sysctl: Don't call sysctl_follow_link unless we are a link.

There are no functional changes.  Just code motion to make it
clear that we don't follow a link between sysctl roots unless the
directory entry actually is a link.

Suggested-by:  Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index e5601dc240883d552bbb889e02d43279b8b05c64..a7708b7c957ff8a8b1d9bb7c2b3f37ee25745310 100644 (file)
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -451,10 +451,12 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
        if (!p)
                goto out;
 
-       ret = sysctl_follow_link(&h, &p, current->nsproxy);
-       err = ERR_PTR(ret);
-       if (ret)
-               goto out;
+       if (S_ISLNK(p->mode)) {
+               ret = sysctl_follow_link(&h, &p, current->nsproxy);
+               err = ERR_PTR(ret);
+               if (ret)
+                       goto out;
+       }
 
        err = ERR_PTR(-ENOMEM);
        inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
@@ -601,10 +603,12 @@ static int proc_sys_link_fill_cache(struct file *filp, void *dirent,
        int err, ret = 0;
        head = sysctl_head_grab(head);
 
-       /* It is not an error if we can not follow the link ignore it */
-       err = sysctl_follow_link(&head, &table, current->nsproxy);
-       if (err)
-               goto out;
+       if (S_ISLNK(table->mode)) {
+               /* It is not an error if we can not follow the link ignore it */
+               err = sysctl_follow_link(&head, &table, current->nsproxy);
+               if (err)
+                       goto out;
+       }
 
        ret = proc_sys_fill_cache(filp, dirent, filldir, head, table);
 out:
@@ -950,10 +954,6 @@ static int sysctl_follow_link(struct ctl_table_header **phead,
        struct ctl_dir *dir;
        int ret;
 
-       /* Get out quickly if not a link */
-       if (!S_ISLNK((*pentry)->mode))
-               return 0;
-
        ret = 0;
        spin_lock(&sysctl_lock);
        root = (*pentry)->data;