cpuset: refactor out validate_partition

Refactor the validate_partition function to handle cpuset partition
validation when modifying cpuset.cpus. This refactoring also makes the
function reusable for handling cpuset.cpus.exclusive updates in subsequent
patches.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 8cb4d8fcf10cf262315caf6a0cd5cafe3d37f706..2e963e2ef8eae8a6bef3acfd74f864df0ed4660f 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2387,6 +2387,37 @@ static int parse_cpuset_cpulist(const char *buf, struct cpumask *out_mask)
        return 0;
 }
 
+/**
+ * validate_partition - Validate a cpuset partition configuration
+ * @cs: The cpuset to validate
+ * @trialcs: The trial cpuset containing proposed configuration changes
+ *
+ * If any validation check fails, the appropriate error code is set in the
+ * cpuset's prs_err field.
+ *
+ * Return: PRS error code (0 if valid, non-zero error code if invalid)
+ */
+static enum prs_errcode validate_partition(struct cpuset *cs, struct cpuset *trialcs)
+{
+       struct cpuset *parent = parent_cs(cs);
+
+       if (cs_is_member(trialcs))
+               return PERR_NONE;
+
+       if (cpumask_empty(trialcs->effective_xcpus))
+               return PERR_INVCPUS;
+
+       if (prstate_housekeeping_conflict(trialcs->partition_root_state,
+                                         trialcs->effective_xcpus))
+               return PERR_HKEEPING;
+
+       if (tasks_nocpu_error(parent, cs, trialcs->effective_xcpus))
+               return PERR_NOCPUS;
+
+       return PERR_NONE;
+}
+
+
 /**
  * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
  * @cs: the cpuset to consider
@@ -2402,6 +2433,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
        bool invalidate = false;
        bool force = false;
        int old_prs = cs->partition_root_state;
+       enum prs_errcode prs_err;
 
        retval = parse_cpuset_cpulist(buf, trialcs->cpus_allowed);
        if (retval < 0)
@@ -2416,18 +2448,10 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 
        compute_trialcs_excpus(trialcs, cs);
 
-       if (old_prs) {
-               if (is_partition_valid(cs) &&
-                   cpumask_empty(trialcs->effective_xcpus)) {
-                       invalidate = true;
-                       cs->prs_err = PERR_INVCPUS;
-               } else if (prstate_housekeeping_conflict(old_prs, trialcs->effective_xcpus)) {
-                       invalidate = true;
-                       cs->prs_err = PERR_HKEEPING;
-               } else if (tasks_nocpu_error(parent, cs, trialcs->effective_xcpus)) {
-                       invalidate = true;
-                       cs->prs_err = PERR_NOCPUS;
-               }
+       prs_err = validate_partition(cs, trialcs);
+       if (prs_err) {
+               invalidate = true;
+               cs->prs_err = prs_err;
        }
 
        /*