From: James Morse <james.morse@arm.com> maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/... --------------------------- get_domain_from_cpu() is a handy helper that both the arch code and resctrl need to use. Rename it resctrl_get_domain_from_cpu() so it gets moved out to /fs, and exported back to the arch code. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- arch/x86/kernel/cpu/resctrl/core.c | 15 +------------- arch/x86/kernel/cpu/resctrl/internal.h | 1 - arch/x86/kernel/cpu/resctrl/monitor.c | 2 +- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 +- include/linux/resctrl.h | 28 ++++++++++++++++++++++++++ 5 files changed, 31 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 786f3c9a7267..6176c163af54 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -355,19 +355,6 @@ cat_wrmsr(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r) wrmsrl(hw_res->msr_base + i, hw_dom->ctrl_val[i]); } -struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r) -{ - struct rdt_domain *d; - - list_for_each_entry(d, &r->domains, list) { - /* Find the domain that contains this CPU */ - if (cpumask_test_cpu(cpu, &d->cpu_mask)) - return d; - } - - return NULL; -} - u32 resctrl_arch_get_num_closid(struct rdt_resource *r) { return resctrl_to_arch_res(r)->num_closid; @@ -381,7 +368,7 @@ void rdt_ctrl_update(void *arg) int cpu = smp_processor_id(); struct rdt_domain *d; - d = get_domain_from_cpu(cpu, r); + d = resctrl_get_domain_from_cpu(cpu, r); if (d) { hw_res->msr_update(d, m, r); return; diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 1d1412d19737..3d40e215b96b 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -475,7 +475,6 @@ int rdt_pseudo_lock_init(void); void rdt_pseudo_lock_release(void); int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp); void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp); -struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r); int closids_supported(void); void closid_free(int closid); int alloc_rmid(u32 closid); diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index fbb2877e317c..91861a54c4d0 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -677,7 +677,7 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm) idx = resctrl_arch_rmid_idx_encode(closid, rmid); pmbm_data = &dom_mbm->mbm_local[idx]; - dom_mba = get_domain_from_cpu(smp_processor_id(), r_mba); + dom_mba = resctrl_get_domain_from_cpu(smp_processor_id(), r_mba); if (!dom_mba) { pr_warn_once("Failure to get domain for MBA update\n"); return; diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index f5ed5089084d..c3336a320375 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -4162,7 +4162,7 @@ void resctrl_offline_cpu(unsigned int cpu) if (!l3->mon_capable) goto out_unlock; - d = get_domain_from_cpu(cpu, l3); + d = resctrl_get_domain_from_cpu(cpu, l3); if (d) { if (resctrl_is_mbm_enabled() && cpu == d->mbm_work_cpu) { cancel_delayed_work(&d->mbm_over); diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index d7850cf6effe..8970dcf0e242 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -2,6 +2,7 @@ #ifndef _RESCTRL_H #define _RESCTRL_H +#include <linux/cpu.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/pid.h> @@ -271,6 +272,33 @@ static inline u32 resctrl_get_config_index(u32 closid, } } +/* + * Caller must be in a RCU read-side critical section, or hold the + * cpuhp read lock to prevent the struct rdt_domain being freed. + */ +static inline struct rdt_domain * +resctrl_get_domain_from_cpu(int cpu, struct rdt_resource *r) +{ + struct rdt_domain *d; + + /* + * Walking r->domains, ensure it can't race with cpuhp. + * Because this is called via IPI by rdt_ctrl_update(), assertions + * about locks this thread holds will lead to false positives. Check + * someone is holding the CPUs lock. + */ + if (IS_ENABLED(CONFIG_LOCKDEP)) + lockdep_is_cpus_held(); + + list_for_each_entry_rcu(d, &r->domains, list) { + /* Find the domain that contains this CPU */ + if (cpumask_test_cpu(cpu, &d->cpu_mask)) + return d; + } + + return NULL; +} + /* * Update the ctrl_val and apply this config right now. * Must be called on one of the domain's CPUs. -- 2.25.1