[PATCH] Clean up ocfs2 hash probe and make it faster

Signed-Off-By: Daniel Phillips <phillips@google.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 14 insertions, 15 deletions

diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index a818fde24476..595b1c7cbd1f 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -103,28 +103,27 @@ struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
                                                 unsigned int len,
                                                 unsigned int hash)
 {
-        struct hlist_node *iter;
-        struct dlm_lock_resource *tmpres=NULL;
         struct hlist_head *bucket;
+        struct hlist_node *list;
 
         mlog_entry("%.*s\n", len, name);
 
         assert_spin_locked(&dlm->spinlock);
 
-        bucket = &(dlm->lockres_hash[hash % DLM_HASH_BUCKETS]);
-
-        /* check for pre-existing lock */
-        hlist_for_each(iter, bucket) {
-                tmpres = hlist_entry(iter, struct dlm_lock_resource, hash_node);
-                if (tmpres->lockname.len == len &&
-                    memcmp(tmpres->lockname.name, name, len) == 0) {
-                        dlm_lockres_get(tmpres);
-                        break;
-                }
-
-                tmpres = NULL;
+        bucket = dlm->lockres_hash + full_name_hash(name, len) % DLM_HASH_BUCKETS;
+        hlist_for_each(list, bucket) {
+                struct dlm_lock_resource *res = hlist_entry(list,
+                        struct dlm_lock_resource, hash_node);
+                if (res->lockname.name[0] != name[0])
+                        continue;
+                if (unlikely(res->lockname.len != len))
+                        continue;
+                if (memcmp(res->lockname.name + 1, name + 1, len - 1))
+                        continue;
+                dlm_lockres_get(res);
+                return res;
         }
-        return tmpres;
+        return NULL;
 }
 
 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,