cpuset: remove unneeded NODEMASK_ALLOC() in cpuset_sprintf_memlist()

It's not necessary to copy cpuset->mems_allowed to a buffer allocated by
NODEMASK_ALLOC().  Just pass it to nodelist_scnprintf().

As spotted by Paul, a side effect is we fix a bug that the function can
return -ENOMEM but the caller doesn't expect negative return value.
Therefore change the return value of cpuset_sprintf_cpulist() and
cpuset_sprintf_memlist() from int to size_t.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.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 e92e981..4683fe7 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1610,34 +1610,26 @@ out:
  * across a page fault.
  */
 
-static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
+static size_t cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
 {
-       int ret;
+       size_t count;
 
        mutex_lock(&callback_mutex);
-       ret = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed);
+       count = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed);
        mutex_unlock(&callback_mutex);
 
-       return ret;
+       return count;
 }
 
-static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
+static size_t cpuset_sprintf_memlist(char *page, struct cpuset *cs)
 {
-       NODEMASK_ALLOC(nodemask_t, mask, GFP_KERNEL);
-       int retval;
-
-       if (mask == NULL)
-               return -ENOMEM;
+       size_t count;
 
        mutex_lock(&callback_mutex);
-       *mask = cs->mems_allowed;
+       count = nodelist_scnprintf(page, PAGE_SIZE, cs->mems_allowed);
        mutex_unlock(&callback_mutex);
 
-       retval = nodelist_scnprintf(page, PAGE_SIZE, *mask);
-
-       NODEMASK_FREE(mask);
-
-       return retval;
+       return count;
 }
 
 static ssize_t cpuset_common_file_read(struct cgroup *cont,