Commit 617011e7 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

rhashtable: Avoid calculating hash again to unlock 



Caching the lock pointer avoids having to hash on the object
again to unlock the bucket locks.

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9f1ab186

lib/rhashtable.c

+5 −6
Original line number Diff line number Diff line
@@ -384,14 +384,16 @@ static bool __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj, 
	struct rhash_head *head;

	bool no_resize_running;

	unsigned hash;

	spinlock_t *old_lock;

	bool success = true;



	rcu_read_lock();



	old_tbl = rht_dereference_rcu(ht->tbl, ht);

	hash = head_hashfn(ht, old_tbl, obj);

	old_lock = bucket_lock(old_tbl, hash);



	spin_lock_bh(bucket_lock(old_tbl, hash));

	spin_lock_bh(old_lock);



	/* Because we have already taken the bucket lock in old_tbl,

	 * if we find that future_tbl is not yet visible then that
@@ -428,13 +430,10 @@ static bool __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj, 
		schedule_work(&ht->run_work);



exit:

	if (tbl != old_tbl) {

		hash = head_hashfn(ht, tbl, obj);

	if (tbl != old_tbl)

		spin_unlock(bucket_lock(tbl, hash));

	}



	hash = head_hashfn(ht, old_tbl, obj);

	spin_unlock_bh(bucket_lock(old_tbl, hash));

	spin_unlock_bh(old_lock);



	rcu_read_unlock();