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-rw-r--r--kernel/cpuset.c38
1 files changed, 30 insertions, 8 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index e6d002fc7392..88b416dfbc72 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -821,11 +821,22 @@ static int update_cpumask(struct cpuset *cs, char *buf)
return -EACCES;
trialcs = *cs;
- retval = cpulist_parse(buf, trialcs.cpus_allowed);
- if (retval < 0)
- return retval;
+
+ /*
+ * We allow a cpuset's cpus_allowed to be empty; if it has attached
+ * tasks, we'll catch it later when we validate the change and return
+ * -ENOSPC.
+ */
+ if (!buf[0] || (buf[0] == '\n' && !buf[1])) {
+ cpus_clear(trialcs.cpus_allowed);
+ } else {
+ retval = cpulist_parse(buf, trialcs.cpus_allowed);
+ if (retval < 0)
+ return retval;
+ }
cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
- if (cpus_empty(trialcs.cpus_allowed))
+ /* cpus_allowed cannot be empty for a cpuset with attached tasks. */
+ if (atomic_read(&cs->count) && cpus_empty(trialcs.cpus_allowed))
return -ENOSPC;
retval = validate_change(cs, &trialcs);
if (retval < 0)
@@ -918,16 +929,27 @@ static int update_nodemask(struct cpuset *cs, char *buf)
return -EACCES;
trialcs = *cs;
- retval = nodelist_parse(buf, trialcs.mems_allowed);
- if (retval < 0)
- goto done;
+
+ /*
+ * We allow a cpuset's mems_allowed to be empty; if it has attached
+ * tasks, we'll catch it later when we validate the change and return
+ * -ENOSPC.
+ */
+ if (!buf[0] || (buf[0] == '\n' && !buf[1])) {
+ nodes_clear(trialcs.mems_allowed);
+ } else {
+ retval = nodelist_parse(buf, trialcs.mems_allowed);
+ if (retval < 0)
+ goto done;
+ }
nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
oldmem = cs->mems_allowed;
if (nodes_equal(oldmem, trialcs.mems_allowed)) {
retval = 0; /* Too easy - nothing to do */
goto done;
}
- if (nodes_empty(trialcs.mems_allowed)) {
+ /* mems_allowed cannot be empty for a cpuset with attached tasks. */
+ if (atomic_read(&cs->count) && nodes_empty(trialcs.mems_allowed)) {
retval = -ENOSPC;
goto done;
}