media: v4l2-mem2mem: add vb2_m2m_request_queue

For mem2mem devices we have to make sure that v4l2_m2m_try_schedule()
is called whenever a request is queued.

We do that by creating a vb2_m2m_request_queue() helper that should
be used instead of the 'normal' vb2_request_queue() helper. The m2m
helper function will call v4l2_m2m_try_schedule() as needed.

In addition we also avoid calling v4l2_m2m_try_schedule() when preparing
or queueing a buffer for a request since that is no longer needed.
Instead this helper function will do that when the request is actually
queued.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

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

@@ -387,7 +387,7 @@ static void v4l2_m2m_cancel_job(struct v4l2_m2m_ctx *m2m_ctx)
 		spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 		if (m2m_dev->m2m_ops->job_abort)
 			m2m_dev->m2m_ops->job_abort(m2m_ctx->priv);
-		dprintk("m2m_ctx %p running, will wait to complete", m2m_ctx);
+		dprintk("m2m_ctx %p running, will wait to complete\n", m2m_ctx);
 		wait_event(m2m_ctx->finished,
 				!(m2m_ctx->job_flags & TRANS_RUNNING));
 	} else if (m2m_ctx->job_flags & TRANS_QUEUED) {
@@ -478,8 +478,14 @@ int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 	int ret;
 
 	vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
+	if (!V4L2_TYPE_IS_OUTPUT(vq->type) &&
+	    (buf->flags & V4L2_BUF_FLAG_REQUEST_FD)) {
+		dprintk("%s: requests cannot be used with capture buffers\n",
+			__func__);
+		return -EPERM;
+	}
 	ret = vb2_qbuf(vq, vdev->v4l2_dev->mdev, buf);
-	if (!ret)
+	if (!ret && !(buf->flags & V4L2_BUF_FLAG_IN_REQUEST))
 		v4l2_m2m_try_schedule(m2m_ctx);
 
 	return ret;
@@ -501,14 +507,9 @@ int v4l2_m2m_prepare_buf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 {
 	struct video_device *vdev = video_devdata(file);
 	struct vb2_queue *vq;
-	int ret;
 
 	vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
-	ret = vb2_prepare_buf(vq, vdev->v4l2_dev->mdev, buf);
-	if (!ret)
-		v4l2_m2m_try_schedule(m2m_ctx);
-
-	return ret;
+	return vb2_prepare_buf(vq, vdev->v4l2_dev->mdev, buf);
 }
 EXPORT_SYMBOL_GPL(v4l2_m2m_prepare_buf);
 
@@ -952,6 +953,52 @@ void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx,
 }
 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_queue);
 
+void vb2_m2m_request_queue(struct media_request *req)
+{
+	struct media_request_object *obj, *obj_safe;
+	struct v4l2_m2m_ctx *m2m_ctx = NULL;
+
+	/*
+	 * Queue all objects. Note that buffer objects are at the end of the
+	 * objects list, after all other object types. Once buffer objects
+	 * are queued, the driver might delete them immediately (if the driver
+	 * processes the buffer at once), so we have to use
+	 * list_for_each_entry_safe() to handle the case where the object we
+	 * queue is deleted.
+	 */
+	list_for_each_entry_safe(obj, obj_safe, &req->objects, list) {
+		struct v4l2_m2m_ctx *m2m_ctx_obj;
+		struct vb2_buffer *vb;
+
+		if (!obj->ops->queue)
+			continue;
+
+		if (vb2_request_object_is_buffer(obj)) {
+			/* Sanity checks */
+			vb = container_of(obj, struct vb2_buffer, req_obj);
+			WARN_ON(!V4L2_TYPE_IS_OUTPUT(vb->vb2_queue->type));
+			m2m_ctx_obj = container_of(vb->vb2_queue,
+						   struct v4l2_m2m_ctx,
+						   out_q_ctx.q);
+			WARN_ON(m2m_ctx && m2m_ctx_obj != m2m_ctx);
+			m2m_ctx = m2m_ctx_obj;
+		}
+
+		/*
+		 * The buffer we queue here can in theory be immediately
+		 * unbound, hence the use of list_for_each_entry_safe()
+		 * above and why we call the queue op last.
+		 */
+		obj->ops->queue(obj);
+	}
+
+	WARN_ON(!m2m_ctx);
+
+	if (m2m_ctx)
+		v4l2_m2m_try_schedule(m2m_ctx);
+}
+EXPORT_SYMBOL_GPL(vb2_m2m_request_queue);
+
 /* Videobuf2 ioctl helpers */
 
 int v4l2_m2m_ioctl_reqbufs(struct file *file, void *priv,

include/media/v4l2-mem2mem.h

@@ -622,6 +622,10 @@ v4l2_m2m_dst_buf_remove_by_idx(struct v4l2_m2m_ctx *m2m_ctx, unsigned int idx)
 	return v4l2_m2m_buf_remove_by_idx(&m2m_ctx->cap_q_ctx, idx);
 }
 
+/* v4l2 request helper */
+
+void vb2_m2m_request_queue(struct media_request *req);
+
 /* v4l2 ioctl helpers */
 
 int v4l2_m2m_ioctl_reqbufs(struct file *file, void *priv,