fold handle_mounts() into step_into()

The following is true:
	* calls of handle_mounts() and step_into() are always
paired in sequences like
	err = handle_mounts(nd, dentry, &path, &inode, &seq);
	if (unlikely(err < 0))
		return err;
	err = step_into(nd, &path, flags, inode, seq);
	* in all such sequences path is uninitialized before and
unused after this pair of calls
	* in all such sequences inode and seq are unused afterwards.

So the call of handle_mounts() can be shifted inside step_into(),
turning 'path' into a local variable in the combined function.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 79f06be..8a673f4 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1835,29 +1835,33 @@ enum {WALK_FOLLOW = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};
  * so we keep a cache of "no, this doesn't need follow_link"
  * for the common case.
  */
-static inline int step_into(struct nameidata *nd, struct path *path,
-                           int flags, struct inode *inode, unsigned seq)
+static int step_into(struct nameidata *nd, int flags,
+                    struct dentry *dentry, struct inode *inode, unsigned seq)
 {
-       if (likely(!d_is_symlink(path->dentry)) ||
+       struct path path;
+       int err = handle_mounts(nd, dentry, &path, &inode, &seq);
+
+       if (err < 0)
+               return err;
+       if (likely(!d_is_symlink(path.dentry)) ||
           !((flags & WALK_FOLLOW) || (nd->flags & LOOKUP_FOLLOW)) ||
           (flags & WALK_NOFOLLOW)) {
                /* not a symlink or should not follow */
-               path_to_nameidata(path, nd);
+               path_to_nameidata(&path, nd);
                nd->inode = inode;
                nd->seq = seq;
                return 0;
        }
        /* make sure that d_is_symlink above matches inode */
        if (nd->flags & LOOKUP_RCU) {
-               if (read_seqcount_retry(&path->dentry->d_seq, seq))
+               if (read_seqcount_retry(&path.dentry->d_seq, seq))
                        return -ECHILD;
        }
-       return pick_link(nd, path, inode, seq);
+       return pick_link(nd, &path, inode, seq);
 }
 
 static int walk_component(struct nameidata *nd, int flags)
 {
-       struct path path;
        struct dentry *dentry;
        struct inode *inode;
        unsigned seq;
@@ -1883,11 +1887,7 @@ static int walk_component(struct nameidata *nd, int flags)
        }
        if (!(flags & WALK_MORE) && nd->depth)
                put_link(nd);
-
-       err = handle_mounts(nd, dentry, &path, &inode, &seq);
-       if (unlikely(err < 0))
-                       return err;
-       return step_into(nd, &path, flags, inode, seq);
+       return step_into(nd, flags, dentry, inode, seq);
 }
 
 /*
@@ -2354,17 +2354,10 @@ static inline int lookup_last(struct nameidata *nd)
 
 static int handle_lookup_down(struct nameidata *nd)
 {
-       struct path path;
-       struct inode *inode = nd->inode;
-       unsigned seq = nd->seq;
-       int err;
-
        if (!(nd->flags & LOOKUP_RCU))
                dget(nd->path.dentry);
-       err = handle_mounts(nd, nd->path.dentry, &path, &inode, &seq);
-       if (unlikely(err < 0))
-               return err;
-       return step_into(nd, &path, WALK_NOFOLLOW, inode, seq);
+       return step_into(nd, WALK_NOFOLLOW,
+                       nd->path.dentry, nd->inode, nd->seq);
 }
 
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
@@ -3281,7 +3274,6 @@ static int do_last(struct nameidata *nd,
        int acc_mode = op->acc_mode;
        unsigned seq;
        struct inode *inode;
-       struct path path;
        struct dentry *dentry;
        int error;
 
@@ -3384,10 +3376,7 @@ static int do_last(struct nameidata *nd,
 finish_lookup:
        if (nd->depth)
                put_link(nd);
-       error = handle_mounts(nd, dentry, &path, &inode, &seq);
-       if (unlikely(error < 0))
-               return error;
-       error = step_into(nd, &path, 0, inode, seq);
+       error = step_into(nd, 0, dentry, inode, seq);
        if (unlikely(error))
                return error;