1 files changed, 20 insertions, 30 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 203ca52e78dd..64ad59cfad9b 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -488,6 +488,14 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
                         return -EINVAL;
         }
 
+        /* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */
+        if (cgroup_task_count(cur->css.cgroup)) {
+                if (cpus_empty(trial->cpus_allowed) ||
+                    nodes_empty(trial->mems_allowed)) {
+                        return -ENOSPC;
+                }
+        }
+
         return 0;
 }
 
@@ -710,11 +718,13 @@ static int update_cpumask(struct cpuset *cs, char *buf)
         trialcs = *cs;
 
         /*
-         * 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.
+         * An empty cpus_allowed is ok iff there are no tasks in the cpuset.
+         * Since cpulist_parse() fails on an empty mask, we special case
+         * that parsing.  The validate_change() call ensures that cpusets
+         * with tasks have cpus.
          */
-        if (!buf[0] || (buf[0] == '\n' && !buf[1])) {
+        buf = strstrip(buf);
+        if (!*buf) {
                 cpus_clear(trialcs.cpus_allowed);
         } else {
                 retval = cpulist_parse(buf, trialcs.cpus_allowed);
@@ -722,10 +732,6 @@ static int update_cpumask(struct cpuset *cs, char *buf)
                         return retval;
         }
         cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
-        /* cpus_allowed cannot be empty for a cpuset with attached tasks. */
-        if (cgroup_task_count(cs->css.cgroup) &&
-            cpus_empty(trialcs.cpus_allowed))
-                return -ENOSPC;
         retval = validate_change(cs, &trialcs);
         if (retval < 0)
                 return retval;
@@ -830,29 +836,19 @@ static int update_nodemask(struct cpuset *cs, char *buf)
         trialcs = *cs;
 
         /*
-         * 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.
+         * An empty mems_allowed is ok iff there are no tasks in the cpuset.
+         * Since nodelist_parse() fails on an empty mask, we special case
+         * that parsing.  The validate_change() call ensures that cpusets
+         * with tasks have memory.
          */
-        if (!buf[0] || (buf[0] == '\n' && !buf[1])) {
+        buf = strstrip(buf);
+        if (!*buf) {
                 nodes_clear(trialcs.mems_allowed);
         } else {
                 retval = nodelist_parse(buf, trialcs.mems_allowed);
                 if (retval < 0)
                         goto done;
-                if (!nodes_intersects(trialcs.mems_allowed,
-                                                node_states[N_HIGH_MEMORY])) {
-                        /*
-                         * error if only memoryless nodes specified.
-                         */
-                        retval = -ENOSPC;
-                        goto done;
-                }
         }
-        /*
-         * Exclude memoryless nodes.  We know that trialcs.mems_allowed
-         * contains at least one node with memory.
-         */
         nodes_and(trialcs.mems_allowed, trialcs.mems_allowed,
                                                 node_states[N_HIGH_MEMORY]);
         oldmem = cs->mems_allowed;
@@ -860,12 +856,6 @@ static int update_nodemask(struct cpuset *cs, char *buf)
                 retval = 0;             /* Too easy - nothing to do */
                 goto done;
         }
-        /* mems_allowed cannot be empty for a cpuset with attached tasks. */
-        if (cgroup_task_count(cs->css.cgroup) &&
-            nodes_empty(trialcs.mems_allowed)) {
-                retval = -ENOSPC;
-                goto done;
-        }
         retval = validate_change(cs, &trialcs);
         if (retval < 0)
                 goto done;