constify tomoyo_realpath_from_path()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h
index b897d48..6627102 100644
--- a/security/tomoyo/common.h
+++ b/security/tomoyo/common.h
@@ -945,7 +945,7 @@
 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 		      va_list args);
 char *tomoyo_read_token(struct tomoyo_acl_param *param);
-char *tomoyo_realpath_from_path(struct path *path);
+char *tomoyo_realpath_from_path(const struct path *path);
 char *tomoyo_realpath_nofollow(const char *pathname);
 const char *tomoyo_get_exe(void);
 const char *tomoyo_yesno(const unsigned int value);
diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c
index bed745c..1e0d480 100644
--- a/security/tomoyo/realpath.c
+++ b/security/tomoyo/realpath.c
@@ -89,7 +89,7 @@
  *
  * If dentry is a directory, trailing '/' is appended.
  */
-static char *tomoyo_get_absolute_path(struct path *path, char * const buffer,
+static char *tomoyo_get_absolute_path(const struct path *path, char * const buffer,
 				      const int buflen)
 {
 	char *pos = ERR_PTR(-ENOMEM);
@@ -216,7 +216,7 @@
  *
  * Returns the buffer.
  */
-static char *tomoyo_get_socket_name(struct path *path, char * const buffer,
+static char *tomoyo_get_socket_name(const struct path *path, char * const buffer,
 				    const int buflen)
 {
 	struct inode *inode = path->dentry->d_inode;
@@ -247,7 +247,7 @@
  * These functions use kzalloc(), so the caller must call kfree()
  * if these functions didn't return NULL.
  */
-char *tomoyo_realpath_from_path(struct path *path)
+char *tomoyo_realpath_from_path(const struct path *path)
 {
 	char *buf = NULL;
 	char *name = NULL;