From c6366739804f836ac88474527430d3fd174580eb Mon Sep 17 00:00:00 2001 From: Chen Ridong Date: Wed, 17 Sep 2025 06:04:51 +0000 Subject: [PATCH] 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 Reviewed-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 84 ++++++++++++++++++++++-------------------- 1 file changed, 45 insertions(+), 39 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2e963e2ef8eae..cc3837899d4d1 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -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(); - } - } - rcu_read_unlock(); - retval = 0; + prs_err = validate_partition(cs, trialcs); + if (prs_err) { + trialcs->prs_err = prs_err; + cs->prs_err = prs_err; } - 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 -- 2.47.3