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authorOleg Nesterov <oleg@tv-sign.ru>2006-09-29 02:00:55 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-29 09:18:18 -0700
commitd359b549bf3d7f42f0084918a4816ea4572e507c (patch)
treea154a9b1913a459bdaed49c623d39f1e73689295
parent44938af6e08580514abce8bea23ae1c034ea0b1d (diff)
[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: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/futex.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 9d260e838cf..ca8ef11feb6 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -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;
}