vfs: make the string hashes salt the hash

We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time.  It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.

A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.

Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.

Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/affs/namei.c b/fs/affs/namei.c
index 00d3002..eb32029 100644
--- a/fs/affs/namei.c
+++ b/fs/affs/namei.c
@@ -61,7 +61,7 @@
  * Note: the dentry argument is the parent dentry.
  */
 static inline int
-__affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
+__affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
 {
 	const u8 *name = qstr->name;
 	unsigned long hash;
@@ -72,7 +72,7 @@
 	if (retval)
 		return retval;
 
-	hash = init_name_hash();
+	hash = init_name_hash(dentry);
 	len = min(qstr->len, AFFSNAMEMAX);
 	for (; len > 0; name++, len--)
 		hash = partial_name_hash(toupper(*name), hash);
@@ -84,7 +84,7 @@
 static int
 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 {
-	return __affs_hash_dentry(qstr, affs_toupper,
+	return __affs_hash_dentry(dentry, qstr, affs_toupper,
 				  affs_nofilenametruncate(dentry));
 
 }
@@ -92,7 +92,7 @@
 static int
 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 {
-	return __affs_hash_dentry(qstr, affs_intl_toupper,
+	return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
 				  affs_nofilenametruncate(dentry));
 
 }