[PATCH for v4.9] Revert "media: videobuf2-core: don't call memop 'finish' when queueing"

[PATCH for v4.9] Revert "media: videobuf2-core: don't call memop 'finish' when queueing"

[Hans Verkuil]

This reverts commit 9ac47200b51cb09d2f15dbefa67e0412741d98aa.

This commit fixes a bug in upstream commit a136f59c0a1f ("vb2: Move
buffer cache synchronisation to prepare from queue") which isn't
present in 4.9.

So as a result you get an UNBALANCED message in the kernel log if
this patch is applied:

vb2:   counters for queue ffffffc0f3687478, buffer 3: UNBALANCED!
vb2:     buf_init: 1 buf_cleanup: 1 buf_prepare: 805 buf_finish: 805
vb2:     buf_queue: 806 buf_done: 806
vb2:     alloc: 0 put: 0 prepare: 806 finish: 805 mmap: 0
vb2:     get_userptr: 0 put_userptr: 0
vb2:     attach_dmabuf: 1 detach_dmabuf: 1 map_dmabuf: 805 unmap_dmabuf: 805
vb2:     get_dmabuf: 0 num_users: 1609 vaddr: 0 cookie: 805

Reverting this patch solves this regression.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
---
Probably two reasons why this slipped through:

1) The patch was missing a Fixes: tag
2) I was probably CC-ed about this when it was about to be added to 4.9
   but didn't realize that that was wrong.
---
 drivers/media/v4l2-core/videobuf2-core.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index f7ca1fa..4df4a1f 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -914,12 +914,9 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 	dprintk(4, "done processing on buffer %d, state: %d\n",
 			vb->index, state);

-	if (state != VB2_BUF_STATE_QUEUED &&
-	    state != VB2_BUF_STATE_REQUEUEING) {
-		/* sync buffers */
-		for (plane = 0; plane < vb->num_planes; ++plane)
-			call_void_memop(vb, finish, vb->planes[plane].mem_priv);
-	}
+	/* sync buffers */
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_void_memop(vb, finish, vb->planes[plane].mem_priv);

 	spin_lock_irqsave(&q->done_lock, flags);
 	if (state == VB2_BUF_STATE_QUEUED ||
-- 
2.10.2

Re: [PATCH for v4.9] Revert "media: videobuf2-core: don't call memop 'finish' when queueing"

[Sasha Levin]

On Thu, Nov 22, 2018 at 12:43:56PM +0100, Hans Verkuil wrote:
>This reverts commit 9ac47200b51cb09d2f15dbefa67e0412741d98aa.
>
>This commit fixes a bug in upstream commit a136f59c0a1f ("vb2: Move
>buffer cache synchronisation to prepare from queue") which isn't
>present in 4.9.
>
>So as a result you get an UNBALANCED message in the kernel log if
>this patch is applied:
>
>vb2:   counters for queue ffffffc0f3687478, buffer 3: UNBALANCED!
>vb2:     buf_init: 1 buf_cleanup: 1 buf_prepare: 805 buf_finish: 805
>vb2:     buf_queue: 806 buf_done: 806
>vb2:     alloc: 0 put: 0 prepare: 806 finish: 805 mmap: 0
>vb2:     get_userptr: 0 put_userptr: 0
>vb2:     attach_dmabuf: 1 detach_dmabuf: 1 map_dmabuf: 805 unmap_dmabuf: 805
>vb2:     get_dmabuf: 0 num_users: 1609 vaddr: 0 cookie: 805
>
>Reverting this patch solves this regression.
>
>Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

I've queued both reverts to their respective branches, thank you.

--
Thanks,
Sasha