cpuset: remove on stack cpumask_t in cpuset_sprintf_cpulist()

This patchset converts cpuset to use new cpumask API, and thus
remove on stack cpumask_t to reduce stack usage.

Before:
 # cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t
 21
After:
 # cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t
 0

This patch:

Impact: reduce stack usage

It's safe to call cpulist_scnprintf inside callback_mutex, and thus we can
just remove the cpumask_t and no need to allocate a cpumask_var_t.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.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, 3 insertions, 3 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 6012e326e856..41c2343df975 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1486,13 +1486,13 @@ static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft,
 
 static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
 {
-        cpumask_t mask;
+        int ret;
 
         mutex_lock(&callback_mutex);
-        mask = cs->cpus_allowed;
+        ret = cpulist_scnprintf(page, PAGE_SIZE, &cs->cpus_allowed);
         mutex_unlock(&callback_mutex);
 
-        return cpulist_scnprintf(page, PAGE_SIZE, &mask);
+        return ret;
 }
 
 static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)