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>

1 files changed, 5 insertions, 6 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 41c2343df975..afa29cfc5bbb 100644
--- 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,