RDMA/nes: Forward packets for a new connection with stale APBVT entry

Under heavy traffic, there is a small windows when an APBVT entry is
not yet removed and a new connection is established.  Packets for the
new connection are dropped until APBVT entry is removed.  This patch
will forward the packets instead of dropping them.

Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Chien Tung <chien.tin.tung@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

3 files changed, 45 insertions, 43 deletions

diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index c259ddc8dd88..f34fa6f77a81 100644
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -86,7 +86,7 @@ static int mini_cm_accept(struct nes_cm_core *, struct ietf_mpa_frame *,
         struct nes_cm_node *);
 static int mini_cm_reject(struct nes_cm_core *, struct ietf_mpa_frame *,
         struct nes_cm_node *);
-static void mini_cm_recv_pkt(struct nes_cm_core *, struct nes_vnic *,
+static int mini_cm_recv_pkt(struct nes_cm_core *, struct nes_vnic *,
         struct sk_buff *);
 static int mini_cm_dealloc_core(struct nes_cm_core *);
 static int mini_cm_get(struct nes_cm_core *);
@@ -2076,7 +2076,7 @@ static int mini_cm_close(struct nes_cm_core *cm_core, struct nes_cm_node *cm_nod
  * recv_pkt - recv an ETHERNET packet, and process it through CM
  * node state machine
  */
-static void mini_cm_recv_pkt(struct nes_cm_core *cm_core,
+static int mini_cm_recv_pkt(struct nes_cm_core *cm_core,
         struct nes_vnic *nesvnic, struct sk_buff *skb)
 {
         struct nes_cm_node *cm_node = NULL;
@@ -2084,23 +2084,16 @@ static void mini_cm_recv_pkt(struct nes_cm_core *cm_core,
         struct iphdr *iph;
         struct tcphdr *tcph;
         struct nes_cm_info nfo;
+        int skb_handled = 1;
 
         if (!skb)
-                return;
+                return 0;
         if (skb->len < sizeof(struct iphdr) + sizeof(struct tcphdr)) {
-                dev_kfree_skb_any(skb);
-                return;
+                return 0;
         }
 
         iph = (struct iphdr *)skb->data;
         tcph = (struct tcphdr *)(skb->data + sizeof(struct iphdr));
-        skb_reset_network_header(skb);
-        skb_set_transport_header(skb, sizeof(*tcph));
-        if (!tcph) {
-                dev_kfree_skb_any(skb);
-                return;
-        }
-        skb->len = ntohs(iph->tot_len);
 
         nfo.loc_addr = ntohl(iph->daddr);
         nfo.loc_port = ntohs(tcph->dest);
@@ -2121,23 +2114,21 @@ static void mini_cm_recv_pkt(struct nes_cm_core *cm_core,
                         /* Only type of packet accepted are for */
                         /* the PASSIVE open (syn only) */
                         if ((!tcph->syn) || (tcph->ack)) {
-                                cm_packets_dropped++;
+                                skb_handled = 0;
                                 break;
                         }
                         listener = find_listener(cm_core, nfo.loc_addr,
                                 nfo.loc_port,
                                 NES_CM_LISTENER_ACTIVE_STATE);
-                        if (listener) {
-                                nfo.cm_id = listener->cm_id;
-                                nfo.conn_type = listener->conn_type;
-                        } else {
-                                nes_debug(NES_DBG_CM, "Unable to find listener "
-                                        "for the pkt\n");
-                                cm_packets_dropped++;
-                                dev_kfree_skb_any(skb);
+                        if (!listener) {
+                                nfo.cm_id = NULL;
+                                nfo.conn_type = 0;
+                                nes_debug(NES_DBG_CM, "Unable to find listener for the pkt\n");
+                                skb_handled = 0;
                                 break;
                         }
-
+                        nfo.cm_id = listener->cm_id;
+                        nfo.conn_type = listener->conn_type;
                         cm_node = make_cm_node(cm_core, nesvnic, &nfo,
                                 listener);
                         if (!cm_node) {
@@ -2163,9 +2154,13 @@ static void mini_cm_recv_pkt(struct nes_cm_core *cm_core,
                         dev_kfree_skb_any(skb);
                         break;
                 }
+                skb_reset_network_header(skb);
+                skb_set_transport_header(skb, sizeof(*tcph));
+                skb->len = ntohs(iph->tot_len);
                 process_packet(cm_node, skb, cm_core);
                 rem_ref_cm_node(cm_core, cm_node);
         } while (0);
+        return skb_handled;
 }
 
 
@@ -2985,15 +2980,16 @@ int nes_destroy_listen(struct iw_cm_id *cm_id)
  */
 int nes_cm_recv(struct sk_buff *skb, struct net_device *netdevice)
 {
+        int rc = 0;
         cm_packets_received++;
         if ((g_cm_core) && (g_cm_core->api)) {
-                g_cm_core->api->recv_pkt(g_cm_core, netdev_priv(netdevice), skb);
+                rc = g_cm_core->api->recv_pkt(g_cm_core, netdev_priv(netdevice), skb);
         } else {
                 nes_debug(NES_DBG_CM, "Unable to process packet for CM,"
                                 " cm is not setup properly.\n");
         }
 
-        return 0;
+        return rc;
 }
 
 
diff --git a/drivers/infiniband/hw/nes/nes_cm.h b/drivers/infiniband/hw/nes/nes_cm.h
index 25e2493abc6a..3a20a7883976 100644
--- a/drivers/infiniband/hw/nes/nes_cm.h
+++ b/drivers/infiniband/hw/nes/nes_cm.h
@@ -397,7 +397,7 @@ struct nes_cm_ops {
                         struct nes_cm_node *);
         int (*reject)(struct nes_cm_core *, struct ietf_mpa_frame *,
                         struct nes_cm_node *);
-        void (*recv_pkt)(struct nes_cm_core *, struct nes_vnic *,
+        int (*recv_pkt)(struct nes_cm_core *, struct nes_vnic *,
                         struct sk_buff *);
         int (*destroy_cm_core)(struct nes_cm_core *);
         int (*get)(struct nes_cm_core *);
diff --git a/drivers/infiniband/hw/nes/nes_hw.c b/drivers/infiniband/hw/nes/nes_hw.c
index 7c49cc882d75..8f70ff2dcc58 100644
--- a/drivers/infiniband/hw/nes/nes_hw.c
+++ b/drivers/infiniband/hw/nes/nes_hw.c
@@ -2700,27 +2700,33 @@ void nes_nic_ce_handler(struct nes_device *nesdev, struct nes_hw_nic_cq *cq)
                                                         pkt_type, (pkt_type & NES_PKT_TYPE_APBVT_MASK)); */
 
                                 if ((pkt_type & NES_PKT_TYPE_APBVT_MASK) == NES_PKT_TYPE_APBVT_BITS) {
-                                        nes_cm_recv(rx_skb, nesvnic->netdev);
+                                        if (nes_cm_recv(rx_skb, nesvnic->netdev))
+                                                rx_skb = NULL;
+                                }
+                                if (rx_skb == NULL)
+                                        goto skip_rx_indicate0;
+
+
+                                if ((cqe_misc & NES_NIC_CQE_TAG_VALID) &&
+                                    (nesvnic->vlan_grp != NULL)) {
+                                        vlan_tag = (u16)(le32_to_cpu(
+                                                        cq->cq_vbase[head].cqe_words[NES_NIC_CQE_TAG_PKT_TYPE_IDX])
+                                                        >> 16);
+                                        nes_debug(NES_DBG_CQ, "%s: Reporting stripped VLAN packet. Tag = 0x%04X\n",
+                                                        nesvnic->netdev->name, vlan_tag);
+                                        if (nes_use_lro)
+                                                lro_vlan_hwaccel_receive_skb(&nesvnic->lro_mgr, rx_skb,
+                                                                nesvnic->vlan_grp, vlan_tag, NULL);
+                                        else
+                                                nes_vlan_rx(rx_skb, nesvnic->vlan_grp, vlan_tag);
                                 } else {
-                                        if ((cqe_misc & NES_NIC_CQE_TAG_VALID) && (nesvnic->vlan_grp != NULL)) {
-                                                vlan_tag = (u16)(le32_to_cpu(
-                                                                cq->cq_vbase[head].cqe_words[NES_NIC_CQE_TAG_PKT_TYPE_IDX])
-                                                                >> 16);
-                                                nes_debug(NES_DBG_CQ, "%s: Reporting stripped VLAN packet. Tag = 0x%04X\n",
-                                                                nesvnic->netdev->name, vlan_tag);
-                                                if (nes_use_lro)
-                                                        lro_vlan_hwaccel_receive_skb(&nesvnic->lro_mgr, rx_skb,
-                                                                        nesvnic->vlan_grp, vlan_tag, NULL);
-                                                else
-                                                        nes_vlan_rx(rx_skb, nesvnic->vlan_grp, vlan_tag);
-                                        } else {
-                                                if (nes_use_lro)
-                                                        lro_receive_skb(&nesvnic->lro_mgr, rx_skb, NULL);
-                                                else
-                                                        nes_netif_rx(rx_skb);
-                                        }
+                                        if (nes_use_lro)
+                                                lro_receive_skb(&nesvnic->lro_mgr, rx_skb, NULL);
+                                        else
+                                                nes_netif_rx(rx_skb);
                                 }
 
+skip_rx_indicate0:
                                 nesvnic->netdev->last_rx = jiffies;
                                 /* nesvnic->netstats.rx_packets++; */
                                 /* nesvnic->netstats.rx_bytes += rx_pkt_size; */