[PATCH-next v2 2/2] cgroup/cpuset: Remove CS_CPU_EXCLUSIVE handling code from v2

[Waiman Long <longman@redhat.com>]

As the is_cpu_exclusive() function is only used for DEADLINE shrink
test with v1 there is no need to have the CS_CPU_EXCLUSIVE flag set on
valid partition root anymore. Remove update_partition_exclusive_flag()
and other CS_CPU_EXCLUSIVE flag handling code in cpuset.c.

Signed-off-by: Waiman Long <longman@redhat.com>
---
 kernel/cgroup/cpuset.c | 52 ++++--------------------------------------
 1 file changed, 4 insertions(+), 48 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 104fe10c336d..4a915da37bb3 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1174,25 +1174,6 @@ enum partition_cmd {
 static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
 				    struct tmpmasks *tmp);
 
-/*
- * Update partition exclusive flag
- *
- * Return: 0 if successful, an error code otherwise
- */
-static int update_partition_exclusive_flag(struct cpuset *cs, int new_prs)
-{
-	bool exclusive = (new_prs > PRS_MEMBER);
-
-	if (exclusive && !is_cpu_exclusive(cs)) {
-		if (cpuset_update_flag(CS_CPU_EXCLUSIVE, cs, 1))
-			return PERR_NOTEXCL;
-	} else if (!exclusive && is_cpu_exclusive(cs)) {
-		/* Turning off CS_CPU_EXCLUSIVE will not return error */
-		cpuset_update_flag(CS_CPU_EXCLUSIVE, cs, 0);
-	}
-	return 0;
-}
-
 /*
  * Update partition load balance flag and/or rebuild sched domain
  *
@@ -1248,11 +1229,9 @@ static void reset_partition_data(struct cpuset *cs)
 
 	lockdep_assert_held(&callback_lock);
 
-	if (cpumask_empty(cs->exclusive_cpus)) {
+	if (cpumask_empty(cs->exclusive_cpus))
 		cpumask_clear(cs->effective_xcpus);
-		if (is_cpu_exclusive(cs))
-			clear_bit(CS_CPU_EXCLUSIVE, &cs->flags);
-	}
+
 	if (!cpumask_and(cs->effective_cpus, parent->effective_cpus, cs->cpus_allowed))
 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
 }
@@ -2028,19 +2007,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
 	if (!adding && !deleting && (new_prs == old_prs))
 		return 0;
 
-	/*
-	 * Transitioning between invalid to valid or vice versa may require
-	 * changing CS_CPU_EXCLUSIVE. In the case of partcmd_update,
-	 * validate_change() has already been successfully called and
-	 * CPU lists in cs haven't been updated yet. So defer it to later.
-	 */
-	if ((old_prs != new_prs) && (cmd != partcmd_update))  {
-		int err = update_partition_exclusive_flag(cs, new_prs);
-
-		if (err)
-			return err;
-	}
-
 	/*
 	 * Change the parent's effective_cpus & effective_xcpus (top cpuset
 	 * only).
@@ -2063,9 +2029,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
 
 	spin_unlock_irq(&callback_lock);
 
-	if ((old_prs != new_prs) && (cmd == partcmd_update))
-		update_partition_exclusive_flag(cs, new_prs);
-
 	if (adding || deleting) {
 		cpuset_update_tasks_cpumask(parent, tmp->addmask);
 		update_sibling_cpumasks(parent, cs, tmp);
@@ -2942,10 +2905,6 @@ static int update_prstate(struct cpuset *cs, int new_prs)
 	if (alloc_tmpmasks(&tmpmask))
 		return -ENOMEM;
 
-	err = update_partition_exclusive_flag(cs, new_prs);
-	if (err)
-		goto out;
-
 	if (!old_prs) {
 		/*
 		 * cpus_allowed and exclusive_cpus cannot be both empty.
@@ -3009,13 +2968,10 @@ static int update_prstate(struct cpuset *cs, int new_prs)
 	}
 out:
 	/*
-	 * Make partition invalid & disable CS_CPU_EXCLUSIVE if an error
-	 * happens.
+	 * Make partition invalid if an error happens.
 	 */
-	if (err) {
+	if (err)
 		new_prs = -new_prs;
-		update_partition_exclusive_flag(cs, new_prs);
-	}
 
 	spin_lock_irq(&callback_lock);
 	cs->partition_root_state = new_prs;
-- 
2.55.0