media: vb2: keep track of timestamp status

If a stream is stopped, or if a USERPTR/DMABUF buffer is queued
backed by a different user address or dmabuf fd, then the timestamp
should be skipped by vb2_find_timestamp since the memory it refers
to is no longer valid.

So keep track of a 'copied_timestamp' state: it is set when the
timestamp is copied from an output to a capture buffer, and is
cleared when it is no longer valid.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/common/videobuf2/videobuf2-core.c

@@ -1041,6 +1041,7 @@ static int __prepare_userptr(struct vb2_buffer *vb)
 		if (vb->planes[plane].mem_priv) {
 			if (!reacquired) {
 				reacquired = true;
+				vb->copied_timestamp = 0;
 				call_void_vb_qop(vb, buf_cleanup, vb);
 			}
 			call_void_memop(vb, put_userptr, vb->planes[plane].mem_priv);
@@ -1165,6 +1166,7 @@ static int __prepare_dmabuf(struct vb2_buffer *vb)
 
 		if (!reacquired) {
 			reacquired = true;
+			vb->copied_timestamp = 0;
 			call_void_vb_qop(vb, buf_cleanup, vb);
 		}
 
@@ -1942,6 +1944,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
 		if (vb->request)
 			media_request_put(vb->request);
 		vb->request = NULL;
+		vb->copied_timestamp = 0;
 	}
 }
 

drivers/media/common/videobuf2/videobuf2-v4l2.c

@@ -604,7 +604,8 @@ int vb2_find_timestamp(const struct vb2_queue *q, u64 timestamp,
 	unsigned int i;
 
 	for (i = start_idx; i < q->num_buffers; i++)
-		if (q->bufs[i]->timestamp == timestamp)
+		if (q->bufs[i]->copied_timestamp &&
+		    q->bufs[i]->timestamp == timestamp)
 			return i;
 	return -1;
 }

drivers/media/v4l2-core/v4l2-mem2mem.c

@@ -992,6 +992,7 @@ void v4l2_m2m_buf_copy_metadata(const struct vb2_v4l2_buffer *out_vb,
 	cap_vb->field = out_vb->field;
 	cap_vb->flags &= ~mask;
 	cap_vb->flags |= out_vb->flags & mask;
+	cap_vb->vb2_buf.copied_timestamp = 1;
 }
 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_copy_metadata);
 

include/media/videobuf2-core.h

@@ -262,6 +262,8 @@ struct vb2_buffer {
 	 * prepared:		this buffer has been prepared, i.e. the
 	 *			buf_prepare op was called. It is cleared again
 	 *			after the 'buf_finish' op is called.
+	 * copied_timestamp:	the timestamp of this capture buffer was copied
+	 *			from an output buffer.
 	 * queued_entry:	entry on the queued buffers list, which holds
 	 *			all buffers queued from userspace
 	 * done_entry:		entry on the list that stores all buffers ready
@@ -271,6 +273,7 @@ struct vb2_buffer {
 	enum vb2_buffer_state	state;
 	unsigned int		synced:1;
 	unsigned int		prepared:1;
+	unsigned int		copied_timestamp:1;
 
 	struct vb2_plane	planes[VB2_MAX_PLANES];
 	struct list_head	queued_entry;