[patch 3/4] vfs: fix ERR_PTR abuse in generic_readlink

generic_readlink calls ERR_PTR for negative and positive values
(vfs_readlink returns length of "link"), but it should not
(not an errno) and does not need to.

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 7 deletions

diff --git a/fs/namei.c b/fs/namei.c
index ee1544696e83..01e67dddcc3d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2856,16 +2856,17 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
         struct nameidata nd;
         void *cookie;
+        int res;
 
         nd.depth = 0;
         cookie = dentry->d_inode->i_op->follow_link(dentry, &nd);
-        if (!IS_ERR(cookie)) {
-                int res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
-                if (dentry->d_inode->i_op->put_link)
-                        dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
-                cookie = ERR_PTR(res);
-        }
-        return PTR_ERR(cookie);
+        if (IS_ERR(cookie))
+                return PTR_ERR(cookie);
+
+        res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
+        if (dentry->d_inode->i_op->put_link)
+                dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
+        return res;
 }
 
 int vfs_follow_link(struct nameidata *nd, const char *link)