RDMA/nes: Avoid race between MPA request and reset event to rdma_cm

In passive open, after indicating MPA request to rdma_cm, an incoming
RST would fire a reset event to rdma_cm causing it to crash, since the
current state is not connected.  The solution is to wait for
nes_accept() or nes_reject() before firing the reset event.  If
nes_accept() or nes_reject() is already done, then the reset event
will be fired when RST is processed.

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>

2 files changed, 49 insertions, 6 deletions

diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index 257d994ec7b5..c259ddc8dd88 100644
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -1360,6 +1360,7 @@ static void handle_rst_pkt(struct nes_cm_node *cm_node, struct sk_buff *skb,
 {
 
         int     reset = 0;      /* whether to send reset in case of err.. */
+        int     passive_state;
         atomic_inc(&cm_resets_recvd);
         nes_debug(NES_DBG_CM, "Received Reset, cm_node = %p, state = %u."
                         " refcnt=%d\n", cm_node, cm_node->state,
@@ -1373,7 +1374,14 @@ static void handle_rst_pkt(struct nes_cm_node *cm_node, struct sk_buff *skb,
                         cm_node->listener, cm_node->state);
                 active_open_err(cm_node, skb, reset);
                 break;
-        /* For PASSIVE open states, remove the cm_node event */
+        case NES_CM_STATE_MPAREQ_RCVD:
+                passive_state = atomic_add_return(1, &cm_node->passive_state);
+                if (passive_state ==  NES_SEND_RESET_EVENT)
+                        create_event(cm_node, NES_CM_EVENT_RESET);
+                cleanup_retrans_entry(cm_node);
+                cm_node->state = NES_CM_STATE_CLOSED;
+                dev_kfree_skb_any(skb);
+                break;
         case NES_CM_STATE_ESTABLISHED:
         case NES_CM_STATE_SYN_RCVD:
         case NES_CM_STATE_LISTENING:
@@ -1381,7 +1389,14 @@ static void handle_rst_pkt(struct nes_cm_node *cm_node, struct sk_buff *skb,
                 passive_open_err(cm_node, skb, reset);
                 break;
         case NES_CM_STATE_TSA:
+                active_open_err(cm_node, skb, reset);
+                break;
+        case NES_CM_STATE_CLOSED:
+                cleanup_retrans_entry(cm_node);
+                drop_packet(skb);
+                break;
         default:
+                drop_packet(skb);
                 break;
         }
 }
@@ -1410,6 +1425,9 @@ static void handle_rcv_mpa(struct nes_cm_node *cm_node, struct sk_buff *skb,
                 dev_kfree_skb_any(skb);
                 if (type == NES_CM_EVENT_CONNECTED)
                         cm_node->state = NES_CM_STATE_TSA;
+                else
+                        atomic_set(&cm_node->passive_state,
+                                        NES_PASSIVE_STATE_INDICATED);
                 create_event(cm_node, type);
 
         }
@@ -1986,6 +2004,7 @@ static int mini_cm_reject(struct nes_cm_core *cm_core,
         struct ietf_mpa_frame *mpa_frame, struct nes_cm_node *cm_node)
 {
         int ret = 0;
+        int passive_state;
 
         nes_debug(NES_DBG_CM, "%s cm_node=%p type=%d state=%d\n",
                 __func__, cm_node, cm_node->tcp_cntxt.client, cm_node->state);
@@ -1993,9 +2012,13 @@ static int mini_cm_reject(struct nes_cm_core *cm_core,
         if (cm_node->tcp_cntxt.client)
                 return ret;
         cleanup_retrans_entry(cm_node);
-        cm_node->state = NES_CM_STATE_CLOSED;
 
-        ret = send_reset(cm_node, NULL);
+        passive_state = atomic_add_return(1, &cm_node->passive_state);
+        cm_node->state = NES_CM_STATE_CLOSED;
+        if (passive_state == NES_SEND_RESET_EVENT)
+                rem_ref_cm_node(cm_core, cm_node);
+        else
+                ret = send_reset(cm_node, NULL);
         return ret;
 }
 
@@ -2413,7 +2436,6 @@ static int nes_cm_disconn_true(struct nes_qp *nesqp)
                         atomic_inc(&cm_disconnects);
                         cm_event.event = IW_CM_EVENT_DISCONNECT;
                         if (last_ae == NES_AEQE_AEID_LLP_CONNECTION_RESET) {
-                                issued_disconnect_reset = 1;
                                 cm_event.status = IW_CM_EVENT_STATUS_RESET;
                                 nes_debug(NES_DBG_CM, "Generating a CM "
                                         "Disconnect Event (status reset) for "
@@ -2563,6 +2585,7 @@ int nes_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
         struct nes_v4_quad nes_quad;
         u32 crc_value;
         int ret;
+        int passive_state;
 
         ibqp = nes_get_qp(cm_id->device, conn_param->qpn);
         if (!ibqp)
@@ -2730,8 +2753,6 @@ int nes_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
                         conn_param->private_data_len +
                         sizeof(struct ietf_mpa_frame));
 
-        attr.qp_state = IB_QPS_RTS;
-        nes_modify_qp(&nesqp->ibqp, &attr, IB_QP_STATE, NULL);
 
         /* notify OF layer that accept event was successfull */
         cm_id->add_ref(cm_id);
@@ -2744,6 +2765,8 @@ int nes_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
         cm_event.private_data = NULL;
         cm_event.private_data_len = 0;
         ret = cm_id->event_handler(cm_id, &cm_event);
+        attr.qp_state = IB_QPS_RTS;
+        nes_modify_qp(&nesqp->ibqp, &attr, IB_QP_STATE, NULL);
         if (cm_node->loopbackpartner) {
                 cm_node->loopbackpartner->mpa_frame_size =
                         nesqp->private_data_len;
@@ -2756,6 +2779,9 @@ int nes_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
                 printk(KERN_ERR "%s[%u] OFA CM event_handler returned, "
                         "ret=%d\n", __func__, __LINE__, ret);
 
+        passive_state = atomic_add_return(1, &cm_node->passive_state);
+        if (passive_state == NES_SEND_RESET_EVENT)
+                create_event(cm_node, NES_CM_EVENT_RESET);
         return 0;
 }
 
@@ -3238,6 +3264,18 @@ static void cm_event_reset(struct nes_cm_event *event)
         cm_event.private_data_len = 0;
 
         ret = cm_id->event_handler(cm_id, &cm_event);
+        cm_id->add_ref(cm_id);
+        atomic_inc(&cm_closes);
+        cm_event.event = IW_CM_EVENT_CLOSE;
+        cm_event.status = IW_CM_EVENT_STATUS_OK;
+        cm_event.provider_data = cm_id->provider_data;
+        cm_event.local_addr = cm_id->local_addr;
+        cm_event.remote_addr = cm_id->remote_addr;
+        cm_event.private_data = NULL;
+        cm_event.private_data_len = 0;
+        nes_debug(NES_DBG_CM, "NODE %p Generating CLOSE\n", event->cm_node);
+        ret = cm_id->event_handler(cm_id, &cm_event);
+
         nes_debug(NES_DBG_CM, "OFA CM event_handler returned, ret=%d\n", ret);
 
 
diff --git a/drivers/infiniband/hw/nes/nes_cm.h b/drivers/infiniband/hw/nes/nes_cm.h
index 282a9cbe508f..25e2493abc6a 100644
--- a/drivers/infiniband/hw/nes/nes_cm.h
+++ b/drivers/infiniband/hw/nes/nes_cm.h
@@ -76,6 +76,10 @@ enum nes_timer_type {
         NES_TIMER_TYPE_CLOSE,
 };
 
+#define NES_PASSIVE_STATE_INDICATED     0
+#define NES_DO_NOT_SEND_RESET_EVENT     1
+#define NES_SEND_RESET_EVENT            2
+
 #define MAX_NES_IFS 4
 
 #define SET_ACK 1
@@ -295,6 +299,7 @@ struct nes_cm_node {
         struct list_head        timer_entry;
         struct list_head        reset_entry;
         struct nes_qp           *nesqp;
+        atomic_t                passive_state;
 };
 
 /* structure for client or CM to fill when making CM api calls. */