From: Feras Daoud <ferasda@mellanox.com>
Date: Wed, 28 Dec 2016 12:47:27 +0000 (+0200)
Subject: IB/ipoib: Replace list_del of the neigh->list with list_del_init
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c586071d1dc8227a7182179b8e50ee92cc43f6d2;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

IB/ipoib: Replace list_del of the neigh->list with list_del_init

In order to resolve a situation where a few process delete
the same list element in sequence and cause panic, list_del
is replaced with list_del_init. In this case if the first
process that calls list_del releases the lock before acquiring
it again, other processes who can acquire the lock will call
list_del_init.

Fixes: b63b70d87741 ("IPoIB: Use a private hash table for path lookup")
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
---

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 1086858f1cbf..ee32a2a87e2d 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -1297,7 +1297,7 @@ static void __ipoib_reap_neigh(struct ipoib_dev_priv *priv)
 						   rcu_dereference_protected(neigh->hnext,
 									     lockdep_is_held(&priv->lock)));
 				/* remove from path/mc list */
-				list_del(&neigh->list);
+				list_del_init(&neigh->list);
 				call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 			} else {
 				np = &neigh->hnext;
@@ -1461,7 +1461,7 @@ void ipoib_neigh_free(struct ipoib_neigh *neigh)
 					   rcu_dereference_protected(neigh->hnext,
 								     lockdep_is_held(&priv->lock)));
 			/* remove from parent list */
-			list_del(&neigh->list);
+			list_del_init(&neigh->list);
 			call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 			return;
 		} else {
@@ -1546,7 +1546,7 @@ void ipoib_del_neighs_by_gid(struct net_device *dev, u8 *gid)
 						   rcu_dereference_protected(neigh->hnext,
 									     lockdep_is_held(&priv->lock)));
 				/* remove from parent list */
-				list_del(&neigh->list);
+				list_del_init(&neigh->list);
 				call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 			} else {
 				np = &neigh->hnext;
@@ -1588,7 +1588,7 @@ static void ipoib_flush_neighs(struct ipoib_dev_priv *priv)
 					   rcu_dereference_protected(neigh->hnext,
 								     lockdep_is_held(&priv->lock)));
 			/* remove from path/mc list */
-			list_del(&neigh->list);
+			list_del_init(&neigh->list);
 			call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 		}
 	}