RDMA/nes: Allocate work item for disconnect event handling

The code currently has a work structure in the QP.  This requires a
lock and a pending flag to ensure there is never more than one request
active.  When two events happen quickly (such as FIN and LLP CLOSE),
it causes unnecessary timeouts since the second one is dropped.

This fix allocates memory for the work request so the second one can
be queued.  A lock is removed since it is no longer needed.
Signed-off-by: Don Wood <donald.e.wood@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/nes/nes_cm.c

@@ -2450,20 +2450,16 @@ static int nes_cm_init_tsa_conn(struct nes_qp *nesqp, struct nes_cm_node *cm_nod
  */
 int nes_cm_disconn(struct nes_qp *nesqp)
 {
-	unsigned long flags;
+	struct disconn_work *work;
 
-	spin_lock_irqsave(&nesqp->lock, flags);
-	if (nesqp->disconn_pending == 0) {
-		nesqp->disconn_pending++;
-		spin_unlock_irqrestore(&nesqp->lock, flags);
-		nes_add_ref(&nesqp->ibqp);
-		/* init our disconnect work element, to */
-		INIT_WORK(&nesqp->disconn_work, nes_disconnect_worker);
-
-		queue_work(g_cm_core->disconn_wq, &nesqp->disconn_work);
-	} else
-		spin_unlock_irqrestore(&nesqp->lock, flags);
+	work = kzalloc(sizeof *work, GFP_ATOMIC);
+	if (!work)
+		return -ENOMEM; /* Timer will clean up */
 
+	nes_add_ref(&nesqp->ibqp);
+	work->nesqp = nesqp;
+	INIT_WORK(&work->work, nes_disconnect_worker);
+	queue_work(g_cm_core->disconn_wq, &work->work);
 	return 0;
 }
 
@@ -2473,8 +2469,10 @@ int nes_cm_disconn(struct nes_qp *nesqp)
  */
 static void nes_disconnect_worker(struct work_struct *work)
 {
-	struct nes_qp *nesqp = container_of(work, struct nes_qp, disconn_work);
+	struct disconn_work *dwork = container_of(work, struct disconn_work, work);
+	struct nes_qp *nesqp = dwork->nesqp;
 
+	kfree(dwork);
 	nes_debug(NES_DBG_CM, "processing AEQE id 0x%04X for QP%u.\n",
 			nesqp->last_aeq, nesqp->hwqp.qp_id);
 	nes_cm_disconn_true(nesqp);
@@ -2557,7 +2555,6 @@ static int nes_cm_disconn_true(struct nes_qp *nesqp)
 			spin_lock_irqsave(&nesqp->lock, flags);
 		}
 
-		nesqp->disconn_pending = 0;
 		/* There might have been another AE while the lock was released */
 		original_hw_tcp_state = nesqp->hw_tcp_state;
 		original_ibqp_state   = nesqp->ibqp_state;
@@ -2610,7 +2607,6 @@ static int nes_cm_disconn_true(struct nes_qp *nesqp)
 			}
 		}
 	} else {
-		nesqp->disconn_pending = 0;
 		spin_unlock_irqrestore(&nesqp->lock, flags);
 	}
 

drivers/infiniband/hw/nes/nes_verbs.h

@@ -119,6 +119,11 @@ struct nes_wq {
 	spinlock_t lock;
 };
 
+struct disconn_work {
+	struct work_struct    work;
+	struct nes_qp         *nesqp;
+};
+
 struct iw_cm_id;
 struct ietf_mpa_frame;
 
@@ -127,7 +132,6 @@ struct nes_qp {
 	void                  *allocated_buffer;
 	struct iw_cm_id       *cm_id;
 	struct workqueue_struct *wq;
-	struct work_struct    disconn_work;
 	struct nes_cq         *nesscq;
 	struct nes_cq         *nesrcq;
 	struct nes_pd         *nespd;
@@ -165,7 +169,6 @@ struct nes_qp {
 	u8                    hw_iwarp_state;
 	u8                    flush_issued;
 	u8                    hw_tcp_state;
-	u8                    disconn_pending;
 	u8                    destroyed;
 };
 #endif			/* NES_VERBS_H */