https://github.com/torvalds/linux
Revision 2110cf029a67237db572299bb51e0de9e3e3d4dd authored by Linus Torvalds on 06 February 2013, 21:38:33 UTC, committed by Linus Torvalds on 06 February 2013, 21:38:33 UTC
Pull block layer updates from Jens Axboe: "I've got a few bits pending for 3.8 final, that I better get sent out. It's all been sitting for a while, I consider it safe. It contains: - Two bug fixes for mtip32xx, fixing a driver hang and a crash. - A few-liner protocol error fix for drbd. - A few fixes for the xen block front/back driver, fixing a potential data corruption issue. - A race fix for disk_clear_events(), causing spurious warnings. Out of the Chrome OS base. - A deadlock fix for disk_clear_events(), moving it to the a unfreezable workqueue. Also from the Chrome OS base." * 'for-linus' of git://git.kernel.dk/linux-block: drbd: fix potential protocol error and resulting disconnect/reconnect mtip32xx: fix for crash when the device surprise removed during rebuild mtip32xx: fix for driver hang after a command timeout block: prevent race/cleanup block: remove deadlock in disk_clear_events xen-blkfront: handle bvecs with partial data llist/xen-blkfront: implement safe version of llist_for_each_entry xen-blkback: implement safe iterator for the list of persistent grants
Tip revision: 2110cf029a67237db572299bb51e0de9e3e3d4dd authored by Linus Torvalds on 06 February 2013, 21:38:33 UTC
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Tip revision: 2110cf0
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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