1 files changed, 44 insertions, 22 deletions

diff --git a/fs/namei.c b/fs/namei.c
index a780ea515c47..e2ba62820a0f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1374,6 +1374,34 @@ static inline int can_lookup(struct inode *inode)
         return 1;
 }
 
+unsigned int full_name_hash(const unsigned char *name, unsigned int len)
+{
+        unsigned long hash = init_name_hash();
+        while (len--)
+                hash = partial_name_hash(*name++, hash);
+        return end_name_hash(hash);
+}
+EXPORT_SYMBOL(full_name_hash);
+
+/*
+ * We know there's a real path component here of at least
+ * one character.
+ */
+static inline unsigned long hash_name(const char *name, unsigned int *hashp)
+{
+        unsigned long hash = init_name_hash();
+        unsigned long len = 0, c;
+
+        c = (unsigned char)*name;
+        do {
+                len++;
+                hash = partial_name_hash(c, hash);
+                c = (unsigned char)name[len];
+        } while (c && c != '/');
+        *hashp = end_name_hash(hash);
+        return len;
+}
+
 /*
  * Name resolution.
  * This is the basic name resolution function, turning a pathname into
@@ -1394,31 +1422,22 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 
         /* At this point we know we have a real path component. */
         for(;;) {
-                unsigned long hash;
                 struct qstr this;
-                unsigned int c;
+                long len;
                 int type;
 
                 err = may_lookup(nd);
                 if (err)
                         break;
 
+                len = hash_name(name, &this.hash);
                 this.name = name;
-                c = *(const unsigned char *)name;
-
-                hash = init_name_hash();
-                do {
-                        name++;
-                        hash = partial_name_hash(c, hash);
-                        c = *(const unsigned char *)name;
-                } while (c && (c != '/'));
-                this.len = name - (const char *) this.name;
-                this.hash = end_name_hash(hash);
+                this.len = len;
 
                 type = LAST_NORM;
-                if (this.name[0] == '.') switch (this.len) {
+                if (name[0] == '.') switch (len) {
                         case 2:
-                                if (this.name[1] == '.') {
+                                if (name[1] == '.') {
                                         type = LAST_DOTDOT;
                                         nd->flags |= LOOKUP_JUMPED;
                                 }
@@ -1437,12 +1456,18 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                         }
                 }
 
-                /* remove trailing slashes? */
-                if (!c)
+                if (!name[len])
                         goto last_component;
-                while (*++name == '/');
-                if (!*name)
+                /*
+                 * If it wasn't NUL, we know it was '/'. Skip that
+                 * slash, and continue until no more slashes.
+                 */
+                do {
+                        len++;
+                } while (unlikely(name[len] == '/'));
+                if (!name[len])
                         goto last_component;
+                name += len;
 
                 err = walk_component(nd, &next, &this, type, LOOKUP_FOLLOW);
                 if (err < 0)
@@ -1775,24 +1800,21 @@ static struct dentry *lookup_hash(struct nameidata *nd)
 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 {
         struct qstr this;
-        unsigned long hash;
         unsigned int c;
 
         WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex));
 
         this.name = name;
         this.len = len;
+        this.hash = full_name_hash(name, len);
         if (!len)
                 return ERR_PTR(-EACCES);
 
-        hash = init_name_hash();
         while (len--) {
                 c = *(const unsigned char *)name++;
                 if (c == '/' || c == '\0')
                         return ERR_PTR(-EACCES);
-                hash = partial_name_hash(c, hash);
         }
-        this.hash = end_name_hash(hash);
         /*
          * See if the low-level filesystem might want
          * to use its own hash..