cpuset: re-structure update_cpumask() a bit

Check if cpus_allowed is to be changed before calling validate_change().

This won't change any behavior, but later it will allow us to do this:

 # mkdir /cpuset/child
 # echo $$ > /cpuset/child/tasks	/* empty cpuset */
 # echo > /cpuset/child/cpuset.cpus	/* do nothing, won't fail */

Without this patch, the last operation will fail.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2013-06-05 17:15:59 +08:00 committed by Tejun Heo
parent 249cc86db7
commit a73456f37b
1 changed files with 4 additions and 3 deletions

View File

@ -856,14 +856,15 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask))
return -EINVAL;
}
retval = validate_change(cs, trialcs);
if (retval < 0)
return retval;
/* Nothing to do if the cpus didn't change */
if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
return 0;
retval = validate_change(cs, trialcs);
if (retval < 0)
return retval;
retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
if (retval)
return retval;