Merge branch 'salted-string-hash'

This changes the vfs dentry hashing to mix in the parent pointer at the
_beginning_ of the hash, rather than at the end.

That actually improves both the hash and the code generation, because we
can move more of the computation to the "static" part of the dcache
setup, and do less at lookup runtime.

It turns out that a lot of other hash users also really wanted to mix in
a base pointer as a 'salt' for the hash, and so the slightly extended
interface ends up working well for other cases too.

Users that want a string hash that is purely about the string pass in a
'salt' pointer of NULL.

* merge branch 'salted-string-hash':
  fs/dcache.c: Save one 32-bit multiply in dcache lookup
  vfs: make the string hashes salt the hash

3 files changed, 4 insertions, 4 deletions

diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index a283f9e796c1..23e5808a0970 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -413,7 +413,7 @@ void smk_insert_entry(struct smack_known *skp)
 	unsigned int hash;
 	struct hlist_head *head;
 
-	hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
+	hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
 	head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
 
 	hlist_add_head_rcu(&skp->smk_hashed, head);
@@ -433,7 +433,7 @@ struct smack_known *smk_find_entry(const char *string)
 	struct hlist_head *head;
 	struct smack_known *skp;
 
-	hash = full_name_hash(string, strlen(string));
+	hash = full_name_hash(NULL, string, strlen(string));
 	head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
 
 	hlist_for_each_entry_rcu(skp, head, smk_hashed)
diff --git a/security/tomoyo/memory.c b/security/tomoyo/memory.c
index 0e995716cc25..1598b559ac42 100644
--- a/security/tomoyo/memory.c
+++ b/security/tomoyo/memory.c
@@ -154,7 +154,7 @@ const struct tomoyo_path_info *tomoyo_get_name(const char *name)
 	if (!name)
 		return NULL;
 	len = strlen(name) + 1;
-	hash = full_name_hash((const unsigned char *) name, len - 1);
+	hash = full_name_hash(NULL, (const unsigned char *) name, len - 1);
 	head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
 	if (mutex_lock_interruptible(&tomoyo_policy_lock))
 		return NULL;
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index b974a6997d7f..5fe3679137ae 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -666,7 +666,7 @@ void tomoyo_fill_path_info(struct tomoyo_path_info *ptr)
 	ptr->const_len = tomoyo_const_part_length(name);
 	ptr->is_dir = len && (name[len - 1] == '/');
 	ptr->is_patterned = (ptr->const_len < len);
-	ptr->hash = full_name_hash(name, len);
+	ptr->hash = full_name_hash(NULL, name, len);
 }
 
 /**