media: cedrus: Forbid setting new formats on busy queues

Check that our queues are not busy before setting the format or return
EBUSY if that's the case. This ensures that our format can't change
once buffers are allocated for the queue.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/staging/media/sunxi/cedrus/cedrus_video.c

@@ -282,8 +282,13 @@ static int cedrus_s_fmt_vid_cap(struct file *file, void *priv,
 {
 	struct cedrus_ctx *ctx = cedrus_file2ctx(file);
 	struct cedrus_dev *dev = ctx->dev;
+	struct vb2_queue *vq;
 	int ret;
 
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	if (vb2_is_busy(vq))
+		return -EBUSY;
+
 	ret = cedrus_try_fmt_vid_cap(file, priv, f);
 	if (ret)
 		return ret;
@@ -299,8 +304,13 @@ static int cedrus_s_fmt_vid_out(struct file *file, void *priv,
 				struct v4l2_format *f)
 {
 	struct cedrus_ctx *ctx = cedrus_file2ctx(file);
+	struct vb2_queue *vq;
 	int ret;
 
+	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
+	if (vb2_is_busy(vq))
+		return -EBUSY;
+
 	ret = cedrus_try_fmt_vid_out(file, priv, f);
 	if (ret)
 		return ret;