RDMA/cxgb4: Don't change QP state outside EP lock

Concurrent ingress CLOSE and ULP ABORT operations causes a crash due
to a race condition where the close path releases the EP lock and then
tries to move the QP state to CLOSED.  This must be done inside the EP
lock to avoid the race.
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/cxgb4/cm.c

@@ -1466,7 +1466,7 @@ static int peer_close(struct c4iw_dev *dev, struct sk_buff *skb)
 	struct c4iw_qp_attributes attrs;
 	int disconnect = 1;
 	int release = 0;
-	int closing = 0;
+	int abort = 0;
 	struct tid_info *t = dev->rdev.lldi.tids;
 	unsigned int tid = GET_TID(hdr);
 
@@ -1507,8 +1507,11 @@ static int peer_close(struct c4iw_dev *dev, struct sk_buff *skb)
 	case FPDU_MODE:
 		start_ep_timer(ep);
 		__state_set(&ep->com, CLOSING);
-		closing = 1;
+		attrs.next_state = C4IW_QP_STATE_CLOSING;
+		abort = c4iw_modify_qp(ep->com.qp->rhp, ep->com.qp,
+				       C4IW_QP_ATTR_NEXT_STATE, &attrs, 1);
 		peer_close_upcall(ep);
+		disconnect = 1;
 		break;
 	case ABORTING:
 		disconnect = 0;
@@ -1536,11 +1539,6 @@ static int peer_close(struct c4iw_dev *dev, struct sk_buff *skb)
 		BUG_ON(1);
 	}
 	mutex_unlock(&ep->com.mutex);
-	if (closing) {
-		attrs.next_state = C4IW_QP_STATE_CLOSING;
-		c4iw_modify_qp(ep->com.qp->rhp, ep->com.qp,
-			       C4IW_QP_ATTR_NEXT_STATE, &attrs, 1);
-	}
 	if (disconnect)
 		c4iw_ep_disconnect(ep, 0, GFP_KERNEL);
 	if (release)
@@ -1710,14 +1708,14 @@ static int terminate(struct c4iw_dev *dev, struct sk_buff *skb)
 	ep = lookup_tid(t, tid);
 	BUG_ON(!ep);
 
-	if (ep->com.qp) {
+	if (ep && ep->com.qp) {
 		printk(KERN_WARNING MOD "TERM received tid %u qpid %u\n", tid,
 		       ep->com.qp->wq.sq.qid);
 		attrs.next_state = C4IW_QP_STATE_TERMINATE;
 		c4iw_modify_qp(ep->com.qp->rhp, ep->com.qp,
 			       C4IW_QP_ATTR_NEXT_STATE, &attrs, 1);
 	} else
-		printk(KERN_WARNING MOD "TERM received tid %u no qp\n", tid);
+		printk(KERN_WARNING MOD "TERM received tid %u no ep/qp\n", tid);
 
 	return 0;
 }

drivers/infiniband/hw/cxgb4/iw_cxgb4.h

@@ -161,7 +161,7 @@ static inline int c4iw_wait_for_reply(struct c4iw_rdev *rdev,
 		}
 	} while (!wr_waitp->done);
 	if (wr_waitp->ret)
-		printk(KERN_WARNING MOD "%s: FW reply %d tid %u qpid %u\n",
+		PDBG("%s: FW reply %d tid %u qpid %u\n",
 		     pci_name(rdev->lldi.pdev), wr_waitp->ret, hwtid, qpid);
 	return wr_waitp->ret;
 }

drivers/infiniband/hw/cxgb4/qp.c

@@ -1210,7 +1210,6 @@ int c4iw_modify_qp(struct c4iw_dev *rhp, struct c4iw_qp *qhp,
 			if (ret) {
 				if (internal)
 					c4iw_get_ep(&qhp->ep->com);
-				disconnect = abort = 1;
 				goto err;
 			}
 			break;