RDMA/cxgb4: Fix LE hash collision bug for passive open connection

It establishes passive open connection through firmware work request. Passive
open connection will go through this path as now instead of listening server we
create a server filter which will redirect the incoming SYN packet to the
offload queue. After this driver tries to establish the connection using
firmware work request.

Signed-off-by: Vipul Pandya <vipul@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 442 insertions, 55 deletions

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index 4878704b6d70..036ddd281529 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -38,10 +38,12 @@
 #include <linux/inetdevice.h>
 #include <linux/ip.h>
 #include <linux/tcp.h>
+#include <linux/if_vlan.h>
 
 #include <net/neighbour.h>
 #include <net/netevent.h>
 #include <net/route.h>
+#include <net/tcp.h>
 
 #include "iw_cxgb4.h"
 
@@ -1569,13 +1571,14 @@ static int pass_open_rpl(struct c4iw_dev *dev, struct sk_buff *skb)
 	struct c4iw_listen_ep *ep = lookup_stid(t, stid);
 
 	if (!ep) {
-		printk(KERN_ERR MOD "stid %d lookup failure!\n", stid);
-		return 0;
+		PDBG("%s stid %d lookup failure!\n", __func__, stid);
+		goto out;
 	}
 	PDBG("%s ep %p status %d error %d\n", __func__, ep,
 	     rpl->status, status2errno(rpl->status));
 	c4iw_wake_up(&ep->com.wr_wait, status2errno(rpl->status));
 
+out:
 	return 0;
 }
 
@@ -1779,15 +1782,23 @@ static int pass_accept_req(struct c4iw_dev *dev, struct sk_buff *skb)
 	unsigned int hwtid = GET_TID(req);
 	struct dst_entry *dst;
 	struct rtable *rt;
-	__be32 local_ip, peer_ip;
+	__be32 local_ip, peer_ip = 0;
 	__be16 local_port, peer_port;
 	int err;
+	u16 peer_mss = ntohs(req->tcpopt.mss);
 
 	parent_ep = lookup_stid(t, stid);
-	PDBG("%s parent ep %p tid %u\n", __func__, parent_ep, hwtid);
-
+	if (!parent_ep) {
+		PDBG("%s connect request on invalid stid %d\n", __func__, stid);
+		goto reject;
+	}
 	get_4tuple(req, &local_ip, &peer_ip, &local_port, &peer_port);
 
+	PDBG("%s parent ep %p hwtid %u laddr 0x%x raddr 0x%x lport %d " \
+	     "rport %d peer_mss %d\n", __func__, parent_ep, hwtid,
+	     ntohl(local_ip), ntohl(peer_ip), ntohs(local_port),
+	     ntohs(peer_port), peer_mss);
+
 	if (state_read(&parent_ep->com) != LISTEN) {
 		printk(KERN_ERR "%s - listening ep not in LISTEN\n",
 		       __func__);
@@ -1821,6 +1832,9 @@ static int pass_accept_req(struct c4iw_dev *dev, struct sk_buff *skb)
 		goto reject;
 	}
 
+	if (peer_mss && child_ep->mtu > (peer_mss + 40))
+		child_ep->mtu = peer_mss + 40;
+
 	state_set(&child_ep->com, CONNECTING);
 	child_ep->com.dev = dev;
 	child_ep->com.cm_id = NULL;
@@ -1861,6 +1875,9 @@ static int pass_establish(struct c4iw_dev *dev, struct sk_buff *skb)
 	ep->snd_seq = be32_to_cpu(req->snd_isn);
 	ep->rcv_seq = be32_to_cpu(req->rcv_isn);
 
+	PDBG("%s ep %p hwtid %u tcp_opt 0x%02x\n", __func__, ep, tid,
+	     ntohs(req->tcp_opt));
+
 	set_emss(ep, ntohs(req->tcp_opt));
 
 	dst_confirm(ep->dst);
@@ -2478,7 +2495,6 @@ int c4iw_create_listen(struct iw_cm_id *cm_id, int backlog)
 	struct c4iw_dev *dev = to_c4iw_dev(cm_id->device);
 	struct c4iw_listen_ep *ep;
 
-
 	might_sleep();
 
 	ep = alloc_ep(sizeof(*ep), GFP_KERNEL);
@@ -2497,30 +2513,49 @@ int c4iw_create_listen(struct iw_cm_id *cm_id, int backlog)
 	/*
 	 * Allocate a server TID.
 	 */
-	ep->stid = cxgb4_alloc_stid(dev->rdev.lldi.tids, PF_INET, ep);
+	if (dev->rdev.lldi.enable_fw_ofld_conn)
+		ep->stid = cxgb4_alloc_sftid(dev->rdev.lldi.tids, PF_INET, ep);
+	else
+		ep->stid = cxgb4_alloc_stid(dev->rdev.lldi.tids, PF_INET, ep);
+
 	if (ep->stid == -1) {
 		printk(KERN_ERR MOD "%s - cannot alloc stid.\n", __func__);
 		err = -ENOMEM;
 		goto fail2;
 	}
-
 	state_set(&ep->com, LISTEN);
-	c4iw_init_wr_wait(&ep->com.wr_wait);
-	err = cxgb4_create_server(ep->com.dev->rdev.lldi.ports[0], ep->stid,
-				  ep->com.local_addr.sin_addr.s_addr,
-				  ep->com.local_addr.sin_port,
-				  ep->com.dev->rdev.lldi.rxq_ids[0]);
-	if (err)
-		goto fail3;
-
-	/* wait for pass_open_rpl */
-	err = c4iw_wait_for_reply(&ep->com.dev->rdev, &ep->com.wr_wait, 0, 0,
-				  __func__);
+	if (dev->rdev.lldi.enable_fw_ofld_conn) {
+		do {
+			err = cxgb4_create_server_filter(
+				ep->com.dev->rdev.lldi.ports[0], ep->stid,
+				ep->com.local_addr.sin_addr.s_addr,
+				ep->com.local_addr.sin_port,
+				ep->com.dev->rdev.lldi.rxq_ids[0]);
+			if (err == -EBUSY) {
+				set_current_state(TASK_UNINTERRUPTIBLE);
+				schedule_timeout(usecs_to_jiffies(100));
+			}
+		} while (err == -EBUSY);
+	} else {
+		c4iw_init_wr_wait(&ep->com.wr_wait);
+		err = cxgb4_create_server(ep->com.dev->rdev.lldi.ports[0],
+				ep->stid, ep->com.local_addr.sin_addr.s_addr,
+				ep->com.local_addr.sin_port,
+				ep->com.dev->rdev.lldi.rxq_ids[0]);
+		if (!err)
+			err = c4iw_wait_for_reply(&ep->com.dev->rdev,
+						  &ep->com.wr_wait,
+						  0, 0, __func__);
+	}
 	if (!err) {
 		cm_id->provider_data = ep;
 		goto out;
 	}
-fail3:
+	pr_err("%s cxgb4_create_server/filter failed err %d " \
+	       "stid %d laddr %08x lport %d\n", \
+	       __func__, err, ep->stid,
+	       ntohl(ep->com.local_addr.sin_addr.s_addr),
+	       ntohs(ep->com.local_addr.sin_port));
 	cxgb4_free_stid(ep->com.dev->rdev.lldi.tids, ep->stid, PF_INET);
 fail2:
 	cm_id->rem_ref(cm_id);
@@ -2539,12 +2574,18 @@ int c4iw_destroy_listen(struct iw_cm_id *cm_id)
 
 	might_sleep();
 	state_set(&ep->com, DEAD);
-	c4iw_init_wr_wait(&ep->com.wr_wait);
-	err = listen_stop(ep);
-	if (err)
-		goto done;
-	err = c4iw_wait_for_reply(&ep->com.dev->rdev, &ep->com.wr_wait, 0, 0,
-				  __func__);
+	if (ep->com.dev->rdev.lldi.enable_fw_ofld_conn) {
+		err = cxgb4_remove_server_filter(
+			ep->com.dev->rdev.lldi.ports[0], ep->stid,
+			ep->com.dev->rdev.lldi.rxq_ids[0], 0);
+	} else {
+		c4iw_init_wr_wait(&ep->com.wr_wait);
+		err = listen_stop(ep);
+		if (err)
+			goto done;
+		err = c4iw_wait_for_reply(&ep->com.dev->rdev, &ep->com.wr_wait,
+					  0, 0, __func__);
+	}
 	cxgb4_free_stid(ep->com.dev->rdev.lldi.tids, ep->stid, PF_INET);
 done:
 	cm_id->rem_ref(cm_id);
@@ -2621,10 +2662,299 @@ int c4iw_ep_disconnect(struct c4iw_ep *ep, int abrupt, gfp_t gfp)
 	return ret;
 }
 
-static int async_event(struct c4iw_dev *dev, struct sk_buff *skb)
+static void active_ofld_conn_reply(struct c4iw_dev *dev, struct sk_buff *skb,
+			struct cpl_fw6_msg_ofld_connection_wr_rpl *req)
+{
+	struct c4iw_ep *ep;
+
+	ep = (struct c4iw_ep *)lookup_atid(dev->rdev.lldi.tids, req->tid);
+	if (!ep)
+		return;
+
+	switch (req->retval) {
+	case FW_ENOMEM:
+	case FW_EADDRINUSE:
+		PDBG("%s ofld conn wr ret %d\n", __func__, req->retval);
+		break;
+	default:
+		pr_info("%s unexpected ofld conn wr retval %d\n",
+		       __func__, req->retval);
+		break;
+	}
+	connect_reply_upcall(ep, status2errno(req->retval));
+}
+
+static void passive_ofld_conn_reply(struct c4iw_dev *dev, struct sk_buff *skb,
+			struct cpl_fw6_msg_ofld_connection_wr_rpl *req)
+{
+	struct sk_buff *rpl_skb;
+	struct cpl_pass_accept_req *cpl;
+	int ret;
+
+	rpl_skb = (struct sk_buff *)cpu_to_be64(req->cookie);
+	BUG_ON(!rpl_skb);
+	if (req->retval) {
+		PDBG("%s passive open failure %d\n", __func__, req->retval);
+		kfree_skb(rpl_skb);
+	} else {
+		cpl = (struct cpl_pass_accept_req *)cplhdr(rpl_skb);
+		OPCODE_TID(cpl) = htonl(MK_OPCODE_TID(CPL_PASS_ACCEPT_REQ,
+						      htonl(req->tid)));
+		ret = pass_accept_req(dev, rpl_skb);
+		if (!ret)
+			kfree_skb(rpl_skb);
+	}
+	return;
+}
+
+static int deferred_fw6_msg(struct c4iw_dev *dev, struct sk_buff *skb)
 {
 	struct cpl_fw6_msg *rpl = cplhdr(skb);
-	c4iw_ev_dispatch(dev, (struct t4_cqe *)&rpl->data[0]);
+	struct cpl_fw6_msg_ofld_connection_wr_rpl *req;
+
+	switch (rpl->type) {
+	case FW6_TYPE_CQE:
+		c4iw_ev_dispatch(dev, (struct t4_cqe *)&rpl->data[0]);
+		break;
+	case FW6_TYPE_OFLD_CONNECTION_WR_RPL:
+		req = (struct cpl_fw6_msg_ofld_connection_wr_rpl *)rpl->data;
+		switch (req->t_state) {
+		case TCP_SYN_SENT:
+			active_ofld_conn_reply(dev, skb, req);
+			break;
+		case TCP_SYN_RECV:
+			passive_ofld_conn_reply(dev, skb, req);
+			break;
+		default:
+			pr_err("%s unexpected ofld conn wr state %d\n",
+			       __func__, req->t_state);
+			break;
+		}
+		break;
+	}
+	return 0;
+}
+
+static void build_cpl_pass_accept_req(struct sk_buff *skb, int stid , u8 tos)
+{
+	u32 l2info;
+	u16 vlantag, len, hdr_len;
+	u8 intf;
+	struct cpl_rx_pkt *cpl = cplhdr(skb);
+	struct cpl_pass_accept_req *req;
+	struct tcp_options_received tmp_opt;
+
+	/* Store values from cpl_rx_pkt in temporary location. */
+	vlantag = cpl->vlan;
+	len = cpl->len;
+	l2info  = cpl->l2info;
+	hdr_len = cpl->hdr_len;
+	intf = cpl->iff;
+
+	__skb_pull(skb, sizeof(*req) + sizeof(struct rss_header));
+
+	/*
+	 * We need to parse the TCP options from SYN packet.
+	 * to generate cpl_pass_accept_req.
+	 */
+	memset(&tmp_opt, 0, sizeof(tmp_opt));
+	tcp_clear_options(&tmp_opt);
+	tcp_parse_options(skb, &tmp_opt, 0, 0, NULL);
+
+	req = (struct cpl_pass_accept_req *)__skb_push(skb, sizeof(*req));
+	memset(req, 0, sizeof(*req));
+	req->l2info = cpu_to_be16(V_SYN_INTF(intf) |
+			 V_SYN_MAC_IDX(G_RX_MACIDX(htonl(l2info))) |
+			 F_SYN_XACT_MATCH);
+	req->hdr_len = cpu_to_be32(V_SYN_RX_CHAN(G_RX_CHAN(htonl(l2info))) |
+				V_TCP_HDR_LEN(G_RX_TCPHDR_LEN(htons(hdr_len))) |
+				V_IP_HDR_LEN(G_RX_IPHDR_LEN(htons(hdr_len))) |
+				V_ETH_HDR_LEN(G_RX_ETHHDR_LEN(htonl(l2info))));
+	req->vlan = vlantag;
+	req->len = len;
+	req->tos_stid = cpu_to_be32(PASS_OPEN_TID(stid) |
+				    PASS_OPEN_TOS(tos));
+	req->tcpopt.mss = htons(tmp_opt.mss_clamp);
+	if (tmp_opt.wscale_ok)
+		req->tcpopt.wsf = tmp_opt.snd_wscale;
+	req->tcpopt.tstamp = tmp_opt.saw_tstamp;
+	if (tmp_opt.sack_ok)
+		req->tcpopt.sack = 1;
+	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_PASS_ACCEPT_REQ, 0));
+	return;
+}
+
+static void send_fw_pass_open_req(struct c4iw_dev *dev, struct sk_buff *skb,
+				  __be32 laddr, __be16 lport,
+				  __be32 raddr, __be16 rport,
+				  u32 rcv_isn, u32 filter, u16 window,
+				  u32 rss_qid, u8 port_id)
+{
+	struct sk_buff *req_skb;
+	struct fw_ofld_connection_wr *req;
+	struct cpl_pass_accept_req *cpl = cplhdr(skb);
+
+	req_skb = alloc_skb(sizeof(struct fw_ofld_connection_wr), GFP_KERNEL);
+	req = (struct fw_ofld_connection_wr *)__skb_put(req_skb, sizeof(*req));
+	memset(req, 0, sizeof(*req));
+	req->op_compl = htonl(V_WR_OP(FW_OFLD_CONNECTION_WR) | FW_WR_COMPL(1));
+	req->len16_pkd = htonl(FW_WR_LEN16(DIV_ROUND_UP(sizeof(*req), 16)));
+	req->le.version_cpl = htonl(F_FW_OFLD_CONNECTION_WR_CPL);
+	req->le.filter = filter;
+	req->le.lport = lport;
+	req->le.pport = rport;
+	req->le.u.ipv4.lip = laddr;
+	req->le.u.ipv4.pip = raddr;
+	req->tcb.rcv_nxt = htonl(rcv_isn + 1);
+	req->tcb.rcv_adv = htons(window);
+	req->tcb.t_state_to_astid =
+		 htonl(V_FW_OFLD_CONNECTION_WR_T_STATE(TCP_SYN_RECV) |
+			V_FW_OFLD_CONNECTION_WR_RCV_SCALE(cpl->tcpopt.wsf) |
+			V_FW_OFLD_CONNECTION_WR_ASTID(
+			GET_PASS_OPEN_TID(ntohl(cpl->tos_stid))));
+
+	/*
+	 * We store the qid in opt2 which will be used by the firmware
+	 * to send us the wr response.
+	 */
+	req->tcb.opt2 = htonl(V_RSS_QUEUE(rss_qid));
+
+	/*
+	 * We initialize the MSS index in TCB to 0xF.
+	 * So that when driver sends cpl_pass_accept_rpl
+	 * TCB picks up the correct value. If this was 0
+	 * TP will ignore any value > 0 for MSS index.
+	 */
+	req->tcb.opt0 = cpu_to_be64(V_MSS_IDX(0xF));
+	req->cookie = cpu_to_be64((u64)skb);
+
+	set_wr_txq(req_skb, CPL_PRIORITY_CONTROL, port_id);
+	cxgb4_ofld_send(dev->rdev.lldi.ports[0], req_skb);
+}
+
+/*
+ * Handler for CPL_RX_PKT message. Need to handle cpl_rx_pkt
+ * messages when a filter is being used instead of server to
+ * redirect a syn packet. When packets hit filter they are redirected
+ * to the offload queue and driver tries to establish the connection
+ * using firmware work request.
+ */
+static int rx_pkt(struct c4iw_dev *dev, struct sk_buff *skb)
+{
+	int stid;
+	unsigned int filter;
+	struct ethhdr *eh = NULL;
+	struct vlan_ethhdr *vlan_eh = NULL;
+	struct iphdr *iph;
+	struct tcphdr *tcph;
+	struct rss_header *rss = (void *)skb->data;
+	struct cpl_rx_pkt *cpl = (void *)skb->data;
+	struct cpl_pass_accept_req *req = (void *)(rss + 1);
+	struct l2t_entry *e;
+	struct dst_entry *dst;
+	struct rtable *rt;
+	struct c4iw_ep *lep;
+	u16 window;
+	struct port_info *pi;
+	struct net_device *pdev;
+	u16 rss_qid;
+	int step;
+	u32 tx_chan;
+	struct neighbour *neigh;
+
+	/* Drop all non-SYN packets */
+	if (!(cpl->l2info & cpu_to_be32(F_RXF_SYN)))
+		goto reject;
+
+	/*
+	 * Drop all packets which did not hit the filter.
+	 * Unlikely to happen.
+	 */
+	if (!(rss->filter_hit && rss->filter_tid))
+		goto reject;
+
+	/*
+	 * Calculate the server tid from filter hit index from cpl_rx_pkt.
+	 */
+	stid = cpu_to_be32(rss->hash_val) - dev->rdev.lldi.tids->sftid_base
+					  + dev->rdev.lldi.tids->nstids;
+
+	lep = (struct c4iw_ep *)lookup_stid(dev->rdev.lldi.tids, stid);
+	if (!lep) {
+		PDBG("%s connect request on invalid stid %d\n", __func__, stid);
+		goto reject;
+	}
+
+	if (G_RX_ETHHDR_LEN(ntohl(cpl->l2info)) == ETH_HLEN) {
+		eh = (struct ethhdr *)(req + 1);
+		iph = (struct iphdr *)(eh + 1);
+	} else {
+		vlan_eh = (struct vlan_ethhdr *)(req + 1);
+		iph = (struct iphdr *)(vlan_eh + 1);
+		skb->vlan_tci = ntohs(cpl->vlan);
+	}
+
+	if (iph->version != 0x4)
+		goto reject;
+
+	tcph = (struct tcphdr *)(iph + 1);
+	skb_set_network_header(skb, (void *)iph - (void *)rss);
+	skb_set_transport_header(skb, (void *)tcph - (void *)rss);
+	skb_get(skb);
+
+	PDBG("%s lip 0x%x lport %u pip 0x%x pport %u tos %d\n", __func__,
+	     ntohl(iph->daddr), ntohs(tcph->dest), ntohl(iph->saddr),
+	     ntohs(tcph->source), iph->tos);
+
+	rt = find_route(dev, iph->daddr, iph->saddr, tcph->dest, tcph->source,
+			iph->tos);
+	if (!rt) {
+		pr_err("%s - failed to find dst entry!\n",
+		       __func__);
+		goto reject;
+	}
+	dst = &rt->dst;
+	neigh = dst_neigh_lookup_skb(dst, skb);
+
+	if (neigh->dev->flags & IFF_LOOPBACK) {
+		pdev = ip_dev_find(&init_net, iph->daddr);
+		e = cxgb4_l2t_get(dev->rdev.lldi.l2t, neigh,
+				    pdev, 0);
+		pi = (struct port_info *)netdev_priv(pdev);
+		tx_chan = cxgb4_port_chan(pdev);
+		dev_put(pdev);
+	} else {
+		e = cxgb4_l2t_get(dev->rdev.lldi.l2t, neigh,
+					neigh->dev, 0);
+		pi = (struct port_info *)netdev_priv(neigh->dev);
+		tx_chan = cxgb4_port_chan(neigh->dev);
+	}
+	if (!e) {
+		pr_err("%s - failed to allocate l2t entry!\n",
+		       __func__);
+		goto free_dst;
+	}
+
+	step = dev->rdev.lldi.nrxq / dev->rdev.lldi.nchan;
+	rss_qid = dev->rdev.lldi.rxq_ids[pi->port_id * step];
+	window = htons(tcph->window);
+
+	/* Calcuate filter portion for LE region. */
+	filter = cpu_to_be32(select_ntuple(dev, dst, e));
+
+	/*
+	 * Synthesize the cpl_pass_accept_req. We have everything except the
+	 * TID. Once firmware sends a reply with TID we update the TID field
+	 * in cpl and pass it through the regular cpl_pass_accept_req path.
+	 */
+	build_cpl_pass_accept_req(skb, stid, iph->tos);
+	send_fw_pass_open_req(dev, skb, iph->daddr, tcph->dest, iph->saddr,
+			      tcph->source, ntohl(tcph->seq), filter, window,
+			      rss_qid, pi->port_id);
+	cxgb4_l2t_release(e);
+free_dst:
+	dst_release(dst);
+reject:
 	return 0;
 }
 
@@ -2647,7 +2977,8 @@ static c4iw_handler_func work_handlers[NUM_CPL_CMDS] = {
 	[CPL_CLOSE_CON_RPL] = close_con_rpl,
 	[CPL_RDMA_TERMINATE] = terminate,
 	[CPL_FW4_ACK] = fw4_ack,
-	[CPL_FW6_MSG] = async_event
+	[CPL_FW6_MSG] = deferred_fw6_msg,
+	[CPL_RX_PKT] = rx_pkt
 };
 
 static void process_timeout(struct c4iw_ep *ep)
@@ -2774,9 +3105,6 @@ static int fw6_msg(struct c4iw_dev *dev, struct sk_buff *skb)
 	struct cpl_fw6_msg *rpl = cplhdr(skb);
 	struct c4iw_wr_wait *wr_waitp;
 	int ret;
-	u8 opcode;
-	struct cpl_fw6_msg_ofld_connection_wr_rpl *req;
-	struct c4iw_ep *ep;
 
 	PDBG("%s type %u\n", __func__, rpl->type);
 
@@ -2790,23 +3118,8 @@ static int fw6_msg(struct c4iw_dev *dev, struct sk_buff *skb)
 		kfree_skb(skb);
 		break;
 	case FW6_TYPE_CQE:
-		sched(dev, skb);
-		break;
 	case FW6_TYPE_OFLD_CONNECTION_WR_RPL:
-		opcode = *(const u8 *)rpl->data;
-		if (opcode == FW_OFLD_CONNECTION_WR) {
-			req =
-			(struct cpl_fw6_msg_ofld_connection_wr_rpl *)rpl->data;
-			if (req->t_state == TCP_SYN_SENT
-			    && (req->retval == FW_ENOMEM
-				|| req->retval == FW_EADDRINUSE)) {
-				ep = (struct c4iw_ep *)
-				     lookup_atid(dev->rdev.lldi.tids,
-						 req->tid);
-				c4iw_l2t_send(&dev->rdev, skb, ep->l2t);
-				return 0;
-			}
-		}
+		sched(dev, skb);
 		break;
 	default:
 		printk(KERN_ERR MOD "%s unexpected fw6 msg type %u\n", __func__,
@@ -2868,7 +3181,8 @@ c4iw_handler_func c4iw_handlers[NUM_CPL_CMDS] = {
 	[CPL_RDMA_TERMINATE] = sched,
 	[CPL_FW4_ACK] = sched,
 	[CPL_SET_TCB_RPL] = set_tcb_rpl,
-	[CPL_FW6_MSG] = fw6_msg
+	[CPL_FW6_MSG] = fw6_msg,
+	[CPL_RX_PKT] = sched
 };
 
 int __init c4iw_cm_init(void)
diff --git a/drivers/infiniband/hw/cxgb4/device.c b/drivers/infiniband/hw/cxgb4/device.c
index cb4ecd783700..6b5b3d15e48d 100644
--- a/drivers/infiniband/hw/cxgb4/device.c
+++ b/drivers/infiniband/hw/cxgb4/device.c
@@ -279,6 +279,7 @@ static int stats_show(struct seq_file *seq, void *v)
 	seq_printf(seq, " DB State: %s Transitions %llu\n",
 		   db_state_str[dev->db_state],
 		   dev->rdev.stats.db_state_transitions);
+	seq_printf(seq, "TCAM_FULL: %10llu\n", dev->rdev.stats.tcam_full);
 	return 0;
 }
 
@@ -577,14 +578,76 @@ out:
 	return ctx;
 }
 
+static inline struct sk_buff *copy_gl_to_skb_pkt(const struct pkt_gl *gl,
+						 const __be64 *rsp,
+						 u32 pktshift)
+{
+	struct sk_buff *skb;
+
+	/*
+	 * Allocate space for cpl_pass_accept_req which will be synthesized by
+	 * driver. Once the driver synthesizes the request the skb will go
+	 * through the regular cpl_pass_accept_req processing.
+	 * The math here assumes sizeof cpl_pass_accept_req >= sizeof
+	 * cpl_rx_pkt.
+	 */
+	skb = alloc_skb(gl->tot_len + sizeof(struct cpl_pass_accept_req) +
+			sizeof(struct rss_header) - pktshift, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return NULL;
+
+	 __skb_put(skb, gl->tot_len + sizeof(struct cpl_pass_accept_req) +
+		   sizeof(struct rss_header) - pktshift);
+
+	/*
+	 * This skb will contain:
+	 *   rss_header from the rspq descriptor (1 flit)
+	 *   cpl_rx_pkt struct from the rspq descriptor (2 flits)
+	 *   space for the difference between the size of an
+	 *      rx_pkt and pass_accept_req cpl (1 flit)
+	 *   the packet data from the gl
+	 */
+	skb_copy_to_linear_data(skb, rsp, sizeof(struct cpl_pass_accept_req) +
+				sizeof(struct rss_header));
+	skb_copy_to_linear_data_offset(skb, sizeof(struct rss_header) +
+				       sizeof(struct cpl_pass_accept_req),
+				       gl->va + pktshift,
+				       gl->tot_len - pktshift);
+	return skb;
+}
+
+static inline int recv_rx_pkt(struct c4iw_dev *dev, const struct pkt_gl *gl,
+			   const __be64 *rsp)
+{
+	unsigned int opcode = *(u8 *)rsp;
+	struct sk_buff *skb;
+
+	if (opcode != CPL_RX_PKT)
+		goto out;
+
+	skb = copy_gl_to_skb_pkt(gl , rsp, dev->rdev.lldi.sge_pktshift);
+	if (skb == NULL)
+		goto out;
+
+	if (c4iw_handlers[opcode] == NULL) {
+		pr_info("%s no handler opcode 0x%x...\n", __func__,
+		       opcode);
+		kfree_skb(skb);
+		goto out;
+	}
+	c4iw_handlers[opcode](dev, skb);
+	return 1;
+out:
+	return 0;
+}
+
 static int c4iw_uld_rx_handler(void *handle, const __be64 *rsp,
 			const struct pkt_gl *gl)
 {
 	struct uld_ctx *ctx = handle;
 	struct c4iw_dev *dev = ctx->dev;
 	struct sk_buff *skb;
-	const struct cpl_act_establish *rpl;
-	unsigned int opcode;
+	u8 opcode;
 
 	if (gl == NULL) {
 		/* omit RSS and rsp_ctrl at end of descriptor */
@@ -601,19 +664,29 @@ static int c4iw_uld_rx_handler(void *handle, const __be64 *rsp,
 		u32 qid = be32_to_cpu(rc->pldbuflen_qid);
 		c4iw_ev_handler(dev, qid);
 		return 0;
+	} else if (unlikely(*(u8 *)rsp != *(u8 *)gl->va)) {
+		if (recv_rx_pkt(dev, gl, rsp))
+			return 0;
+
+		pr_info("%s: unexpected FL contents at %p, " \
+		       "RSS %#llx, FL %#llx, len %u\n",
+		       pci_name(ctx->lldi.pdev), gl->va,
+		       (unsigned long long)be64_to_cpu(*rsp),
+		       (unsigned long long)be64_to_cpu(*(u64 *)gl->va),
+		       gl->tot_len);
+
+		return 0;
 	} else {
 		skb = cxgb4_pktgl_to_skb(gl, 128, 128);
 		if (unlikely(!skb))
 			goto nomem;
 	}
 
-	rpl = cplhdr(skb);
-	opcode = rpl->ot.opcode;
-
+	opcode = *(u8 *)rsp;
 	if (c4iw_handlers[opcode])
 		c4iw_handlers[opcode](dev, skb);
 	else
-		printk(KERN_INFO "%s no handler opcode 0x%x...\n", __func__,
+		pr_info("%s no handler opcode 0x%x...\n", __func__,
 		       opcode);
 
 	return 0;