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Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull SMP hotplug notifier removal from Thomas Gleixner:
 "This is the final cleanup of the hotplug notifier infrastructure. The
  series has been reintgrated in the last two days because there came a
  new driver using the old infrastructure via the SCSI tree.

  Summary:

   - convert the last leftover drivers utilizing notifiers

   - fixup for a completely broken hotplug user

   - prevent setup of already used states

   - removal of the notifiers

   - treewide cleanup of hotplug state names

   - consolidation of state space

  There is a sphinx based documentation pending, but that needs review
  from the documentation folks"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/armada-xp: Consolidate hotplug state space
  irqchip/gic: Consolidate hotplug state space
  coresight/etm3/4x: Consolidate hotplug state space
  cpu/hotplug: Cleanup state names
  cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions
  staging/lustre/libcfs: Convert to hotplug state machine
  scsi/bnx2i: Convert to hotplug state machine
  scsi/bnx2fc: Convert to hotplug state machine
  cpu/hotplug: Prevent overwriting of callbacks
  x86/msr: Remove bogus cleanup from the error path
  bus: arm-ccn: Prevent hotplug callback leak
  perf/x86/intel/cstate: Prevent hotplug callback leak
  ARM/imx/mmcd: Fix broken cpu hotplug handling
  scsi: qedi: Convert to hotplug state machine
This commit is contained in:
Linus Torvalds
2016-12-25 14:05:56 -08:00
parent 10bbe7599e 008b69e4d5
commit b272f732f8
72 changed files with 311 additions and 692 deletions
Download Patch File Download Diff File Expand all files Collapse all files

235
kernel/cpu.c
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@@ -183,23 +183,16 @@ EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
/*
* The following two APIs (cpu_maps_update_begin/done) must be used when
* attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
* The APIs cpu_notifier_register_begin/done() must be used to protect CPU
* hotplug callback (un)registration performed using __register_cpu_notifier()
* or __unregister_cpu_notifier().
*/
void cpu_maps_update_begin(void)
{
mutex_lock(&cpu_add_remove_lock);
}
EXPORT_SYMBOL(cpu_notifier_register_begin);
void cpu_maps_update_done(void)
{
mutex_unlock(&cpu_add_remove_lock);
}
EXPORT_SYMBOL(cpu_notifier_register_done);
static RAW_NOTIFIER_HEAD(cpu_chain);
/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
* Should always be manipulated under cpu_add_remove_lock
@@ -349,66 +342,7 @@ void cpu_hotplug_enable(void)
EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
#endif /* CONFIG_HOTPLUG_CPU */
/* Need to know about CPUs going up/down? */
int register_cpu_notifier(struct notifier_block *nb)
{
int ret;
cpu_maps_update_begin();
ret = raw_notifier_chain_register(&cpu_chain, nb);
cpu_maps_update_done();
return ret;
}
int __register_cpu_notifier(struct notifier_block *nb)
{
return raw_notifier_chain_register(&cpu_chain, nb);
}
static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call,
int *nr_calls)
{
unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0;
void *hcpu = (void *)(long)cpu;
int ret;
ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call,
nr_calls);
return notifier_to_errno(ret);
}
static int cpu_notify(unsigned long val, unsigned int cpu)
{
return __cpu_notify(val, cpu, -1, NULL);
}
static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
{
BUG_ON(cpu_notify(val, cpu));
}
/* Notifier wrappers for transitioning to state machine */
static int notify_prepare(unsigned int cpu)
{
int nr_calls = 0;
int ret;
ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
if (ret) {
nr_calls--;
printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n",
__func__, cpu);
__cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
}
return ret;
}
static int notify_online(unsigned int cpu)
{
cpu_notify(CPU_ONLINE, cpu);
return 0;
}
static int bringup_wait_for_ap(unsigned int cpu)
{
@@ -433,10 +367,8 @@ static int bringup_cpu(unsigned int cpu)
/* Arch-specific enabling code. */
ret = __cpu_up(cpu, idle);
irq_unlock_sparse();
if (ret) {
cpu_notify(CPU_UP_CANCELED, cpu);
if (ret)
return ret;
}
ret = bringup_wait_for_ap(cpu);
BUG_ON(!cpu_online(cpu));
return ret;
@@ -565,11 +497,6 @@ static void cpuhp_thread_fun(unsigned int cpu)
BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
undo_cpu_down(cpu, st);
/*
* This is a momentary workaround to keep the notifier users
* happy. Will go away once we got rid of the notifiers.
*/
cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
st->rollback = false;
} else {
/* Cannot happen .... */
@@ -659,22 +586,6 @@ void __init cpuhp_threads_init(void)
kthread_unpark(this_cpu_read(cpuhp_state.thread));
}
EXPORT_SYMBOL(register_cpu_notifier);
EXPORT_SYMBOL(__register_cpu_notifier);
void unregister_cpu_notifier(struct notifier_block *nb)
{
cpu_maps_update_begin();
raw_notifier_chain_unregister(&cpu_chain, nb);
cpu_maps_update_done();
}
EXPORT_SYMBOL(unregister_cpu_notifier);
void __unregister_cpu_notifier(struct notifier_block *nb)
{
raw_notifier_chain_unregister(&cpu_chain, nb);
}
EXPORT_SYMBOL(__unregister_cpu_notifier);
#ifdef CONFIG_HOTPLUG_CPU
/**
* clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
@@ -741,20 +652,6 @@ static inline void check_for_tasks(int dead_cpu)
read_unlock(&tasklist_lock);
}
static int notify_down_prepare(unsigned int cpu)
{
int err, nr_calls = 0;
err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
if (err) {
nr_calls--;
__cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
pr_warn("%s: attempt to take down CPU %u failed\n",
__func__, cpu);
}
return err;
}
/* Take this CPU down. */
static int take_cpu_down(void *_param)
{
@@ -833,13 +730,6 @@ static int takedown_cpu(unsigned int cpu)
return 0;
}
static int notify_dead(unsigned int cpu)
{
cpu_notify_nofail(CPU_DEAD, cpu);
check_for_tasks(cpu);
return 0;
}
static void cpuhp_complete_idle_dead(void *arg)
{
struct cpuhp_cpu_state *st = arg;
@@ -863,9 +753,7 @@ void cpuhp_report_idle_dead(void)
}
#else
#define notify_down_prepare NULL
#define takedown_cpu NULL
#define notify_dead NULL
#endif
#ifdef CONFIG_HOTPLUG_CPU
@@ -924,9 +812,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;
out:
cpu_hotplug_done();
/* This post dead nonsense must die */
if (!ret && hasdied)
cpu_notify_nofail(CPU_POST_DEAD, cpu);
return ret;
}
@@ -1291,17 +1176,6 @@ static struct cpuhp_step cpuhp_bp_states[] = {
.startup.single = rcutree_prepare_cpu,
.teardown.single = rcutree_dead_cpu,
},
/*
* Preparatory and dead notifiers. Will be replaced once the notifiers
* are converted to states.
*/
[CPUHP_NOTIFY_PREPARE] = {
.name = "notify:prepare",
.startup.single = notify_prepare,
.teardown.single = notify_dead,
.skip_onerr = true,
.cant_stop = true,
},
/*
* On the tear-down path, timers_dead_cpu() must be invoked
* before blk_mq_queue_reinit_notify() from notify_dead(),
@@ -1391,17 +1265,6 @@ static struct cpuhp_step cpuhp_ap_states[] = {
.startup.single = rcutree_online_cpu,
.teardown.single = rcutree_offline_cpu,
},
/*
* Online/down_prepare notifiers. Will be removed once the notifiers
* are converted to states.
*/
[CPUHP_AP_NOTIFY_ONLINE] = {
.name = "notify:online",
.startup.single = notify_online,
.teardown.single = notify_down_prepare,
.skip_onerr = true,
},
#endif
/*
* The dynamically registered state space is here
@@ -1432,23 +1295,53 @@ 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 +1402,6 @@ 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 +1450,13 @@ 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 +1471,16 @@ 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;
}
ret = cpuhp_store_callbacks(state, name, startup, teardown,
multi_instance);
cpuhp_store_callbacks(state, name, startup, teardown, multi_instance);
if (!invoke || !startup)
if (ret || !invoke || !startup)
goto out;
/*
@@ -1641,7 +1504,11 @@ 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;
}