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-rw-r--r--kernel/cpu.c96
1 files changed, 50 insertions, 46 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 5339aca811d2..3ff0ea5db371 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1432,23 +1432,53 @@ static int cpuhp_cb_check(enum cpuhp_state state)
return 0;
}
-static void cpuhp_store_callbacks(enum cpuhp_state state,
- const char *name,
- int (*startup)(unsigned int cpu),
- int (*teardown)(unsigned int cpu),
- bool multi_instance)
+/*
+ * Returns a free for dynamic slot assignment of the Online state. The states
+ * are protected by the cpuhp_slot_states mutex and an empty slot is identified
+ * by having no name assigned.
+ */
+static int cpuhp_reserve_state(enum cpuhp_state state)
+{
+ enum cpuhp_state i;
+
+ for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) {
+ if (!cpuhp_ap_states[i].name)
+ return i;
+ }
+ WARN(1, "No more dynamic states available for CPU hotplug\n");
+ return -ENOSPC;
+}
+
+static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name,
+ int (*startup)(unsigned int cpu),
+ int (*teardown)(unsigned int cpu),
+ bool multi_instance)
{
/* (Un)Install the callbacks for further cpu hotplug operations */
struct cpuhp_step *sp;
+ int ret = 0;
mutex_lock(&cpuhp_state_mutex);
+
+ if (state == CPUHP_AP_ONLINE_DYN) {
+ ret = cpuhp_reserve_state(state);
+ if (ret < 0)
+ goto out;
+ state = ret;
+ }
sp = cpuhp_get_step(state);
+ if (name && sp->name) {
+ ret = -EBUSY;
+ goto out;
+ }
sp->startup.single = startup;
sp->teardown.single = teardown;
sp->name = name;
sp->multi_instance = multi_instance;
INIT_HLIST_HEAD(&sp->list);
+out:
mutex_unlock(&cpuhp_state_mutex);
+ return ret;
}
static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
@@ -1509,29 +1539,6 @@ static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state,
}
}
-/*
- * Returns a free for dynamic slot assignment of the Online state. The states
- * are protected by the cpuhp_slot_states mutex and an empty slot is identified
- * by having no name assigned.
- */
-static int cpuhp_reserve_state(enum cpuhp_state state)
-{
- enum cpuhp_state i;
-
- mutex_lock(&cpuhp_state_mutex);
- for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) {
- if (cpuhp_ap_states[i].name)
- continue;
-
- cpuhp_ap_states[i].name = "Reserved";
- mutex_unlock(&cpuhp_state_mutex);
- return i;
- }
- mutex_unlock(&cpuhp_state_mutex);
- WARN(1, "No more dynamic states available for CPU hotplug\n");
- return -ENOSPC;
-}
-
int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
bool invoke)
{
@@ -1580,11 +1587,13 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
/**
* __cpuhp_setup_state - Setup the callbacks for an hotplug machine state
- * @state: The state to setup
- * @invoke: If true, the startup function is invoked for cpus where
- * cpu state >= @state
- * @startup: startup callback function
- * @teardown: teardown callback function
+ * @state: The state to setup
+ * @invoke: If true, the startup function is invoked for cpus where
+ * cpu state >= @state
+ * @startup: startup callback function
+ * @teardown: teardown callback function
+ * @multi_instance: State is set up for multiple instances which get
+ * added afterwards.
*
* Returns:
* On success:
@@ -1599,25 +1608,16 @@ int __cpuhp_setup_state(enum cpuhp_state state,
bool multi_instance)
{
int cpu, ret = 0;
- int dyn_state = 0;
if (cpuhp_cb_check(state) || !name)
return -EINVAL;
get_online_cpus();
- /* currently assignments for the ONLINE state are possible */
- if (state == CPUHP_AP_ONLINE_DYN) {
- dyn_state = 1;
- ret = cpuhp_reserve_state(state);
- if (ret < 0)
- goto out;
- state = ret;
- }
-
- cpuhp_store_callbacks(state, name, startup, teardown, multi_instance);
+ ret = cpuhp_store_callbacks(state, name, startup, teardown,
+ multi_instance);
- if (!invoke || !startup)
+ if (ret || !invoke || !startup)
goto out;
/*
@@ -1641,7 +1641,11 @@ int __cpuhp_setup_state(enum cpuhp_state state,
}
out:
put_online_cpus();
- if (!ret && dyn_state)
+ /*
+ * If the requested state is CPUHP_AP_ONLINE_DYN, return the
+ * dynamically allocated state in case of success.
+ */
+ if (!ret && state == CPUHP_AP_ONLINE_DYN)
return state;
return ret;
}