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rhashtable: Avoid calculating hash again to unlock

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

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Thomas Graf
2015-03-16 10:42:26 +01:00
committed by David S. Miller
parent 9f1ab18672
commit 617011e7d5
1 changed files with 5 additions and 6 deletions
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11
lib/rhashtable.c
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@@ -384,14 +384,16 @@ static bool __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
struct rhash_head *head; struct rhash_head *head;
bool no_resize_running; bool no_resize_running;
unsigned hash; unsigned hash;
spinlock_t *old_lock;
bool success = true; bool success = true;
rcu_read_lock(); rcu_read_lock();
old_tbl = rht_dereference_rcu(ht->tbl, ht); old_tbl = rht_dereference_rcu(ht->tbl, ht);
hash = head_hashfn(ht, old_tbl, obj); 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, /* Because we have already taken the bucket lock in old_tbl,
* if we find that future_tbl is not yet visible then that * 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); schedule_work(&ht->run_work);
exit: exit:
if (tbl != old_tbl) { if (tbl != old_tbl)
hash = head_hashfn(ht, tbl, obj);
spin_unlock(bucket_lock(tbl, hash)); spin_unlock(bucket_lock(tbl, hash));
}
hash = head_hashfn(ht, old_tbl, obj); spin_unlock_bh(old_lock);
spin_unlock_bh(bucket_lock(old_tbl, hash));
rcu_read_unlock(); rcu_read_unlock();