cpuset: remove on stack cpumask_t in cpuset_can_attach()

Impact: reduce stack usage

Just use cs->cpus_allowed, and no need to allocate a cpumask_var_t.

Signed-off-by: Li Zefan <lizf@cn.fujistu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Mike Travis <travis@sgi.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 41c2343..afa29cf 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1311,20 +1311,19 @@ static int cpuset_can_attach(struct cgroup_subsys *ss,
                             struct cgroup *cont, struct task_struct *tsk)
 {
        struct cpuset *cs = cgroup_cs(cont);
+       int ret = 0;
 
        if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
                return -ENOSPC;
-       if (tsk->flags & PF_THREAD_BOUND) {
-               cpumask_t mask;
 
+       if (tsk->flags & PF_THREAD_BOUND) {
                mutex_lock(&callback_mutex);
-               mask = cs->cpus_allowed;
+               if (!cpus_equal(tsk->cpus_allowed, cs->cpus_allowed))
+                       ret = -EINVAL;
                mutex_unlock(&callback_mutex);
-               if (!cpus_equal(tsk->cpus_allowed, mask))
-                       return -EINVAL;
        }
 
-       return security_task_setscheduler(tsk, 0, NULL);
+       return ret < 0 ? ret : security_task_setscheduler(tsk, 0, NULL);
 }
 
 static void cpuset_attach(struct cgroup_subsys *ss,