namei: move link/cookie pairs into nameidata

Array of MAX_NESTED_LINKS + 1 elements put into nameidata;
what used to be a local array in link_path_walk() occupies
entries 1 .. MAX_NESTED_LINKS in it, link and cookie from
the trailing symlink handling loops - entry 0.

This is _not_ the final arrangement; just an easily verified
incremental step.

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

diff --git a/fs/namei.c b/fs/namei.c
index c105107ddf8f004615f153cd4ec8179d018e7aaf..d4b238a58739797dd21c021367e45aeb13908601 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -505,6 +505,11 @@ struct nameidata {
        int             last_type;
        unsigned        depth;
        struct file     *base;
+       struct saved {
+               struct path link;
+               void *cookie;
+               const char *name;
+       } stack[MAX_NESTED_LINKS + 1];
 };
 
 /*
@@ -1711,11 +1716,7 @@ static inline u64 hash_name(const char *name)
  */
 static int link_path_walk(const char *name, struct nameidata *nd)
 {
-       struct saved {
-               struct path link;
-               void *cookie;
-               const char *name;
-       } stack[MAX_NESTED_LINKS], *last = stack + nd->depth - 1;
+       struct saved *last = nd->stack;
        int err;
 
        while (*name=='/')
@@ -2030,13 +2031,13 @@ static int path_lookupat(int dfd, const struct filename *name,
        if (!err && !(flags & LOOKUP_PARENT)) {
                err = lookup_last(nd);
                while (err > 0) {
-                       void *cookie;
-                       struct path link = nd->link;
-                       err = trailing_symlink(&link, nd, &cookie);
+                       nd->stack[0].link = nd->link;
+                       err = trailing_symlink(&nd->stack[0].link,
+                                               nd, &nd->stack[0].cookie);
                        if (err)
                                break;
                        err = lookup_last(nd);
-                       put_link(nd, &link, cookie);
+                       put_link(nd, &nd->stack[0].link, nd->stack[0].cookie);
                }
        }
 
@@ -2376,13 +2377,13 @@ path_mountpoint(int dfd, const struct filename *name, struct path *path,
 
        err = mountpoint_last(nd, path);
        while (err > 0) {
-               void *cookie;
-               struct path link = *path;
-               err = trailing_symlink(&link, nd, &cookie);
+               nd->stack[0].link = nd->link;
+               err = trailing_symlink(&nd->stack[0].link,
+                                       nd, &nd->stack[0].cookie);
                if (err)
                        break;
                err = mountpoint_last(nd, path);
-               put_link(nd, &link, cookie);
+               put_link(nd, &nd->stack[0].link, nd->stack[0].cookie);
        }
 out:
        path_cleanup(nd);
@@ -3259,14 +3260,14 @@ static struct file *path_openat(int dfd, struct filename *pathname,
 
        error = do_last(nd, file, op, &opened, pathname);
        while (unlikely(error > 0)) { /* trailing symlink */
-               struct path link = nd->link;
-               void *cookie;
                nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
-               error = trailing_symlink(&link, nd, &cookie);
+               nd->stack[0].link = nd->link;
+               error= trailing_symlink(&nd->stack[0].link,
+                                       nd, &nd->stack[0].cookie);
                if (unlikely(error))
                        break;
                error = do_last(nd, file, op, &opened, pathname);
-               put_link(nd, &link, cookie);
+               put_link(nd, &nd->stack[0].link, nd->stack[0].cookie);
        }
 out:
        path_cleanup(nd);