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path: root/arch/x86/kernel/cpu/resctrl/rdtgroup.c
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Diffstat (limited to 'arch/x86/kernel/cpu/resctrl/rdtgroup.c')
-rw-r--r--arch/x86/kernel/cpu/resctrl/rdtgroup.c73
1 files changed, 48 insertions, 25 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index c6274d40b217..93ec829015f1 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -944,14 +944,14 @@ int proc_resctrl_show(struct seq_file *s, struct pid_namespace *ns,
continue;
seq_printf(s, "res:%s%s\n", (rdtg == &rdtgroup_default) ? "/" : "",
- rdtg->kn->name);
+ rdt_kn_name(rdtg->kn));
seq_puts(s, "mon:");
list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
mon.crdtgrp_list) {
if (!resctrl_arch_match_rmid(tsk, crg->mon.parent->closid,
crg->mon.rmid))
continue;
- seq_printf(s, "%s", crg->kn->name);
+ seq_printf(s, "%s", rdt_kn_name(crg->kn));
break;
}
seq_putc(s, '\n');
@@ -984,10 +984,20 @@ static int rdt_last_cmd_status_show(struct kernfs_open_file *of,
return 0;
}
+static void *rdt_kn_parent_priv(struct kernfs_node *kn)
+{
+ /*
+ * The parent pointer is only valid within RCU section since it can be
+ * replaced.
+ */
+ guard(rcu)();
+ return rcu_dereference(kn->__parent)->priv;
+}
+
static int rdt_num_closids_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
seq_printf(seq, "%u\n", s->num_closid);
return 0;
@@ -996,7 +1006,7 @@ static int rdt_num_closids_show(struct kernfs_open_file *of,
static int rdt_default_ctrl_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%x\n", resctrl_get_default_ctrl(r));
@@ -1006,7 +1016,7 @@ static int rdt_default_ctrl_show(struct kernfs_open_file *of,
static int rdt_min_cbm_bits_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%u\n", r->cache.min_cbm_bits);
@@ -1016,7 +1026,7 @@ static int rdt_min_cbm_bits_show(struct kernfs_open_file *of,
static int rdt_shareable_bits_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%x\n", r->cache.shareable_bits);
@@ -1040,7 +1050,7 @@ static int rdt_shareable_bits_show(struct kernfs_open_file *of,
static int rdt_bit_usage_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
/*
* Use unsigned long even though only 32 bits are used to ensure
* test_bit() is used safely.
@@ -1122,7 +1132,7 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of,
static int rdt_min_bw_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%u\n", r->membw.min_bw);
@@ -1132,7 +1142,7 @@ static int rdt_min_bw_show(struct kernfs_open_file *of,
static int rdt_num_rmids_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
seq_printf(seq, "%d\n", r->num_rmid);
@@ -1142,7 +1152,7 @@ static int rdt_num_rmids_show(struct kernfs_open_file *of,
static int rdt_mon_features_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
struct mon_evt *mevt;
list_for_each_entry(mevt, &r->evt_list, list) {
@@ -1157,7 +1167,7 @@ static int rdt_mon_features_show(struct kernfs_open_file *of,
static int rdt_bw_gran_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%u\n", r->membw.bw_gran);
@@ -1167,7 +1177,7 @@ static int rdt_bw_gran_show(struct kernfs_open_file *of,
static int rdt_delay_linear_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%u\n", r->membw.delay_linear);
@@ -1185,7 +1195,7 @@ static int max_threshold_occ_show(struct kernfs_open_file *of,
static int rdt_thread_throttle_mode_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
switch (r->membw.throttle_mode) {
@@ -1259,7 +1269,7 @@ static enum resctrl_conf_type resctrl_peer_type(enum resctrl_conf_type my_type)
static int rdt_has_sparse_bitmasks_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct resctrl_schema *s = of->kn->parent->priv;
+ struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
struct rdt_resource *r = s->res;
seq_printf(seq, "%u\n", r->cache.arch_has_sparse_bitmasks);
@@ -1670,7 +1680,7 @@ static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid
static int mbm_total_bytes_config_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
mbm_config_show(seq, r, QOS_L3_MBM_TOTAL_EVENT_ID);
@@ -1680,7 +1690,7 @@ static int mbm_total_bytes_config_show(struct kernfs_open_file *of,
static int mbm_local_bytes_config_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
- struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
mbm_config_show(seq, r, QOS_L3_MBM_LOCAL_EVENT_ID);
@@ -1787,7 +1797,7 @@ static ssize_t mbm_total_bytes_config_write(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
- struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
int ret;
/* Valid input requires a trailing newline */
@@ -1813,7 +1823,7 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
- struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
int ret;
/* Valid input requires a trailing newline */
@@ -2513,12 +2523,13 @@ static struct rdtgroup *kernfs_to_rdtgroup(struct kernfs_node *kn)
* resource. "info" and its subdirectories don't
* have rdtgroup structures, so return NULL here.
*/
- if (kn == kn_info || kn->parent == kn_info)
+ if (kn == kn_info ||
+ rcu_access_pointer(kn->__parent) == kn_info)
return NULL;
else
return kn->priv;
} else {
- return kn->parent->priv;
+ return rdt_kn_parent_priv(kn);
}
}
@@ -3752,7 +3763,7 @@ out_unlock:
*/
static bool is_mon_groups(struct kernfs_node *kn, const char *name)
{
- return (!strcmp(kn->name, "mon_groups") &&
+ return (!strcmp(rdt_kn_name(kn), "mon_groups") &&
strcmp(name, "mon_groups"));
}
@@ -3867,9 +3878,18 @@ static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
return 0;
}
+static struct kernfs_node *rdt_kn_parent(struct kernfs_node *kn)
+{
+ /*
+ * Valid within the RCU section it was obtained or while rdtgroup_mutex
+ * is held.
+ */
+ return rcu_dereference_check(kn->__parent, lockdep_is_held(&rdtgroup_mutex));
+}
+
static int rdtgroup_rmdir(struct kernfs_node *kn)
{
- struct kernfs_node *parent_kn = kn->parent;
+ struct kernfs_node *parent_kn;
struct rdtgroup *rdtgrp;
cpumask_var_t tmpmask;
int ret = 0;
@@ -3882,6 +3902,7 @@ static int rdtgroup_rmdir(struct kernfs_node *kn)
ret = -EPERM;
goto out;
}
+ parent_kn = rdt_kn_parent(kn);
/*
* If the rdtgroup is a ctrl_mon group and parent directory
@@ -3899,7 +3920,7 @@ static int rdtgroup_rmdir(struct kernfs_node *kn)
ret = rdtgroup_rmdir_ctrl(rdtgrp, tmpmask);
}
} else if (rdtgrp->type == RDTMON_GROUP &&
- is_mon_groups(parent_kn, kn->name)) {
+ is_mon_groups(parent_kn, rdt_kn_name(kn))) {
ret = rdtgroup_rmdir_mon(rdtgrp, tmpmask);
} else {
ret = -EPERM;
@@ -3950,6 +3971,7 @@ static void mongrp_reparent(struct rdtgroup *rdtgrp,
static int rdtgroup_rename(struct kernfs_node *kn,
struct kernfs_node *new_parent, const char *new_name)
{
+ struct kernfs_node *kn_parent;
struct rdtgroup *new_prdtgrp;
struct rdtgroup *rdtgrp;
cpumask_var_t tmpmask;
@@ -3984,8 +4006,9 @@ static int rdtgroup_rename(struct kernfs_node *kn,
goto out;
}
- if (rdtgrp->type != RDTMON_GROUP || !kn->parent ||
- !is_mon_groups(kn->parent, kn->name)) {
+ kn_parent = rdt_kn_parent(kn);
+ if (rdtgrp->type != RDTMON_GROUP || !kn_parent ||
+ !is_mon_groups(kn_parent, rdt_kn_name(kn))) {
rdt_last_cmd_puts("Source must be a MON group\n");
ret = -EPERM;
goto out;
generated by cgit (git 2.34.1) at 2025-05-10 03:19:55 +0000