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>

diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index 257d994..c259ddc 100644 (file)
--- 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 282a9cb..25e2493 100644 (file)
--- 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. */