cxgb4vf: Implement "Unhandled Interrupts" statistic

Implement "Unhandled Interrupts" statistic so we can detect when the
hardware tells us that it things we have work to do but we don't find
anything ...

Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cxgb4vf/cxgb4vf_main.c b/drivers/net/cxgb4vf/cxgb4vf_main.c
index bd73ff5..e988031 100644
--- a/drivers/net/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/cxgb4vf/cxgb4vf_main.c
@@ -1790,7 +1790,7 @@
 		  (rxq[qs].rspq.netdev
 		   ? rxq[qs].rspq.netdev->name
 		   : "N/A"));
-		R3("u", "RspQNullInts", rspq.unhandled_irqs);
+		R3("u", "RspQNullInts:", rspq.unhandled_irqs);
 		R("RxPackets:", stats.pkts);
 		R("RxCSO:", stats.rx_cso);
 		R("VLANxtract:", stats.vlan_ex);
@@ -1814,14 +1814,16 @@
 		const struct sge_rspq *evtq = &adapter->sge.fw_evtq;
 
 		seq_printf(seq, "%-8s %16s\n", "QType:", "FW event queue");
-		/* no real response queue statistics available to display */
+		seq_printf(seq, "%-16s %8u\n", "RspQNullInts:",
+			   evtq->unhandled_irqs);
 		seq_printf(seq, "%-16s %8u\n", "RspQ CIdx:", evtq->cidx);
 		seq_printf(seq, "%-16s %8u\n", "RspQ Gen:", evtq->gen);
 	} else if (r == 1) {
 		const struct sge_rspq *intrq = &adapter->sge.intrq;
 
 		seq_printf(seq, "%-8s %16s\n", "QType:", "Interrupt Queue");
-		/* no real response queue statistics available to display */
+		seq_printf(seq, "%-16s %8u\n", "RspQNullInts:",
+			   intrq->unhandled_irqs);
 		seq_printf(seq, "%-16s %8u\n", "RspQ CIdx:", intrq->cidx);
 		seq_printf(seq, "%-16s %8u\n", "RspQ Gen:", intrq->gen);
 	}
diff --git a/drivers/net/cxgb4vf/sge.c b/drivers/net/cxgb4vf/sge.c
index 4bc1858..37c6354 100644
--- a/drivers/net/cxgb4vf/sge.c
+++ b/drivers/net/cxgb4vf/sge.c
@@ -1772,6 +1772,9 @@
 	} else
 		intr_params = QINTR_TIMER_IDX(SGE_TIMER_UPD_CIDX);
 
+	if (unlikely(work_done == 0))
+		rspq->unhandled_irqs++;
+
 	t4_write_reg(rspq->adapter,
 		     T4VF_SGE_BASE_ADDR + SGE_VF_GTS,
 		     CIDXINC(work_done) |