netdev - [PATCH 13/20] batman-adv: Place kref_get for hard

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Message-Id: <20160822135620.15337-14-sw@simonwunderlich.de>
Date:   Mon, 22 Aug 2016 15:56:13 +0200
From:   Simon Wunderlich <sw@...onwunderlich.de>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
        Sven Eckelmann <sven@...fation.org>,
        Marek Lindner <mareklindner@...mailbox.ch>,
        Simon Wunderlich <sw@...onwunderlich.de>
Subject: [PATCH 13/20] batman-adv: Place kref_get for hard_iface near use

From: Sven Eckelmann <sven@...fation.org>

It is hard to understand why the refcnt is increased when it isn't done
near the actual place the new reference is used. So using kref_get right
before the place which requires the reference and in the same function
helps to avoid accidental problems caused by incorrect reference counting.

Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Marek Lindner <mareklindner@...mailbox.ch>
Signed-off-by: Simon Wunderlich <sw@...onwunderlich.de>
---
 net/batman-adv/hard-interface.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 43c9a3e..9284c73 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -694,6 +694,7 @@ batadv_hardif_add_interface(struct net_device *net_dev)
 	INIT_HLIST_HEAD(&hard_iface->neigh_list);
 
 	spin_lock_init(&hard_iface->neigh_list_lock);
+	kref_init(&hard_iface->refcount);
 
 	hard_iface->num_bcasts = BATADV_NUM_BCASTS_DEFAULT;
 	if (batadv_is_wifi_netdev(net_dev))
@@ -701,11 +702,8 @@ batadv_hardif_add_interface(struct net_device *net_dev)
 
 	batadv_v_hardif_init(hard_iface);
 
-	/* extra reference for return */
-	kref_init(&hard_iface->refcount);
-	kref_get(&hard_iface->refcount);
-
 	batadv_check_known_mac_addr(hard_iface->net_dev);
+	kref_get(&hard_iface->refcount);
 	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
 
 	return hard_iface;
-- 
2.9.3