提交 d359b549 编写于 作者: O Oleg Nesterov 提交者: Linus Torvalds

[PATCH] futex_find_get_task(): don't take tasklist_lock

It is ok to do find_task_by_pid() + get_task_struct() under
rcu_read_lock(), we cand drop tasklist_lock.

Note that testing of ->exit_state is racy with or without tasklist anyway.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 44938af6
......@@ -389,7 +389,7 @@ static struct task_struct * futex_find_get_task(pid_t pid)
{
struct task_struct *p;
read_lock(&tasklist_lock);
rcu_read_lock();
p = find_task_by_pid(pid);
if (!p)
goto out_unlock;
......@@ -403,7 +403,7 @@ static struct task_struct * futex_find_get_task(pid_t pid)
}
get_task_struct(p);
out_unlock:
read_unlock(&tasklist_lock);
rcu_read_unlock();
return p;
}
......
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