habanalabs: count dropped CS because max CS in-flight

There is a case where the user reaches the maximum number of CS in-flight.
In that case, the driver rejects the new CS of the user with EAGAIN. Count
that event so the user can query the driver later to see if it happened.
Reviewed-by: Tomer Tayar <ttayar@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/misc/habanalabs/common/command_submission.c

@@ -252,6 +252,8 @@ static void cs_counters_aggregate(struct hl_device *hdev, struct hl_ctx *ctx)
 			ctx->cs_counters.parsing_drop_cnt;
 	hdev->aggregated_cs_counters.queue_full_drop_cnt +=
 			ctx->cs_counters.queue_full_drop_cnt;
+	hdev->aggregated_cs_counters.max_cs_in_flight_drop_cnt +=
+			ctx->cs_counters.max_cs_in_flight_drop_cnt;
 }
 
 static void cs_do_release(struct kref *ref)
@@ -431,8 +433,9 @@ static int allocate_cs(struct hl_device *hdev, struct hl_ctx *ctx,
 				(hdev->asic_prop.max_pending_cs - 1)];
 
 	if (other && !completion_done(&other->completion)) {
-		dev_dbg(hdev->dev,
+		dev_dbg_ratelimited(hdev->dev,
 			"Rejecting CS because of too many in-flights CS\n");
+		ctx->cs_counters.max_cs_in_flight_drop_cnt++;
 		rc = -EAGAIN;
 		goto free_fence;
 	}

include/uapi/misc/habanalabs.h

@@ -401,12 +401,14 @@ struct hl_info_sync_manager {
  * @parsing_drop_cnt: dropped due to error in packet parsing
  * @queue_full_drop_cnt: dropped due to queue full
  * @device_in_reset_drop_cnt: dropped due to device in reset
+ * @max_cs_in_flight_drop_cnt: dropped due to maximum CS in-flight
  */
 struct hl_cs_counters {
 	__u64 out_of_mem_drop_cnt;
 	__u64 parsing_drop_cnt;
 	__u64 queue_full_drop_cnt;
 	__u64 device_in_reset_drop_cnt;
+	__u64 max_cs_in_flight_drop_cnt;
 };
 
 struct hl_info_cs_counters {