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	IB/cm: Randomize starting comm ID
Randomize the starting local comm ID to avoid getting a rejected connection due to a stale connection after a system reboot or reloading of the ib_cm. Signed-off-by: Sean Hefty <sean.hefty@intel.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
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					 1 changed files with 16 additions and 8 deletions
				
			
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			@ -1,5 +1,5 @@
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/*
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 * Copyright (c) 2004, 2005 Intel Corporation.  All rights reserved.
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 * Copyright (c) 2004-2006 Intel Corporation.  All rights reserved.
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 * Copyright (c) 2004 Topspin Corporation.  All rights reserved.
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 * Copyright (c) 2004, 2005 Voltaire Corporation.  All rights reserved.
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 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
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			@ -41,6 +41,7 @@
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#include <linux/idr.h>
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#include <linux/interrupt.h>
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#include <linux/pci.h>
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#include <linux/random.h>
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#include <linux/rbtree.h>
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#include <linux/spinlock.h>
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#include <linux/workqueue.h>
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			@ -73,6 +74,7 @@ static struct ib_cm {
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	struct rb_root remote_id_table;
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	struct rb_root remote_sidr_table;
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	struct idr local_id_table;
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	__be32 random_id_operand;
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	struct workqueue_struct *wq;
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} cm;
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			@ -299,15 +301,17 @@ static int cm_init_av_by_path(struct ib_sa_path_rec *path, struct cm_av *av)
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static int cm_alloc_id(struct cm_id_private *cm_id_priv)
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{
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	unsigned long flags;
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	int ret;
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	int ret, id;
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	static int next_id;
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	do {
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		spin_lock_irqsave(&cm.lock, flags);
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		ret = idr_get_new_above(&cm.local_id_table, cm_id_priv, next_id++,
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					(__force int *) &cm_id_priv->id.local_id);
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		ret = idr_get_new_above(&cm.local_id_table, cm_id_priv,
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					next_id++, &id);
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		spin_unlock_irqrestore(&cm.lock, flags);
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	} while( (ret == -EAGAIN) && idr_pre_get(&cm.local_id_table, GFP_KERNEL) );
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	cm_id_priv->id.local_id = (__force __be32) (id ^ cm.random_id_operand);
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	return ret;
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}
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			@ -316,7 +320,8 @@ static void cm_free_id(__be32 local_id)
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	unsigned long flags;
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	spin_lock_irqsave(&cm.lock, flags);
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	idr_remove(&cm.local_id_table, (__force int) local_id);
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	idr_remove(&cm.local_id_table,
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		   (__force int) (local_id ^ cm.random_id_operand));
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	spin_unlock_irqrestore(&cm.lock, flags);
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}
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			@ -324,7 +329,8 @@ static struct cm_id_private * cm_get_id(__be32 local_id, __be32 remote_id)
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{
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	struct cm_id_private *cm_id_priv;
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	cm_id_priv = idr_find(&cm.local_id_table, (__force int) local_id);
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	cm_id_priv = idr_find(&cm.local_id_table,
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			      (__force int) (local_id ^ cm.random_id_operand));
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	if (cm_id_priv) {
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		if (cm_id_priv->id.remote_id == remote_id)
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			atomic_inc(&cm_id_priv->refcount);
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			@ -2082,8 +2088,9 @@ static struct cm_id_private * cm_acquire_rejected_id(struct cm_rej_msg *rej_msg)
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			spin_unlock_irqrestore(&cm.lock, flags);
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			return NULL;
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		}
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		cm_id_priv = idr_find(&cm.local_id_table,
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				      (__force int) timewait_info->work.local_id);
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		cm_id_priv = idr_find(&cm.local_id_table, (__force int)
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				      (timewait_info->work.local_id ^
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				       cm.random_id_operand));
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		if (cm_id_priv) {
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			if (cm_id_priv->id.remote_id == remote_id)
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				atomic_inc(&cm_id_priv->refcount);
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			@ -3360,6 +3367,7 @@ static int __init ib_cm_init(void)
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	cm.remote_qp_table = RB_ROOT;
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	cm.remote_sidr_table = RB_ROOT;
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	idr_init(&cm.local_id_table);
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	get_random_bytes(&cm.random_id_operand, sizeof cm.random_id_operand);
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	idr_pre_get(&cm.local_id_table, GFP_KERNEL);
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	cm.wq = create_workqueue("ib_cm");
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