[RFC PATCH -v4 22/22] cpuset: remove unnecessary validation in partition_cpus_change

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

From: Chen Ridong <chenridong@huawei.com>

When user-configured CPUs (including cpuset.cpus and cpuset.cpus.exclusive)
are modified, the partition may either be disabled or updated. Both local
and remote partitions update can fully validate their own validity: if the
validation fails, the partition will be disabled. Therefore, the
validation in partition_cpus_change is redundant and can be removed.

With that, trialcs->prs_err is never set, so remove its error branches
in partition_cpus_change() and its initialization in update_cpumask()
and update_exclusive_cpumask().

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 kernel/cgroup/cpuset.c | 40 +++++-----------------------------------
 1 file changed, 5 insertions(+), 35 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 4fd8b0025a5a..e710e7236922 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2459,43 +2459,15 @@ static int parse_cpuset_cpulist(const char *buf, struct cpumask *out_mask)
 static void partition_cpus_change(struct cpuset *cs, struct cpuset *trialcs,
 				  struct tmpmasks *tmp)
 {
-	enum prs_errcode prs_err;
-	struct cpuset *parent = is_remote_partition(cs) ? NULL : parent_cs(cs);
-
 	if (cs_is_member(cs))
 		return;
 
-	/*
-	 * Check for housekeeping conflict by passing the whole
-	 * effective_xcpus as well as those CPUs that are to be
-	 * removed from cs as delmask.
-	 */
-	if (is_partition_valid(cs))
-		cpumask_andnot(tmp->delmask, cs->effective_xcpus,
-			       trialcs->effective_xcpus);
+	if (is_remote_partition(cs))
+		remote_cpus_update(cs, trialcs->exclusive_cpus,
+				   trialcs->effective_xcpus, tmp);
 	else
-		cpumask_clear(tmp->delmask);
-
-	prs_err = validate_partition(cs, parent, trialcs->partition_root_state,
-				     trialcs->effective_xcpus, tmp->delmask);
-	if (prs_err)
-		trialcs->prs_err = prs_err;
-
-	if (is_remote_partition(cs)) {
-		if (trialcs->prs_err)
-			remote_partition_disable(cs, -cs->partition_root_state,
-						 trialcs->prs_err, tmp);
-		else
-			remote_cpus_update(cs, trialcs->exclusive_cpus,
-					   trialcs->effective_xcpus, tmp);
-	} else {
-		if (trialcs->prs_err)
-			local_partition_disable(cs, -cs->partition_root_state,
-						trialcs->prs_err, tmp);
-		else
-			__local_partition_update(cs, trialcs->exclusive_cpus,
-						 trialcs->effective_xcpus, tmp, false);
-	}
+		__local_partition_update(cs, trialcs->exclusive_cpus,
+					 trialcs->effective_xcpus, tmp, false);
 }
 
 /**
@@ -2521,7 +2493,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 		return 0;
 
 	compute_trialcs_excpus(trialcs, cs);
-	trialcs->prs_err = PERR_NONE;
 
 	retval = validate_change(cs, trialcs);
 	if (retval < 0)
@@ -2597,7 +2568,6 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 	if (alloc_tmpmasks(&tmp))
 		return -ENOMEM;
 
-	trialcs->prs_err = PERR_NONE;
 	partition_cpus_change(cs, trialcs, &tmp);
 
 	spin_lock_irq(&callback_lock);
-- 
2.34.1