[PATCH v5 05/12] cpuset: use partition_disable() for remote partition disablement

[Ridong Chen <ridong.chen@linux.dev>]

From: Ridong Chen <chenridong@xiaomi.com>

Now that the partition_disable() helper is available, replace the
existing implementation for remote partition disablement with this
centralized function to unify the disablement logic.

remote_partition_disable() is removed and its callers call
partition_disable() directly. The new partition root state is passed
in by the caller instead of being derived from cs->prs_err, as only the
caller knows which state the partition is going to.

Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 kernel/cgroup/cpuset.c | 57 ++++++------------------------------------
 1 file changed, 8 insertions(+), 49 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 3702e43e95ef..681adcde10e8 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1771,9 +1771,8 @@ static void partition_enable(struct cpuset *cs, struct cpuset *parent,
  * has its state updated. A valid partition under an invalid parent has
  * already given back its CPUs, so only the propagation is done.
  */
-static void __maybe_unused partition_disable(struct cpuset *cs, int new_prs,
-					     enum prs_errcode prs_err,
-					     struct tmpmasks *tmp)
+static void partition_disable(struct cpuset *cs, int new_prs,
+			      enum prs_errcode prs_err, struct tmpmasks *tmp)
 {
 	struct cpuset *parent = is_remote_partition(cs) ? NULL : parent_cs(cs);
 	int old_prs = cs->partition_root_state;
@@ -1923,48 +1922,6 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs,
 	return 0;
 }
 
-/*
- * remote_partition_disable - Remove current cpuset from remote partition list
- * @cs: the cpuset to update
- * @tmp: temporary masks
- *
- * The effective_cpus is also updated.
- *
- * cpuset_mutex must be held by the caller.
- */
-static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp)
-{
-	WARN_ON_ONCE(!is_remote_partition(cs));
-	/*
-	 * When a CPU is offlined, top_cpuset may end up with no available CPUs,
-	 * which should clear subpartitions_cpus. We should not emit a warning for this
-	 * scenario: the hierarchy is updated from top to bottom, so subpartitions_cpus
-	 * may already be cleared when disabling the partition.
-	 */
-	WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus) &&
-		     !cpumask_empty(subpartitions_cpus));
-
-	spin_lock_irq(&callback_lock);
-	cs->remote_partition = false;
-	partition_xcpus_del(cs->partition_root_state, NULL, cs->effective_xcpus);
-	if (cs->prs_err)
-		cs->partition_root_state = -cs->partition_root_state;
-	else
-		cs->partition_root_state = PRS_MEMBER;
-
-	/* effective_xcpus may need to be changed */
-	compute_excpus(cs, cs->effective_xcpus);
-	reset_partition_data(cs);
-	spin_unlock_irq(&callback_lock);
-	cpuset_force_rebuild();
-
-	/*
-	 * Propagate changes in top_cpuset's effective_cpus down the hierarchy.
-	 */
-	cpuset_update_tasks_cpumask(&top_cpuset, tmp->new_cpus);
-	update_sibling_cpumasks(&top_cpuset, NULL, tmp);
-}
-
 /*
  * remote_cpus_update - cpus_exclusive change of remote partition
  * @cs: the cpuset to be updated
@@ -2039,7 +1996,7 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus,
 	return;
 
 invalidate:
-	remote_partition_disable(cs, tmp);
+	partition_disable(cs, -prs, cs->prs_err, tmp);
 }
 
 /**
@@ -2667,7 +2624,8 @@ static void partition_cpus_change(struct cpuset *cs, struct cpuset *trialcs,
 
 	if (is_remote_partition(cs)) {
 		if (trialcs->prs_err)
-			remote_partition_disable(cs, tmp);
+			partition_disable(cs, -cs->partition_root_state,
+					  cs->prs_err, tmp);
 		else
 			remote_cpus_update(cs, trialcs->exclusive_cpus,
 					   trialcs->effective_xcpus, tmp);
@@ -3215,7 +3173,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
 
 	if (disable_partition) {
 		if (is_remote_partition(cs))
-			remote_partition_disable(cs, &tmpmask);
+			partition_disable(cs, PRS_MEMBER, PERR_NONE, &tmpmask);
 		else
 			update_parent_effective_cpumask(cs, partcmd_disable,
 							NULL, &tmpmask);
@@ -4164,7 +4122,8 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
 				       (cpumask_empty(&new_cpus) &&
 					partition_is_populated(cs, NULL)))) {
 		WRITE_ONCE(cs->prs_err, PERR_HOTPLUG);
-		remote_partition_disable(cs, tmp);
+		partition_disable(cs, -cs->partition_root_state, cs->prs_err,
+				  tmp);
 		compute_effective_cpumask(&new_cpus, cs, parent);
 	}
 
-- 
2.34.1