svn commit: r362204 - head/sys/dev/virtio/network

[Vincenzo Maffione]

Author: vmaffione
Date: Mon Jun 15 19:46:34 2020
New Revision: 362204
URL: https://svnweb.freebsd.org/changeset/base/362204

Log:
  if_vtnet: let vtnet_rx_vq_intr() and vtnet_rxq_tq_intr() share code
  
  Since the two functions are similar, introduce a common function
  (vtnet_rx_vq_process()) to share common code.
  This also improves locking, by ensuring vrxs_rescheduled is accessed
  under the RXQ lock, and taskqueue_enqueue() is not called under the
  lock (therefore avoiding a spurious duplicate lock warning).
  
  Reported by:	jrtc27
  MFC after:	2 weeks

Modified:
  head/sys/dev/virtio/network/if_vtnet.c

Modified: head/sys/dev/virtio/network/if_vtnet.c
==============================================================================
--- head/sys/dev/virtio/network/if_vtnet.c	Mon Jun 15 19:38:48 2020	(r362203)
+++ head/sys/dev/virtio/network/if_vtnet.c	Mon Jun 15 19:46:34 2020	(r362204)
@@ -128,6 +128,7 @@ static int	vtnet_rxq_merged_eof(struct vtnet_rxq *, st
 static void	vtnet_rxq_input(struct vtnet_rxq *, struct mbuf *,
 		    struct virtio_net_hdr *);
 static int	vtnet_rxq_eof(struct vtnet_rxq *);
+static void	vtnet_rx_vq_process(struct vtnet_rxq *rxq, int tries);
 static void	vtnet_rx_vq_intr(void *);
 static void	vtnet_rxq_tq_intr(void *, int);
 
@@ -1915,20 +1916,17 @@ vtnet_rxq_eof(struct vtnet_rxq *rxq)
 }
 
 static void
-vtnet_rx_vq_intr(void *xrxq)
+vtnet_rx_vq_process(struct vtnet_rxq *rxq, int tries)
 {
 	struct vtnet_softc *sc;
-	struct vtnet_rxq *rxq;
 	struct ifnet *ifp;
-	int tries, more;
+	int more;
 #ifdef DEV_NETMAP
 	int nmirq;
 #endif /* DEV_NETMAP */
 
-	rxq = xrxq;
 	sc = rxq->vtnrx_sc;
 	ifp = sc->vtnet_ifp;
-	tries = 0;
 
 	if (__predict_false(rxq->vtnrx_id >= sc->vtnet_act_vq_pairs)) {
 		/*
@@ -1976,58 +1974,32 @@ again:
 		 * This is an occasional condition or race (when !more),
 		 * so retry a few times before scheduling the taskqueue.
 		 */
-		if (tries++ < VTNET_INTR_DISABLE_RETRIES)
+		if (tries-- > 0)
 			goto again;
 
-		VTNET_RXQ_UNLOCK(rxq);
 		rxq->vtnrx_stats.vrxs_rescheduled++;
+		VTNET_RXQ_UNLOCK(rxq);
 		taskqueue_enqueue(rxq->vtnrx_tq, &rxq->vtnrx_intrtask);
 	} else
 		VTNET_RXQ_UNLOCK(rxq);
 }
 
 static void
-vtnet_rxq_tq_intr(void *xrxq, int pending)
+vtnet_rx_vq_intr(void *xrxq)
 {
-	struct vtnet_softc *sc;
 	struct vtnet_rxq *rxq;
-	struct ifnet *ifp;
-	int more;
-#ifdef DEV_NETMAP
-	int nmirq;
-#endif /* DEV_NETMAP */
 
 	rxq = xrxq;
-	sc = rxq->vtnrx_sc;
-	ifp = sc->vtnet_ifp;
+	vtnet_rx_vq_process(rxq, VTNET_INTR_DISABLE_RETRIES);
+}
 
-	VTNET_RXQ_LOCK(rxq);
+static void
+vtnet_rxq_tq_intr(void *xrxq, int pending)
+{
+	struct vtnet_rxq *rxq;
 
-#ifdef DEV_NETMAP
-	nmirq = netmap_rx_irq(ifp, rxq->vtnrx_id, &more);
-	if (nmirq != NM_IRQ_PASS) {
-		VTNET_RXQ_UNLOCK(rxq);
-		if (nmirq == NM_IRQ_RESCHED) {
-			taskqueue_enqueue(rxq->vtnrx_tq, &rxq->vtnrx_intrtask);
-		}
-		return;
-	}
-#endif /* DEV_NETMAP */
-
-	if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) {
-		VTNET_RXQ_UNLOCK(rxq);
-		return;
-	}
-
-	more = vtnet_rxq_eof(rxq);
-	if (more || vtnet_rxq_enable_intr(rxq) != 0) {
-		if (!more)
-			vtnet_rxq_disable_intr(rxq);
-		rxq->vtnrx_stats.vrxs_rescheduled++;
-		taskqueue_enqueue(rxq->vtnrx_tq, &rxq->vtnrx_intrtask);
-	}
-
-	VTNET_RXQ_UNLOCK(rxq);
+	rxq = xrxq;
+	vtnet_rx_vq_process(rxq, 0);
 }
 
 static int