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>

1 files changed, 12 insertions, 12 deletions

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index e5601dc24088..a7708b7c957f 100644
--- 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;