media: amphion: lock and check m2m_ctx in event handler

driver needs to cancel vpu before releasing the vpu instance,
so call v4l2_m2m_ctx_release() first,
to handle the redundant event triggered after m2m_ctx is released.

lock and check m2m_ctx in the event handler.

Fixes: 3cd08451 ("media: amphion: add vpu v4l2 m2m support")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/amphion/vpu_msgs.c

@@ -43,6 +43,7 @@ static void vpu_session_handle_mem_request(struct vpu_inst *inst, struct vpu_rpc
 		  req_data.ref_frame_num,
 		  req_data.act_buf_size,
 		  req_data.act_buf_num);
+	vpu_inst_lock(inst);
 	call_void_vop(inst, mem_request,
 		      req_data.enc_frame_size,
 		      req_data.enc_frame_num,
@@ -50,6 +51,7 @@ static void vpu_session_handle_mem_request(struct vpu_inst *inst, struct vpu_rpc
 		      req_data.ref_frame_num,
 		      req_data.act_buf_size,
 		      req_data.act_buf_num);
+	vpu_inst_unlock(inst);
 }
 
 static void vpu_session_handle_stop_done(struct vpu_inst *inst, struct vpu_rpc_event *pkt)

drivers/media/platform/amphion/vpu_v4l2.c

@@ -327,8 +327,12 @@ int vpu_process_capture_buffer(struct vpu_inst *inst)
 
 struct vb2_v4l2_buffer *vpu_next_src_buf(struct vpu_inst *inst)
 {
-	struct vb2_v4l2_buffer *src_buf = v4l2_m2m_next_src_buf(inst->fh.m2m_ctx);
+	struct vb2_v4l2_buffer *src_buf = NULL;
 
+	if (!inst->fh.m2m_ctx)
+		return NULL;
+
+	src_buf = v4l2_m2m_next_src_buf(inst->fh.m2m_ctx);
 	if (!src_buf || vpu_get_buffer_state(src_buf) == VPU_BUF_STATE_IDLE)
 		return NULL;
 
@@ -351,7 +355,7 @@ void vpu_skip_frame(struct vpu_inst *inst, int count)
 	enum vb2_buffer_state state;
 	int i = 0;
 
-	if (count <= 0)
+	if (count <= 0 || !inst->fh.m2m_ctx)
 		return;
 
 	while (i < count) {