[dpdk-dev] [PATCH 1/2] net/sfc: restart RxQ in case of exception on its event queue

[Andrew Rybchenko]

Examples of recoverable exceptions are:
 - unexpected Rx event (Rx scatter abort with non-zero size,
   too big Rx descriptors batch completed)
 - Rx error due to invalid Rx descriptors push
 - Rx error due to Rx descriptor read error (e.g. unmapped Rx ring
   and denied by IOMMU)

Reviewed-by: Andrew Lee <alee at solarflare.com>
Reviewed-by: Robert Stonehouse <rstonehouse at solarflare.com>
Signed-off-by: Andrew Rybchenko <arybchenko at solarflare.com>
---
 drivers/net/sfc/sfc.h    |  6 ++++++
 drivers/net/sfc/sfc_ev.c | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/drivers/net/sfc/sfc.h b/drivers/net/sfc/sfc.h
index 29d3a6b..995dfe6 100644
--- a/drivers/net/sfc/sfc.h
+++ b/drivers/net/sfc/sfc.h
@@ -187,6 +187,12 @@ sfc_adapter_lock(struct sfc_adapter *sa)
 	rte_spinlock_lock(&sa->lock);
 }
 
+static inline int
+sfc_adapter_trylock(struct sfc_adapter *sa)
+{
+	return rte_spinlock_trylock(&sa->lock);
+}
+
 static inline void
 sfc_adapter_unlock(struct sfc_adapter *sa)
 {
diff --git a/drivers/net/sfc/sfc_ev.c b/drivers/net/sfc/sfc_ev.c
index 96b95cc..36aede8 100644
--- a/drivers/net/sfc/sfc_ev.c
+++ b/drivers/net/sfc/sfc_ev.c
@@ -30,6 +30,7 @@
 #include <rte_debug.h>
 #include <rte_cycles.h>
 #include <rte_alarm.h>
+#include <rte_branch_prediction.h>
 
 #include "efx.h"
 
@@ -320,6 +321,31 @@ sfc_ev_qpoll(struct sfc_evq *evq)
 
 	efx_ev_qpoll(evq->common, &evq->read_ptr, &sfc_ev_callbacks, evq);
 
+	if (unlikely(evq->exception) && sfc_adapter_trylock(evq->sa)) {
+		struct sfc_adapter *sa = evq->sa;
+		int rc;
+
+		if ((evq->rxq != NULL) && (evq->rxq->state & SFC_RXQ_RUNNING)) {
+			unsigned int rxq_sw_index = sfc_rxq_sw_index(evq->rxq);
+
+			sfc_warn(sa,
+				 "restart RxQ %u because of exception on its EvQ %u",
+				 rxq_sw_index, evq->evq_index);
+
+			sfc_rx_qstop(sa, rxq_sw_index);
+			rc = sfc_rx_qstart(sa, rxq_sw_index);
+			if (rc != 0)
+				sfc_err(sa, "cannot restart RxQ %u",
+					rxq_sw_index);
+		}
+
+		if (evq->exception)
+			sfc_panic(sa, "unrecoverable exception on EvQ %u",
+				  evq->evq_index);
+
+		sfc_adapter_unlock(sa);
+	}
+
 	/* Poll-mode driver does not re-prime the event queue for interrupts */
 }
 
-- 
2.5.5