media: vim2m: only cancel work if it is for right context

cancel_delayed_work_sync() was called for any queue, but it should only
be called for the queue that is associated with the currently running job.

Otherwise, if two filehandles are streaming at the same time, then closing the
first will cancel the work which might still be running for a job from the
second filehandle. As a result the second filehandle will never be able to
finish the job and an attempt to stop streaming on that second filehandle will
stall.

Fixes: 52117be6 ("media: vim2m: use cancel_delayed_work_sync instead of flush_schedule_work")
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org>      # for v4.20 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/vim2m.c

@@ -807,7 +807,9 @@ static void vim2m_stop_streaming(struct vb2_queue *q)
 	struct vb2_v4l2_buffer *vbuf;
 	unsigned long flags;
 
-	cancel_delayed_work_sync(&dev->work_run);
+	if (v4l2_m2m_get_curr_priv(dev->m2m_dev) == ctx)
+		cancel_delayed_work_sync(&dev->work_run);
+
 	for (;;) {
 		if (V4L2_TYPE_IS_OUTPUT(q->type))
 			vbuf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);