提交 1e50df39 编写于 作者: K KOSAKI Motohiro 提交者: Linus Torvalds

mempolicy: remove tasklist_lock from migrate_pages

Today, tasklist_lock in migrate_pages doesn't protect anything.
rcu_read_lock() provide enough protection from pid hash walk.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 53a7706d
......@@ -1310,16 +1310,13 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
/* Find the mm_struct */
rcu_read_lock();
read_lock(&tasklist_lock);
task = pid ? find_task_by_vpid(pid) : current;
if (!task) {
read_unlock(&tasklist_lock);
rcu_read_unlock();
err = -ESRCH;
goto out;
}
mm = get_task_mm(task);
read_unlock(&tasklist_lock);
rcu_read_unlock();
err = -EINVAL;
......
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