[media] pwc: Replace private buffer management code with videobuf2

Looking at the pwc buffer management code has made it clear to me it needed
some serious fixing. Not only was there a ton of code duplication even
internally to pwc (read and mmap wait for frame code was duplicated), the
code also was outright buggy. With the worst offender being dqbuf, which
just round robin returned all the mmap buffers, without paying any attention
to them being queued by the app with qbuf or not. And qbuf itself was a noop.

So I set out to fix this and already had some cleanups in place when
I read Jonathan Corbet's lwn article on videobuf2, this inspired me to just
rip out the buffer management code and replace it with videobuf2, greatly
reducing the amount of code, and fixing all bugs in one go:

Many thanks to Jonathan for the timely article on this !

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/media/video/pwc/pwc-uncompress.c b/drivers/media/video/pwc/pwc-uncompress.c
index 4118184951ee..d110e38c4de0 100644
--- a/drivers/media/video/pwc/pwc-uncompress.c
+++ b/drivers/media/video/pwc/pwc-uncompress.c
@@ -34,17 +34,14 @@
 #include "pwc-dec1.h"
 #include "pwc-dec23.h"
 
-int pwc_decompress(struct pwc_device *pdev)
+int pwc_decompress(struct pwc_device *pdev, struct pwc_frame_buf *fbuf)
 {
-	struct pwc_frame_buf *fbuf;
 	int n, line, col, stride;
 	void *yuv, *image;
 	u16 *src;
 	u16 *dsty, *dstu, *dstv;
 
-	fbuf = pdev->read_frame;
-	image  = pdev->image_data;
-	image += pdev->images[pdev->fill_image].offset;
+	image = vb2_plane_vaddr(&fbuf->vb, 0);
 
 	yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */
 
@@ -59,9 +56,13 @@ int pwc_decompress(struct pwc_device *pdev)
 			 * determine this using the type of the webcam */
 		memcpy(raw_frame->cmd, pdev->cmd_buf, 4);
 		memcpy(raw_frame+1, yuv, pdev->frame_size);
+		vb2_set_plane_payload(&fbuf->vb, 0,
+			pdev->frame_size + sizeof(struct pwc_raw_frame));
 		return 0;
 	}
 
+	vb2_set_plane_payload(&fbuf->vb, 0, pdev->view.size);
+
 	if (pdev->vbandlength == 0) {
 		/* Uncompressed mode.
 		 * We copy the data into the output buffer, using the viewport