RDMA/cxgb4: Lock around accept/reject downcalls

There is a race between ULP threads doing an accept/reject, and the
ingress processing thread handling close/abort for the same connection.
The accept/reject path needs to hold the lock to serialize these paths.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>

[ Fold in locking fix found by Dan Carpenter <dan.carpenter@oracle.com>.
  - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 21 insertions, 10 deletions

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index a1bc41d04620..6836d114d75a 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -760,7 +760,7 @@ static void send_mpa_req(struct c4iw_ep *ep, struct sk_buff *skb,
         ep->mpa_skb = skb;
         c4iw_l2t_send(&ep->com.dev->rdev, skb, ep->l2t);
         start_ep_timer(ep);
-        state_set(&ep->com, MPA_REQ_SENT);
+        __state_set(&ep->com, MPA_REQ_SENT);
         ep->mpa_attr.initiator = 1;
         ep->snd_seq += mpalen;
         return;
@@ -926,7 +926,7 @@ static int send_mpa_reply(struct c4iw_ep *ep, const void *pdata, u8 plen)
         skb_get(skb);
         t4_set_arp_err_handler(skb, NULL, arp_failure_discard);
         ep->mpa_skb = skb;
-        state_set(&ep->com, MPA_REP_SENT);
+        __state_set(&ep->com, MPA_REP_SENT);
         ep->snd_seq += mpalen;
         return c4iw_l2t_send(&ep->com.dev->rdev, skb, ep->l2t);
 }
@@ -944,6 +944,7 @@ static int act_establish(struct c4iw_dev *dev, struct sk_buff *skb)
         PDBG("%s ep %p tid %u snd_isn %u rcv_isn %u\n", __func__, ep, tid,
              be32_to_cpu(req->snd_isn), be32_to_cpu(req->rcv_isn));
 
+        mutex_lock(&ep->com.mutex);
         dst_confirm(ep->dst);
 
         /* setup the hwtid for this connection */
@@ -967,7 +968,7 @@ static int act_establish(struct c4iw_dev *dev, struct sk_buff *skb)
                 send_mpa_req(ep, skb, 1);
         else
                 send_mpa_req(ep, skb, mpa_rev);
-
+        mutex_unlock(&ep->com.mutex);
         return 0;
 }
 
@@ -2511,22 +2512,28 @@ static int fw4_ack(struct c4iw_dev *dev, struct sk_buff *skb)
 
 int c4iw_reject_cr(struct iw_cm_id *cm_id, const void *pdata, u8 pdata_len)
 {
-        int err;
+        int err = 0;
+        int disconnect = 0;
         struct c4iw_ep *ep = to_ep(cm_id);
         PDBG("%s ep %p tid %u\n", __func__, ep, ep->hwtid);
 
-        if (state_read(&ep->com) == DEAD) {
+        mutex_lock(&ep->com.mutex);
+        if (ep->com.state == DEAD) {
+                mutex_unlock(&ep->com.mutex);
                 c4iw_put_ep(&ep->com);
                 return -ECONNRESET;
         }
         set_bit(ULP_REJECT, &ep->com.history);
-        BUG_ON(state_read(&ep->com) != MPA_REQ_RCVD);
+        BUG_ON(ep->com.state != MPA_REQ_RCVD);
         if (mpa_rev == 0)
                 abort_connection(ep, NULL, GFP_KERNEL);
         else {
                 err = send_mpa_reject(ep, pdata, pdata_len);
-                err = c4iw_ep_disconnect(ep, 0, GFP_KERNEL);
+                disconnect = 1;
         }
+        mutex_unlock(&ep->com.mutex);
+        if (disconnect)
+                err = c4iw_ep_disconnect(ep, 0, GFP_KERNEL);
         c4iw_put_ep(&ep->com);
         return 0;
 }
@@ -2541,12 +2548,14 @@ int c4iw_accept_cr(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
         struct c4iw_qp *qp = get_qhp(h, conn_param->qpn);
 
         PDBG("%s ep %p tid %u\n", __func__, ep, ep->hwtid);
-        if (state_read(&ep->com) == DEAD) {
+
+        mutex_lock(&ep->com.mutex);
+        if (ep->com.state == DEAD) {
                 err = -ECONNRESET;
                 goto err;
         }
 
-        BUG_ON(state_read(&ep->com) != MPA_REQ_RCVD);
+        BUG_ON(ep->com.state != MPA_REQ_RCVD);
         BUG_ON(!qp);
 
         set_bit(ULP_ACCEPT, &ep->com.history);
@@ -2615,14 +2624,16 @@ int c4iw_accept_cr(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param)
         if (err)
                 goto err1;
 
-        state_set(&ep->com, FPDU_MODE);
+        __state_set(&ep->com, FPDU_MODE);
         established_upcall(ep);
+        mutex_unlock(&ep->com.mutex);
         c4iw_put_ep(&ep->com);
         return 0;
 err1:
         ep->com.cm_id = NULL;
         cm_id->rem_ref(cm_id);
 err:
+        mutex_unlock(&ep->com.mutex);
         c4iw_put_ep(&ep->com);
         return err;
 }