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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - lib/is_single_threaded.c
1 /* Function to determine if a thread group is single threaded or not
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from security/selinux/hooks.c
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
13 #include <linux/sched.h>
16 * is_single_threaded - Determine if a thread group is single-threaded or not
17 * @p: A task in the thread group in question
19 * This returns true if the thread group to which a task belongs is single
20 * threaded, false if it is not.
22 bool is_single_threaded(struct task_struct
*p
)
24 struct task_struct
*g
, *t
;
25 struct mm_struct
*mm
= p
->mm
;
27 if (atomic_read(&p
->signal
->count
) != 1)
30 if (atomic_read(&p
->mm
->mm_users
) != 1) {
31 read_lock(&tasklist_lock
);
32 do_each_thread(g
, t
) {
33 if (t
->mm
== mm
&& t
!= p
)
35 } while_each_thread(g
, t
);
36 read_unlock(&tasklist_lock
);
42 read_unlock(&tasklist_lock
);