nvme-core: add async event trace helper

This patch adds a new event for nvme async event notification.
We print the async event in the decoded format when we recognize
the event otherwise we just dump the result.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -3408,16 +3408,21 @@ static void nvme_fw_act_work(struct work_struct *work)
 
 static void nvme_handle_aen_notice(struct nvme_ctrl *ctrl, u32 result)
 {
-	switch ((result & 0xff00) >> 8) {
+	u32 aer_notice_type = (result & 0xff00) >> 8;
+
+	switch (aer_notice_type) {
 	case NVME_AER_NOTICE_NS_CHANGED:
+		trace_nvme_async_event(ctrl, aer_notice_type);
 		set_bit(NVME_AER_NOTICE_NS_CHANGED, &ctrl->events);
 		nvme_queue_scan(ctrl);
 		break;
 	case NVME_AER_NOTICE_FW_ACT_STARTING:
+		trace_nvme_async_event(ctrl, aer_notice_type);
 		queue_work(nvme_wq, &ctrl->fw_act_work);
 		break;
 #ifdef CONFIG_NVME_MULTIPATH
 	case NVME_AER_NOTICE_ANA:
+		trace_nvme_async_event(ctrl, aer_notice_type);
 		if (!ctrl->ana_log_buf)
 			break;
 		queue_work(nvme_wq, &ctrl->ana_work);
@@ -3432,11 +3437,12 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
 		volatile union nvme_result *res)
 {
 	u32 result = le32_to_cpu(res->u32);
+	u32 aer_type = result & 0x07;
 
 	if (le16_to_cpu(status) >> 1 != NVME_SC_SUCCESS)
 		return;
 
-	switch (result & 0x7) {
+	switch (aer_type) {
 	case NVME_AER_NOTICE:
 		nvme_handle_aen_notice(ctrl, result);
 		break;
@@ -3444,6 +3450,7 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
 	case NVME_AER_SMART:
 	case NVME_AER_CSS:
 	case NVME_AER_VS:
+		trace_nvme_async_event(ctrl, aer_type);
 		ctrl->aen_result = result;
 		break;
 	default:

drivers/nvme/host/trace.h

@@ -156,6 +156,34 @@ TRACE_EVENT(nvme_complete_rq,
 
 );
 
+#define aer_name(aer) { aer, #aer }
+
+TRACE_EVENT(nvme_async_event,
+	TP_PROTO(struct nvme_ctrl *ctrl, u32 result),
+	TP_ARGS(ctrl, result),
+	TP_STRUCT__entry(
+		__field(int, ctrl_id)
+		__field(u32, result)
+	),
+	TP_fast_assign(
+		__entry->ctrl_id = ctrl->instance;
+		__entry->result = result;
+	),
+	TP_printk("nvme%d: NVME_AEN=%#08x [%s]",
+		__entry->ctrl_id, __entry->result,
+		__print_symbolic(__entry->result,
+		aer_name(NVME_AER_NOTICE_NS_CHANGED),
+		aer_name(NVME_AER_NOTICE_ANA),
+		aer_name(NVME_AER_NOTICE_FW_ACT_STARTING),
+		aer_name(NVME_AER_ERROR),
+		aer_name(NVME_AER_SMART),
+		aer_name(NVME_AER_CSS),
+		aer_name(NVME_AER_VS))
+	)
+);
+
+#undef aer_name
+
 #endif /* _TRACE_NVME_H */
 
 #undef TRACE_INCLUDE_PATH