +287,7 @@
vfree(dma->vmalloc);
dma->vmalloc = NULL;
+ dma->varea = NULL;
if (dma->bus_addr) {
dma->bus_addr = 0;