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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans Verkuil <hans.verkuil@cisco.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 33/46] Revert "media: videobuf2-core: dont call memop finish when queueing"
Date:   Mon, 26 Nov 2018 11:51:22 +0100
Message-Id: <20181126105049.243773279@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 f7ca1fab4808..4df4a1f402be 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 ||
-- 
2.17.1