Revision dd04265b028c00c365a78f9ff78a05e217f98656 authored by Linus Torvalds on 07 March 2010, 23:56:25 UTC, committed by Linus Torvalds on 07 March 2010, 23:56:25 UTC
* 'for-linus/i2c' of git://git.fluff.org/bjdooks/linux: i2c: Add support for Xilinx XPS IIC Bus Interface i2c: omap: Add support for 16-bit registers i2c-pnx: fix setting start/stop condition powerpc: doc/dts-bindings: update doc of FSL I2C bindings i2c-mpc: add support for the MPC512x processors from Freescale i2c-mpc: rename "setclock" initialization functions to "setup" i2c-mpc: use __devinit[data] for initialization functions and data i2c/imx: don't add probe function to the driver struct i2c: Add support for Ux500/Nomadik I2C controller
is_single_threaded.c
/* Function to determine if a thread group is single threaded or not
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from security/selinux/hooks.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/sched.h>
/*
* Returns true if the task does not share ->mm with another thread/process.
*/
bool current_is_single_threaded(void)
{
struct task_struct *task = current;
struct mm_struct *mm = task->mm;
struct task_struct *p, *t;
bool ret;
if (atomic_read(&task->signal->live) != 1)
return false;
if (atomic_read(&mm->mm_users) == 1)
return true;
ret = false;
rcu_read_lock();
for_each_process(p) {
if (unlikely(p->flags & PF_KTHREAD))
continue;
if (unlikely(p == task->group_leader))
continue;
t = p;
do {
if (unlikely(t->mm == mm))
goto found;
if (likely(t->mm))
break;
/*
* t->mm == NULL. Make sure next_thread/next_task
* will see other CLONE_VM tasks which might be
* forked before exiting.
*/
smp_rmb();
} while_each_thread(p, t);
}
ret = true;
found:
rcu_read_unlock();
return ret;
}
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