1 files changed, 5 insertions, 56 deletions

diff --git a/fs/proc/root.c b/fs/proc/root.c
index 06702783bf40..8d3e484055a6 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -23,21 +23,6 @@
 
 #include "internal.h"
 
-static int proc_test_super(struct super_block *sb, void *data)
-{
-        return sb->s_fs_info == data;
-}
-
-static int proc_set_super(struct super_block *sb, void *data)
-{
-        int err = set_anon_super(sb, NULL);
-        if (!err) {
-                struct pid_namespace *ns = (struct pid_namespace *)data;
-                sb->s_fs_info = get_pid_ns(ns);
-        }
-        return err;
-}
-
 enum {
         Opt_gid, Opt_hidepid, Opt_err,
 };
@@ -48,7 +33,7 @@ static const match_table_t tokens = {
         {Opt_err, NULL},
 };
 
-static int proc_parse_options(char *options, struct pid_namespace *pid)
+int proc_parse_options(char *options, struct pid_namespace *pid)
 {
         char *p;
         substring_t args[MAX_OPT_ARGS];
@@ -100,52 +85,16 @@ int proc_remount(struct super_block *sb, int *flags, char *data)
 static struct dentry *proc_mount(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data)
 {
-        int err;
-        struct super_block *sb;
         struct pid_namespace *ns;
-        char *options;
 
         if (flags & MS_KERNMOUNT) {
-                ns = (struct pid_namespace *)data;
-                options = NULL;
+                ns = data;
+                data = NULL;
         } else {
                 ns = task_active_pid_ns(current);
-                options = data;
-
-                /* Does the mounter have privilege over the pid namespace? */
-                if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
-                        return ERR_PTR(-EPERM);
-        }
-
-        sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
-        if (IS_ERR(sb))
-                return ERR_CAST(sb);
-
-        /*
-         * procfs isn't actually a stacking filesystem; however, there is
-         * too much magic going on inside it to permit stacking things on
-         * top of it
-         */
-        sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
-
-        if (!proc_parse_options(options, ns)) {
-                deactivate_locked_super(sb);
-                return ERR_PTR(-EINVAL);
-        }
-
-        if (!sb->s_root) {
-                err = proc_fill_super(sb);
-                if (err) {
-                        deactivate_locked_super(sb);
-                        return ERR_PTR(err);
-                }
-
-                sb->s_flags |= MS_ACTIVE;
-                /* User space would break if executables appear on proc */
-                sb->s_iflags |= SB_I_NOEXEC;
         }
 
-        return dget(sb->s_root);
+        return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
 }
 
 static void proc_kill_sb(struct super_block *sb)
@@ -165,7 +114,7 @@ static struct file_system_type proc_fs_type = {
         .name           = "proc",
         .mount          = proc_mount,
         .kill_sb        = proc_kill_sb,
-        .fs_flags       = FS_USERNS_VISIBLE | FS_USERNS_MOUNT,
+        .fs_flags       = FS_USERNS_MOUNT,
 };
 
 void __init proc_root_init(void)