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[18/19] batman-adv: fix locking in hash_add()

Message ID 1340051963-14836-19-git-send-email-ordex@autistici.org
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Antonio Quartulli June 18, 2012, 8:39 p.m. UTC 
From: Matthias Schiffer <mschiffer@universe-factory.net>

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 <mschiffer@universe-factory.net>
Acked-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
---
 net/batman-adv/hash.h |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)
diff mbox

Patch

diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h
index 93b3c71..3d67ce4 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;
 }