[openib-general] hack around IWCM double-close problem

[Pete Wyckoff]

In some cases using Ammasso devices, a CONNECTION_LOST message may
come from c2_ae_event while something else is in the middle of
c2_destroy_qp.  If that happens, a BUG_ON triggers in
cm_close_handler as the QP goes to IDLE after the first of the two
calls.  Perhaps this is a problem with the Ammasso driver, but this
little hack-around hid it for me.

Signed-off-by: Pete Wyckoff <pw at osc.edu>

Index: linux-kernel/infiniband/core/iwcm.c
===================================================================
--- linux-kernel/infiniband/core/iwcm.c	(revision 8688)
+++ linux-kernel/infiniband/core/iwcm.c	(working copy)
@@ -673,6 +673,12 @@
 	case IW_CM_STATE_DESTROYING:
 		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 		break;
+	case IW_CM_STATE_IDLE:
+		/* protect against double-close from concurrent c2_destroy_qp
+		 * and c2_ae_event CONNECTION_LOST */
+		printk(KERN_INFO "%s: in IDLE state, ignoring\n", __func__);
+		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+		break;
 	default:
 		BUG_ON(1);
 	}