Commit a73456f3 authored Jun 05, 2013 by Li Zefan Committed by Tejun Heo Jun 05, 2013

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>

parent 249cc86d

kernel/cpuset.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -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;