cifs: constify get_normalized_path() properly

As it is, it takes const char * and, in some cases, stores it in
caller's variable that is plain char *.  Fortunately, none of the
callers actually proceeded to modify the string via now-non-const
alias, but that's trouble waiting to happen.

It's easy to do properly, anyway...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/dfs_cache.c

@@ -81,23 +81,24 @@ static void refresh_cache_worker(struct work_struct *work);
 
 static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker);
 
-static int get_normalized_path(const char *path, char **npath)
+static int get_normalized_path(const char *path, const char **npath)
 {
 	if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/'))
 		return -EINVAL;
 
 	if (*path == '\\') {
-		*npath = (char *)path;
+		*npath = path;
 	} else {
-		*npath = kstrdup(path, GFP_KERNEL);
-		if (!*npath)
+		char *s = kstrdup(path, GFP_KERNEL);
+		if (!s)
 			return -ENOMEM;
-		convert_delimiter(*npath, '\\');
+		convert_delimiter(s, '\\');
+		*npath = s;
 	}
 	return 0;
 }
 
-static inline void free_normalized_path(const char *path, char *npath)
+static inline void free_normalized_path(const char *path, const char *npath)
 {
 	if (path != npath)
 		kfree(npath);
@@ -882,7 +883,7 @@ int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses,
 		   struct dfs_cache_tgt_list *tgt_list)
 {
 	int rc;
-	char *npath;
+	const char *npath;
 	struct cache_entry *ce;
 
 	rc = get_normalized_path(path, &npath);
@@ -936,7 +937,7 @@ int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
 			 struct dfs_cache_tgt_list *tgt_list)
 {
 	int rc;
-	char *npath;
+	const char *npath;
 	struct cache_entry *ce;
 
 	rc = get_normalized_path(path, &npath);
@@ -991,7 +992,7 @@ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses,
 			     const struct dfs_cache_tgt_iterator *it)
 {
 	int rc;
-	char *npath;
+	const char *npath;
 	struct cache_entry *ce;
 	struct cache_dfs_tgt *t;
 
@@ -1053,7 +1054,7 @@ int dfs_cache_noreq_update_tgthint(const char *path,
 				   const struct dfs_cache_tgt_iterator *it)
 {
 	int rc;
-	char *npath;
+	const char *npath;
 	struct cache_entry *ce;
 	struct cache_dfs_tgt *t;
 
@@ -1111,7 +1112,7 @@ int dfs_cache_get_tgt_referral(const char *path,
 			       struct dfs_info3_param *ref)
 {
 	int rc;
-	char *npath;
+	const char *npath;
 	struct cache_entry *ce;
 
 	if (!it || !ref)
@@ -1484,7 +1485,7 @@ static int refresh_tcon(struct vol_info *vi, struct cifs_tcon *tcon)
 {
 	int rc = 0;
 	unsigned int xid;
-	char *path, *npath;
+	const char *path, *npath;
 	struct cache_entry *ce;
 	struct cifs_ses *root_ses = NULL, *ses;
 	struct dfs_info3_param *refs = NULL;