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cpuset: refactor cpus_allowed_validate_change 

Refactor cpus_allowed_validate_change to handle the special case where
cpuset.cpus can be set even when violating partition sibling CPU
exclusivity rules. This differs from the general validation logic in
validate_change. Add a wrapper function to properly handle this
exceptional case.

The trialcs->prs_err field is cleared before performing validation checks
for both CPU changes and partition errors. If cpus_allowed_validate_change
fails its validation, trialcs->prs_err is set to PERR_NOTEXCL. If partition
validation fails, the specific error code returned by validate_partition
is assigned to trialcs->prs_err.

With the partition validation status now directly available through
trialcs->prs_err, the local boolean variable 'invalidate' becomes
redundant and can be safely removed.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
pull/1354/merge
Chen Ridong 2025-09-17 06:04:51 +00:00 committed by Tejun Heo
parent 7e05981ba3
commit c636673980
1 changed files with 45 additions and 39 deletions
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84
kernel/cgroup/cpuset.c
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@ -2417,6 +2417,42 @@ static enum prs_errcode validate_partition(struct cpuset *cs, struct cpuset *tri
return PERR_NONE;
}
static int cpus_allowed_validate_change(struct cpuset *cs, struct cpuset *trialcs,
struct tmpmasks *tmp)
{
int retval;
struct cpuset *parent = parent_cs(cs);
retval = validate_change(cs, trialcs);
if ((retval == -EINVAL) && cpuset_v2()) {
struct cgroup_subsys_state *css;
struct cpuset *cp;
/*
* The -EINVAL error code indicates that partition sibling
* CPU exclusivity rule has been violated. We still allow
* the cpumask change to proceed while invalidating the
* partition. However, any conflicting sibling partitions
* have to be marked as invalid too.
*/
trialcs->prs_err = PERR_NOTEXCL;
rcu_read_lock();
cpuset_for_each_child(cp, css, parent) {
struct cpumask *xcpus = user_xcpus(trialcs);
if (is_partition_valid(cp) &&
cpumask_intersects(xcpus, cp->effective_xcpus)) {
rcu_read_unlock();
update_parent_effective_cpumask(cp, partcmd_invalidate, NULL, tmp);
rcu_read_lock();
}
}
rcu_read_unlock();
retval = 0;
}
return retval;
}
/**
* update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
@ -2429,8 +2465,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
{
int retval;
struct tmpmasks tmp;
struct cpuset *parent = parent_cs(cs);
bool invalidate = false;
bool force = false;
int old_prs = cs->partition_root_state;
enum prs_errcode prs_err;
@ -2447,12 +2481,10 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
return -ENOMEM;
compute_trialcs_excpus(trialcs, cs);
trialcs->prs_err = PERR_NONE;
prs_err = validate_partition(cs, trialcs);
if (prs_err) {
invalidate = true;
cs->prs_err = prs_err;
}
if (cpus_allowed_validate_change(cs, trialcs, &tmp) < 0)
goto out_free;
/*
* Check all the descendants in update_cpumasks_hier() if
@ -2460,40 +2492,14 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
*/
force = !cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus);
retval = validate_change(cs, trialcs);
if ((retval == -EINVAL) && cpuset_v2()) {
struct cgroup_subsys_state *css;
struct cpuset *cp;
/*
* The -EINVAL error code indicates that partition sibling
* CPU exclusivity rule has been violated. We still allow
* the cpumask change to proceed while invalidating the
* partition. However, any conflicting sibling partitions
* have to be marked as invalid too.
*/
invalidate = true;
rcu_read_lock();
cpuset_for_each_child(cp, css, parent) {
struct cpumask *xcpus = user_xcpus(trialcs);
if (is_partition_valid(cp) &&
cpumask_intersects(xcpus, cp->effective_xcpus)) {
rcu_read_unlock();
update_parent_effective_cpumask(cp, partcmd_invalidate, NULL, &tmp);
rcu_read_lock();
prs_err = validate_partition(cs, trialcs);
if (prs_err) {
trialcs->prs_err = prs_err;
cs->prs_err = prs_err;
}
}
rcu_read_unlock();
retval = 0;
}
if (retval < 0)
goto out_free;
if (is_partition_valid(cs) ||
(is_partition_invalid(cs) && !invalidate)) {
(is_partition_invalid(cs) && !trialcs->prs_err)) {
struct cpumask *xcpus = trialcs->effective_xcpus;
if (cpumask_empty(xcpus) && is_partition_invalid(cs))
@ -2504,7 +2510,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
*/
if (is_remote_partition(cs))
remote_cpus_update(cs, NULL, xcpus, &tmp);
else if (invalidate)
else if (trialcs->prs_err)
update_parent_effective_cpumask(cs, partcmd_invalidate,
NULL, &tmp);
else