IB/ipoib: Use NAPI in UD/TX flows

Instead of explicit call to poll_cq of the tx ring, use the NAPI mechanism
to handle the completions of each packet that has been sent to the HW.

The next major changes were taken:
 * The driver init completion function in the creation of the send CQ,
   that function triggers the napi scheduling.
 * The driver uses CQ for RX for both modes UD and CM, and CQ for TX
   for CM and UD.

Cc: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/ipoib/ipoib.h

@@ -331,7 +331,8 @@ struct ipoib_dev_priv {
 
 	struct net_device *dev;
 
-	struct napi_struct napi;
+	struct napi_struct send_napi;
+	struct napi_struct recv_napi;
 
 	unsigned long flags;
 
@@ -408,7 +409,6 @@ struct ipoib_dev_priv {
 #endif
 	u64	hca_caps;
 	struct ipoib_ethtool_st ethtool;
-	struct timer_list poll_timer;
 	unsigned max_send_sge;
 	bool sm_fullmember_sendonly_support;
 	const struct net_device_ops	*rn_ops;
@@ -475,9 +475,10 @@ extern struct workqueue_struct *ipoib_workqueue;
 
 /* functions */
 
-int ipoib_poll(struct napi_struct *napi, int budget);
-void ipoib_ib_completion(struct ib_cq *cq, void *dev_ptr);
-void ipoib_send_comp_handler(struct ib_cq *cq, void *dev_ptr);
+int ipoib_rx_poll(struct napi_struct *napi, int budget);
+int ipoib_tx_poll(struct napi_struct *napi, int budget);
+void ipoib_ib_rx_completion(struct ib_cq *cq, void *ctx_ptr);
+void ipoib_ib_tx_completion(struct ib_cq *cq, void *ctx_ptr);
 
 struct ipoib_ah *ipoib_create_ah(struct net_device *dev,
 				 struct ib_pd *pd, struct rdma_ah_attr *attr);

drivers/infiniband/ulp/ipoib/ipoib_cm.c

@@ -757,30 +757,35 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_
 		return;
 	}
 
+	if ((priv->tx_head - priv->tx_tail) == ipoib_sendq_size - 1) {
+		ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n",
+			  tx->qp->qp_num);
+		netif_stop_queue(dev);
+	}
+
 	skb_orphan(skb);
 	skb_dst_drop(skb);
 
+	if (netif_queue_stopped(dev))
+		if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP |
+				     IB_CQ_REPORT_MISSED_EVENTS)) {
+			ipoib_warn(priv, "IPoIB/CM:request notify on send CQ failed\n");
+			napi_schedule(&priv->send_napi);
+		}
+
 	rc = post_send(priv, tx, tx->tx_head & (ipoib_sendq_size - 1), tx_req);
 	if (unlikely(rc)) {
-		ipoib_warn(priv, "post_send failed, error %d\n", rc);
+		ipoib_warn(priv, "IPoIB/CM:post_send failed, error %d\n", rc);
 		++dev->stats.tx_errors;
 		ipoib_dma_unmap_tx(priv, tx_req);
 		dev_kfree_skb_any(skb);
+
+		if (netif_queue_stopped(dev))
+			netif_wake_queue(dev);
 	} else {
 		netif_trans_update(dev);
 		++tx->tx_head;
 		++priv->tx_head;
-		if ((priv->tx_head - priv->tx_tail) == ipoib_sendq_size) {
-			ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n",
-				  tx->qp->qp_num);
-			netif_stop_queue(dev);
-			rc = ib_req_notify_cq(priv->send_cq,
-				IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
-			if (rc < 0)
-				ipoib_warn(priv, "request notify on send CQ failed\n");
-			else if (rc)
-				ipoib_send_comp_handler(priv->send_cq, dev);
-		}
 	}
 }
 
@@ -815,9 +820,10 @@ void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
 
 	++tx->tx_tail;
 	++priv->tx_tail;
-	if (unlikely((priv->tx_head - priv->tx_tail) == ipoib_sendq_size >> 1) &&
-	    netif_queue_stopped(dev) &&
-	    test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
+
+	if (unlikely(netif_queue_stopped(dev) &&
+		     (priv->tx_head - priv->tx_tail) <= ipoib_sendq_size >> 1 &&
+		     test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags)))
 		netif_wake_queue(dev);
 
 	if (wc->status != IB_WC_SUCCESS &&
@@ -1046,7 +1052,7 @@ static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ipoib_
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
 	struct ib_qp_init_attr attr = {
-		.send_cq		= priv->recv_cq,
+		.send_cq		= priv->send_cq,
 		.recv_cq		= priv->recv_cq,
 		.srq			= priv->cm.srq,
 		.cap.max_send_wr	= ipoib_sendq_size,
@@ -1220,9 +1226,9 @@ static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
 		tx_req = &p->tx_ring[p->tx_tail & (ipoib_sendq_size - 1)];
 		ipoib_dma_unmap_tx(priv, tx_req);
 		dev_kfree_skb_any(tx_req->skb);
+		netif_tx_lock_bh(p->dev);
 		++p->tx_tail;
 		++priv->tx_tail;
-		netif_tx_lock_bh(p->dev);
 		if (unlikely(priv->tx_head - priv->tx_tail == ipoib_sendq_size >> 1) &&
 		    netif_queue_stopped(p->dev) &&
 		    test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))

drivers/infiniband/ulp/ipoib/ipoib_ib.c

@@ -264,7 +264,7 @@ static void ipoib_ib_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
 			likely(wc->wc_flags & IB_WC_IP_CSUM_OK))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
-	napi_gro_receive(&priv->napi, skb);
+	napi_gro_receive(&priv->recv_napi, skb);
 
 repost:
 	if (unlikely(ipoib_ib_post_receive(dev, wr_id)))
@@ -406,9 +406,10 @@ static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
 	dev_kfree_skb_any(tx_req->skb);
 
 	++priv->tx_tail;
-	if (unlikely((priv->tx_head - priv->tx_tail) == ipoib_sendq_size >> 1) &&
-	    netif_queue_stopped(dev) &&
-	    test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
+
+	if (unlikely(netif_queue_stopped(dev) &&
+		     ((priv->tx_head - priv->tx_tail) <= ipoib_sendq_size >> 1) &&
+		     test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags)))
 		netif_wake_queue(dev);
 
 	if (wc->status != IB_WC_SUCCESS &&
@@ -430,17 +431,23 @@ static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
 static int poll_tx(struct ipoib_dev_priv *priv)
 {
 	int n, i;
+	struct ib_wc *wc;
 
 	n = ib_poll_cq(priv->send_cq, MAX_SEND_CQE, priv->send_wc);
-	for (i = 0; i < n; ++i)
+	for (i = 0; i < n; ++i) {
+		wc = priv->send_wc + i;
+		if (wc->wr_id & IPOIB_OP_CM)
+			ipoib_cm_handle_tx_wc(priv->dev, priv->send_wc + i);
+		else
 			ipoib_ib_handle_tx_wc(priv->dev, priv->send_wc + i);
-
+	}
 	return n == MAX_SEND_CQE;
 }
 
-int ipoib_poll(struct napi_struct *napi, int budget)
+int ipoib_rx_poll(struct napi_struct *napi, int budget)
 {
-	struct ipoib_dev_priv *priv = container_of(napi, struct ipoib_dev_priv, napi);
+	struct ipoib_dev_priv *priv =
+		container_of(napi, struct ipoib_dev_priv, recv_napi);
 	struct net_device *dev = priv->dev;
 	int done;
 	int t;
@@ -464,8 +471,9 @@ int ipoib_poll(struct napi_struct *napi, int budget)
 					ipoib_cm_handle_rx_wc(dev, wc);
 				else
 					ipoib_ib_handle_rx_wc(dev, wc);
-			} else
-				ipoib_cm_handle_tx_wc(priv->dev, wc);
+			} else {
+				pr_warn("%s: Got unexpected wqe id\n", __func__);
+			}
 		}
 
 		if (n != t)
@@ -484,33 +492,47 @@ int ipoib_poll(struct napi_struct *napi, int budget)
 	return done;
 }
 
-void ipoib_ib_completion(struct ib_cq *cq, void *dev_ptr)
+int ipoib_tx_poll(struct napi_struct *napi, int budget)
 {
-	struct net_device *dev = dev_ptr;
-	struct ipoib_dev_priv *priv = ipoib_priv(dev);
+	struct ipoib_dev_priv *priv = container_of(napi, struct ipoib_dev_priv,
+						   send_napi);
+	struct net_device *dev = priv->dev;
+	int n, i;
+	struct ib_wc *wc;
 
-	napi_schedule(&priv->napi);
-}
+poll_more:
+	n = ib_poll_cq(priv->send_cq, MAX_SEND_CQE, priv->send_wc);
 
-static void drain_tx_cq(struct net_device *dev)
-{
-	struct ipoib_dev_priv *priv = ipoib_priv(dev);
+	for (i = 0; i < n; i++) {
+		wc = priv->send_wc + i;
+		if (wc->wr_id & IPOIB_OP_CM)
+			ipoib_cm_handle_tx_wc(dev, wc);
+		else
+			ipoib_ib_handle_tx_wc(dev, wc);
+	}
 
-	netif_tx_lock(dev);
-	while (poll_tx(priv))
-		; /* nothing */
+	if (n < budget) {
+		napi_complete(napi);
+		if (unlikely(ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP |
+					      IB_CQ_REPORT_MISSED_EVENTS)) &&
+		    napi_reschedule(napi))
+			goto poll_more;
+	}
+	return n < 0 ? 0 : n;
+}
 
-	if (netif_queue_stopped(dev))
-		mod_timer(&priv->poll_timer, jiffies + 1);
+void ipoib_ib_rx_completion(struct ib_cq *cq, void *ctx_ptr)
+{
+	struct ipoib_dev_priv *priv = ctx_ptr;
 
-	netif_tx_unlock(dev);
+	napi_schedule(&priv->recv_napi);
 }
 
-void ipoib_send_comp_handler(struct ib_cq *cq, void *dev_ptr)
+void ipoib_ib_tx_completion(struct ib_cq *cq, void *ctx_ptr)
 {
-	struct ipoib_dev_priv *priv = ipoib_priv(dev_ptr);
+	struct ipoib_dev_priv *priv = ctx_ptr;
 
-	mod_timer(&priv->poll_timer, jiffies);
+	napi_schedule(&priv->send_napi);
 }
 
 static inline int post_send(struct ipoib_dev_priv *priv,
@@ -614,14 +636,17 @@ int ipoib_send(struct net_device *dev, struct sk_buff *skb,
 	/* increase the tx_head after send success, but use it for queue state */
 	if (priv->tx_head - priv->tx_tail == ipoib_sendq_size - 1) {
 		ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
-		if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP))
-			ipoib_warn(priv, "request notify on send CQ failed\n");
 		netif_stop_queue(dev);
 	}
 
 	skb_orphan(skb);
 	skb_dst_drop(skb);
 
+	if (netif_queue_stopped(dev))
+		if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP |
+				     IB_CQ_REPORT_MISSED_EVENTS))
+			ipoib_warn(priv, "request notify on send CQ failed\n");
+
 	rc = post_send(priv, priv->tx_head & (ipoib_sendq_size - 1),
 		       address, dqpn, tx_req, phead, hlen);
 	if (unlikely(rc)) {
@@ -638,11 +663,6 @@ int ipoib_send(struct net_device *dev, struct sk_buff *skb,
 		rc = priv->tx_head;
 		++priv->tx_head;
 	}
-
-	if (unlikely(priv->tx_head - priv->tx_tail > MAX_SEND_CQE))
-		while (poll_tx(priv))
-			; /* nothing */
-
 	return rc;
 }
 
@@ -731,6 +751,22 @@ static void check_qp_movement_and_print(struct ipoib_dev_priv *priv,
 			   new_state, qp_attr.qp_state);
 }
 
+static void ipoib_napi_enable(struct net_device *dev)
+{
+	struct ipoib_dev_priv *priv = ipoib_priv(dev);
+
+	napi_enable(&priv->recv_napi);
+	napi_enable(&priv->send_napi);
+}
+
+static void ipoib_napi_disable(struct net_device *dev)
+{
+	struct ipoib_dev_priv *priv = ipoib_priv(dev);
+
+	napi_disable(&priv->recv_napi);
+	napi_disable(&priv->send_napi);
+}
+
 int ipoib_ib_dev_stop_default(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
@@ -740,7 +776,7 @@ int ipoib_ib_dev_stop_default(struct net_device *dev)
 	int i;
 
 	if (test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
-		napi_disable(&priv->napi);
+		ipoib_napi_disable(dev);
 
 	ipoib_cm_dev_stop(dev);
 
@@ -797,7 +833,6 @@ int ipoib_ib_dev_stop_default(struct net_device *dev)
 	ipoib_dbg(priv, "All sends and receives done.\n");
 
 timeout:
-	del_timer_sync(&priv->poll_timer);
 	qp_attr.qp_state = IB_QPS_RESET;
 	if (ib_modify_qp(priv->qp, &qp_attr, IB_QP_STATE))
 		ipoib_warn(priv, "Failed to modify QP to RESET state\n");
@@ -819,13 +854,6 @@ int ipoib_ib_dev_stop(struct net_device *dev)
 	return 0;
 }
 
-void ipoib_ib_tx_timer_func(struct timer_list *t)
-{
-	struct ipoib_dev_priv *priv = from_timer(priv, t, poll_timer);
-
-	drain_tx_cq(priv->dev);
-}
-
 int ipoib_ib_dev_open_default(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
@@ -850,7 +878,7 @@ int ipoib_ib_dev_open_default(struct net_device *dev)
 	}
 
 	if (!test_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
-		napi_enable(&priv->napi);
+		ipoib_napi_enable(dev);
 
 	return 0;
 out:
@@ -965,8 +993,9 @@ void ipoib_drain_cq(struct net_device *dev)
 					ipoib_cm_handle_rx_wc(dev, priv->ibwc + i);
 				else
 					ipoib_ib_handle_rx_wc(dev, priv->ibwc + i);
-			} else
-				ipoib_cm_handle_tx_wc(dev, priv->ibwc + i);
+			} else {
+				pr_warn("%s: Got unexpected wqe id\n", __func__);
+			}
 		}
 	} while (n == IPOIB_NUM_WC);
 

drivers/infiniband/ulp/ipoib/ipoib_main.c

@@ -1616,13 +1616,29 @@ static void ipoib_neigh_hash_uninit(struct net_device *dev)
 	wait_for_completion(&priv->ntbl.deleted);
 }
 
+static void ipoib_napi_add(struct net_device *dev)
+{
+	struct ipoib_dev_priv *priv = ipoib_priv(dev);
+
+	netif_napi_add(dev, &priv->recv_napi, ipoib_rx_poll, IPOIB_NUM_WC);
+	netif_napi_add(dev, &priv->send_napi, ipoib_tx_poll, MAX_SEND_CQE);
+}
+
+static void ipoib_napi_del(struct net_device *dev)
+{
+	struct ipoib_dev_priv *priv = ipoib_priv(dev);
+
+	netif_napi_del(&priv->recv_napi);
+	netif_napi_del(&priv->send_napi);
+}
+
 static void ipoib_dev_uninit_default(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
 
 	ipoib_transport_dev_cleanup(dev);
 
-	netif_napi_del(&priv->napi);
+	ipoib_napi_del(dev);
 
 	ipoib_cm_dev_cleanup(dev);
 
@@ -1637,7 +1653,7 @@ static int ipoib_dev_init_default(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
 
-	netif_napi_add(dev, &priv->napi, ipoib_poll, NAPI_POLL_WEIGHT);
+	ipoib_napi_add(dev);
 
 	/* Allocate RX/TX "rings" to hold queued skbs */
 	priv->rx_ring =	kzalloc(ipoib_recvq_size * sizeof *priv->rx_ring,
@@ -1665,8 +1681,6 @@ static int ipoib_dev_init_default(struct net_device *dev)
 	priv->dev->dev_addr[2] = (priv->qp->qp_num >>  8) & 0xff;
 	priv->dev->dev_addr[3] = (priv->qp->qp_num) & 0xff;
 
-	timer_setup(&priv->poll_timer, ipoib_ib_tx_timer_func, 0);
-
 	return 0;
 
 out_tx_ring_cleanup:
@@ -1676,7 +1690,7 @@ static int ipoib_dev_init_default(struct net_device *dev)
 	kfree(priv->rx_ring);
 
 out:
-	netif_napi_del(&priv->napi);
+	ipoib_napi_del(dev);
 	return -ENOMEM;
 }
 

drivers/infiniband/ulp/ipoib/ipoib_verbs.c

@@ -156,7 +156,7 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 	};
 	struct ib_cq_init_attr cq_attr = {};
 
-	int ret, size;
+	int ret, size, req_vec;
 	int i;
 
 	size = ipoib_recvq_size + 1;
@@ -171,17 +171,21 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 		if (ret != -ENOSYS)
 			return -ENODEV;
 
+	req_vec = (priv->port - 1) * 2;
+
 	cq_attr.cqe = size;
-	priv->recv_cq = ib_create_cq(priv->ca, ipoib_ib_completion, NULL,
-				     dev, &cq_attr);
+	cq_attr.comp_vector = req_vec % priv->ca->num_comp_vectors;
+	priv->recv_cq = ib_create_cq(priv->ca, ipoib_ib_rx_completion, NULL,
+				     priv, &cq_attr);
 	if (IS_ERR(priv->recv_cq)) {
 		printk(KERN_WARNING "%s: failed to create receive CQ\n", ca->name);
 		goto out_cm_dev_cleanup;
 	}
 
 	cq_attr.cqe = ipoib_sendq_size;
-	priv->send_cq = ib_create_cq(priv->ca, ipoib_send_comp_handler, NULL,
-				     dev, &cq_attr);
+	cq_attr.comp_vector = (req_vec + 1) % priv->ca->num_comp_vectors;
+	priv->send_cq = ib_create_cq(priv->ca, ipoib_ib_tx_completion, NULL,
+				     priv, &cq_attr);
 	if (IS_ERR(priv->send_cq)) {
 		printk(KERN_WARNING "%s: failed to create send CQ\n", ca->name);
 		goto out_free_recv_cq;
@@ -208,6 +212,9 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 		goto out_free_send_cq;
 	}
 
+	if (ib_req_notify_cq(priv->send_cq, IB_CQ_NEXT_COMP))
+		goto out_free_send_cq;
+
 	for (i = 0; i < MAX_SKB_FRAGS + 1; ++i)
 		priv->tx_sge[i].lkey = priv->pd->local_dma_lkey;