File aufs-factor-out-__lookup_one_len of Package aufs

From: Jeff Mahoney <jeffm@suse.com>
Subject: aufs: Factor out __lookup_one_len

 The existing code acknowledges that it's just open coding __lookup_one_len,
 so why not just copy the function entirely and call it. If the code is
 ever merged with mainline, it will be an obvious thing to rename
 and export rather than having two copies of it.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 fs/aufs25/br_nfs.c |   43 +++++++++++++++++++++++++------------------
 1 file changed, 25 insertions(+), 18 deletions(-)

--- a/fs/aufs25/br_nfs.c
+++ b/fs/aufs25/br_nfs.c
@@ -231,6 +231,28 @@ int au_hin_after_reval(struct nameidata
 	return err;
 }
 
+static int __lookup_one_len(const char *name, struct qstr *this,
+		struct dentry *base, int len)
+{
+	unsigned long hash;
+	unsigned int c;
+
+	this->name = name;
+	this->len = len;
+	if (!len)
+		return -EACCES;
+
+	hash = init_name_hash();
+	while (len--) {
+		c = *(const unsigned char *)name++;
+		if (c == '/' || c == '\0')
+			return -EACCES;
+		hash = partial_name_hash(c, hash);
+	}
+	this->hash = end_name_hash(hash);
+	return 0;
+}
+
 #ifdef CONFIG_AUFS_DLGT
 struct au_lookup_hash_args {
 	struct dentry **errp;
@@ -285,32 +307,17 @@ struct dentry *au_lkup_hash(const char *
 			    int len, struct au_ndx *ndx)
 {
 	struct dentry *dentry;
-	char *p;
-	unsigned long hash;
 	struct qstr this;
-	unsigned int c;
 	struct nameidata tmp_nd, *ndo;
 	int err;
 
 	LKTRTrace("%.*s/%.*s\n", AuDLNPair(parent), len, name);
 
-	/* todo: export and call __lookup_one_len() in fs/namei.c? */
-	dentry = ERR_PTR(-EACCES);
-	this.name = name;
-	this.len = len;
-	if (unlikely(!len))
+	err = __lookup_one_len(name, &this, parent, len);
+	dentry = ERR_PTR(err);
+	if (err)
 		goto out;
 
-	p = (void *)name;
-	hash = init_name_hash();
-	while (len--) {
-		c = *p++;
-		if (unlikely(c == '/' || c == '\0'))
-			goto out;
-		hash = partial_name_hash(c, hash);
-	}
-	this.hash = end_name_hash(hash);
-
 	ndo = ndx->nd;
 	if (ndo) {
 		tmp_nd = *ndo;