From 75c5a2e788ab02f67931442e8dcbc854ae7252d1 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Tue, 8 May 2012 22:31:57 +0200 Subject: [PATCH] batman-adv: fix locking in hash_add() To ensure an entry isn't added twice all comparisons have to be protected by the hash line write spinlock. This doesn't really hurt as the case that it is tried to add an element already present to the hash shouldn't occur very often, so in most cases the lock would have have to be taken anyways. Signed-off-by: Matthias Schiffer Acked-by: Sven Eckelmann Signed-off-by: Sven Eckelmann --- net/batman-adv/hash.h | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h index 93b3c71aeaf8..3d67ce49fc31 100644 --- a/net/batman-adv/hash.h +++ b/net/batman-adv/hash.h @@ -110,26 +110,23 @@ static inline int hash_add(struct hashtable_t *hash, head = &hash->table[index]; list_lock = &hash->list_locks[index]; - rcu_read_lock(); - __hlist_for_each_rcu(node, head) { + spin_lock_bh(list_lock); + + hlist_for_each(node, head) { if (!compare(node, data)) continue; ret = 1; - goto err_unlock; + goto unlock; } - rcu_read_unlock(); /* no duplicate found in list, add new element */ - spin_lock_bh(list_lock); hlist_add_head_rcu(data_node, head); - spin_unlock_bh(list_lock); ret = 0; - goto out; -err_unlock: - rcu_read_unlock(); +unlock: + spin_unlock_bh(list_lock); out: return ret; } -- 2.20.1