take post-lookup part of do_last() out of loop

now we can have open_last_lookups() directly from the loop in
path_openat() - the rest of do_last() never returns a symlink
to follow, so we can bloody well leave the loop first.

Rename the rest of that thing from do_last() to do_open() and
make it return an int.

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

diff --git a/fs/namei.c b/fs/namei.c
index e737d88..329ade3 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3220,31 +3220,26 @@ finish_lookup:
 /*
  * Handle the last step of open()
  */
-static const char *do_last(struct nameidata *nd,
+static int do_open(struct nameidata *nd,
                   struct file *file, const struct open_flags *op)
 {
        int open_flag = op->open_flag;
        bool do_truncate;
        int acc_mode;
-       const char *link;
        int error;
 
-       link = open_last_lookups(nd, file, op);
-       if (unlikely(link))
-               return link;
-
        if (!(file->f_mode & FMODE_CREATED))
                audit_inode(nd->name, nd->path.dentry, 0);
        if (open_flag & O_CREAT) {
                if (d_is_dir(nd->path.dentry))
-                       return ERR_PTR(-EISDIR);
+                       return -EISDIR;
                error = may_create_in_sticky(nd->dir_mode, nd->dir_uid,
                                             d_backing_inode(nd->path.dentry));
                if (unlikely(error))
-                       return ERR_PTR(error);
+                       return error;
        }
        if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
-               return ERR_PTR(-ENOTDIR);
+               return -ENOTDIR;
 
        do_truncate = false;
        acc_mode = op->acc_mode;
@@ -3255,7 +3250,7 @@ static const char *do_last(struct nameidata *nd,
        } else if (d_is_reg(nd->path.dentry) && open_flag & O_TRUNC) {
                error = mnt_want_write(nd->path.mnt);
                if (error)
-                       return ERR_PTR(error);
+                       return error;
                do_truncate = true;
        }
        error = may_open(&nd->path, acc_mode, open_flag);
@@ -3271,7 +3266,7 @@ static const char *do_last(struct nameidata *nd,
        }
        if (do_truncate)
                mnt_drop_write(nd->path.mnt);
-       return ERR_PTR(error);
+       return error;
 }
 
 struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
@@ -3374,8 +3369,10 @@ static struct file *path_openat(struct nameidata *nd,
        } else {
                const char *s = path_init(nd, flags);
                while (!(error = link_path_walk(s, nd)) &&
-                      (s = do_last(nd, file, op)) != NULL)
+                      (s = open_last_lookups(nd, file, op)) != NULL)
                        ;
+               if (!error)
+                       error = do_open(nd, file, op);
                terminate_walk(nd);
        }
        if (likely(!error)) {