xref: /linux/include/linux/cpuhotplug.h (revision 0be3ff0c) 
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __CPUHOTPLUG_H
3 #define __CPUHOTPLUG_H
4 
5 #include <linux/types.h>
6 
7 /*
8  * CPU-up			CPU-down
9  *
10  * BP		AP		BP		AP
11  *
12  * OFFLINE			OFFLINE
13  *   |				  ^
14  *   v				  |
15  * BRINGUP_CPU->AP_OFFLINE	BRINGUP_CPU  <- AP_IDLE_DEAD (idle thread/play_dead)
16  *		  |				AP_OFFLINE
17  *		  v (IRQ-off)	  ,---------------^
18  *		AP_ONLNE	  | (stop_machine)
19  *		  |		TEARDOWN_CPU <-	AP_ONLINE_IDLE
20  *		  |				  ^
21  *		  v				  |
22  *              AP_ACTIVE			AP_ACTIVE
23  */
24 
25 /*
26  * CPU hotplug states. The state machine invokes the installed state
27  * startup callbacks sequentially from CPUHP_OFFLINE + 1 to CPUHP_ONLINE
28  * during a CPU online operation. During a CPU offline operation the
29  * installed teardown callbacks are invoked in the reverse order from
30  * CPU_ONLINE - 1 down to CPUHP_OFFLINE.
31  *
32  * The state space has three sections: PREPARE, STARTING and ONLINE.
33  *
34  * PREPARE: The callbacks are invoked on a control CPU before the
35  * hotplugged CPU is started up or after the hotplugged CPU has died.
36  *
37  * STARTING: The callbacks are invoked on the hotplugged CPU from the low level
38  * hotplug startup/teardown code with interrupts disabled.
39  *
40  * ONLINE: The callbacks are invoked on the hotplugged CPU from the per CPU
41  * hotplug thread with interrupts and preemption enabled.
42  *
43  * Adding explicit states to this enum is only necessary when:
44  *
45  * 1) The state is within the STARTING section
46  *
47  * 2) The state has ordering constraints vs. other states in the
48  *    same section.
49  *
50  * If neither #1 nor #2 apply, please use the dynamic state space when
51  * setting up a state by using CPUHP_PREPARE_DYN or CPUHP_PREPARE_ONLINE
52  * for the @state argument of the setup function.
53  *
54  * See Documentation/core-api/cpu_hotplug.rst for further information and
55  * examples.
56  */
57 enum cpuhp_state {
58 	CPUHP_INVALID = -1,
59 
60 	/* PREPARE section invoked on a control CPU */
61 	CPUHP_OFFLINE = 0,
62 	CPUHP_CREATE_THREADS,
63 	CPUHP_PERF_PREPARE,
64 	CPUHP_PERF_X86_PREPARE,
65 	CPUHP_PERF_X86_AMD_UNCORE_PREP,
66 	CPUHP_PERF_POWER,
67 	CPUHP_PERF_SUPERH,
68 	CPUHP_X86_HPET_DEAD,
69 	CPUHP_X86_APB_DEAD,
70 	CPUHP_X86_MCE_DEAD,
71 	CPUHP_VIRT_NET_DEAD,
72 	CPUHP_SLUB_DEAD,
73 	CPUHP_DEBUG_OBJ_DEAD,
74 	CPUHP_MM_WRITEBACK_DEAD,
75 	/* Must be after CPUHP_MM_VMSTAT_DEAD */
76 	CPUHP_MM_DEMOTION_DEAD,
77 	CPUHP_MM_VMSTAT_DEAD,
78 	CPUHP_SOFTIRQ_DEAD,
79 	CPUHP_NET_MVNETA_DEAD,
80 	CPUHP_CPUIDLE_DEAD,
81 	CPUHP_ARM64_FPSIMD_DEAD,
82 	CPUHP_ARM_OMAP_WAKE_DEAD,
83 	CPUHP_IRQ_POLL_DEAD,
84 	CPUHP_BLOCK_SOFTIRQ_DEAD,
85 	CPUHP_BIO_DEAD,
86 	CPUHP_ACPI_CPUDRV_DEAD,
87 	CPUHP_S390_PFAULT_DEAD,
88 	CPUHP_BLK_MQ_DEAD,
89 	CPUHP_FS_BUFF_DEAD,
90 	CPUHP_PRINTK_DEAD,
91 	CPUHP_MM_MEMCQ_DEAD,
92 	CPUHP_XFS_DEAD,
93 	CPUHP_PERCPU_CNT_DEAD,
94 	CPUHP_RADIX_DEAD,
95 	CPUHP_PAGE_ALLOC,
96 	CPUHP_NET_DEV_DEAD,
97 	CPUHP_PCI_XGENE_DEAD,
98 	CPUHP_IOMMU_IOVA_DEAD,
99 	CPUHP_LUSTRE_CFS_DEAD,
100 	CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
101 	CPUHP_PADATA_DEAD,
102 	CPUHP_AP_DTPM_CPU_DEAD,
103 	CPUHP_RANDOM_PREPARE,
104 	CPUHP_WORKQUEUE_PREP,
105 	CPUHP_POWER_NUMA_PREPARE,
106 	CPUHP_HRTIMERS_PREPARE,
107 	CPUHP_PROFILE_PREPARE,
108 	CPUHP_X2APIC_PREPARE,
109 	CPUHP_SMPCFD_PREPARE,
110 	CPUHP_RELAY_PREPARE,
111 	CPUHP_SLAB_PREPARE,
112 	CPUHP_MD_RAID5_PREPARE,
113 	CPUHP_RCUTREE_PREP,
114 	CPUHP_CPUIDLE_COUPLED_PREPARE,
115 	CPUHP_POWERPC_PMAC_PREPARE,
116 	CPUHP_POWERPC_MMU_CTX_PREPARE,
117 	CPUHP_XEN_PREPARE,
118 	CPUHP_XEN_EVTCHN_PREPARE,
119 	CPUHP_ARM_SHMOBILE_SCU_PREPARE,
120 	CPUHP_SH_SH3X_PREPARE,
121 	CPUHP_NET_FLOW_PREPARE,
122 	CPUHP_TOPOLOGY_PREPARE,
123 	CPUHP_NET_IUCV_PREPARE,
124 	CPUHP_ARM_BL_PREPARE,
125 	CPUHP_TRACE_RB_PREPARE,
126 	CPUHP_MM_ZS_PREPARE,
127 	CPUHP_MM_ZSWP_MEM_PREPARE,
128 	CPUHP_MM_ZSWP_POOL_PREPARE,
129 	CPUHP_KVM_PPC_BOOK3S_PREPARE,
130 	CPUHP_ZCOMP_PREPARE,
131 	CPUHP_TIMERS_PREPARE,
132 	CPUHP_MIPS_SOC_PREPARE,
133 	CPUHP_BP_PREPARE_DYN,
134 	CPUHP_BP_PREPARE_DYN_END		= CPUHP_BP_PREPARE_DYN + 20,
135 	CPUHP_BRINGUP_CPU,
136 
137 	/*
138 	 * STARTING section invoked on the hotplugged CPU in low level
139 	 * bringup and teardown code.
140 	 */
141 	CPUHP_AP_IDLE_DEAD,
142 	CPUHP_AP_OFFLINE,
143 	CPUHP_AP_SCHED_STARTING,
144 	CPUHP_AP_RCUTREE_DYING,
145 	CPUHP_AP_CPU_PM_STARTING,
146 	CPUHP_AP_IRQ_GIC_STARTING,
147 	CPUHP_AP_IRQ_HIP04_STARTING,
148 	CPUHP_AP_IRQ_APPLE_AIC_STARTING,
149 	CPUHP_AP_IRQ_ARMADA_XP_STARTING,
150 	CPUHP_AP_IRQ_BCM2836_STARTING,
151 	CPUHP_AP_IRQ_MIPS_GIC_STARTING,
152 	CPUHP_AP_IRQ_RISCV_STARTING,
153 	CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
154 	CPUHP_AP_ARM_MVEBU_COHERENCY,
155 	CPUHP_AP_MICROCODE_LOADER,
156 	CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
157 	CPUHP_AP_PERF_X86_STARTING,
158 	CPUHP_AP_PERF_X86_AMD_IBS_STARTING,
159 	CPUHP_AP_PERF_X86_CQM_STARTING,
160 	CPUHP_AP_PERF_X86_CSTATE_STARTING,
161 	CPUHP_AP_PERF_XTENSA_STARTING,
162 	CPUHP_AP_MIPS_OP_LOONGSON3_STARTING,
163 	CPUHP_AP_ARM_SDEI_STARTING,
164 	CPUHP_AP_ARM_VFP_STARTING,
165 	CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
166 	CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
167 	CPUHP_AP_PERF_ARM_ACPI_STARTING,
168 	CPUHP_AP_PERF_ARM_STARTING,
169 	CPUHP_AP_PERF_RISCV_STARTING,
170 	CPUHP_AP_ARM_L2X0_STARTING,
171 	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
172 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
173 	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
174 	CPUHP_AP_JCORE_TIMER_STARTING,
175 	CPUHP_AP_ARM_TWD_STARTING,
176 	CPUHP_AP_QCOM_TIMER_STARTING,
177 	CPUHP_AP_TEGRA_TIMER_STARTING,
178 	CPUHP_AP_ARMADA_TIMER_STARTING,
179 	CPUHP_AP_MARCO_TIMER_STARTING,
180 	CPUHP_AP_MIPS_GIC_TIMER_STARTING,
181 	CPUHP_AP_ARC_TIMER_STARTING,
182 	CPUHP_AP_RISCV_TIMER_STARTING,
183 	CPUHP_AP_CLINT_TIMER_STARTING,
184 	CPUHP_AP_CSKY_TIMER_STARTING,
185 	CPUHP_AP_TI_GP_TIMER_STARTING,
186 	CPUHP_AP_HYPERV_TIMER_STARTING,
187 	CPUHP_AP_KVM_STARTING,
188 	CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
189 	CPUHP_AP_KVM_ARM_VGIC_STARTING,
190 	CPUHP_AP_KVM_ARM_TIMER_STARTING,
191 	/* Must be the last timer callback */
192 	CPUHP_AP_DUMMY_TIMER_STARTING,
193 	CPUHP_AP_ARM_XEN_STARTING,
194 	CPUHP_AP_ARM_CORESIGHT_STARTING,
195 	CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
196 	CPUHP_AP_ARM64_ISNDEP_STARTING,
197 	CPUHP_AP_SMPCFD_DYING,
198 	CPUHP_AP_X86_TBOOT_DYING,
199 	CPUHP_AP_ARM_CACHE_B15_RAC_DYING,
200 	CPUHP_AP_ONLINE,
201 	CPUHP_TEARDOWN_CPU,
202 
203 	/* Online section invoked on the hotplugged CPU from the hotplug thread */
204 	CPUHP_AP_ONLINE_IDLE,
205 	CPUHP_AP_SCHED_WAIT_EMPTY,
206 	CPUHP_AP_SMPBOOT_THREADS,
207 	CPUHP_AP_X86_VDSO_VMA_ONLINE,
208 	CPUHP_AP_IRQ_AFFINITY_ONLINE,
209 	CPUHP_AP_BLK_MQ_ONLINE,
210 	CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
211 	CPUHP_AP_X86_INTEL_EPB_ONLINE,
212 	CPUHP_AP_PERF_ONLINE,
213 	CPUHP_AP_PERF_X86_ONLINE,
214 	CPUHP_AP_PERF_X86_UNCORE_ONLINE,
215 	CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE,
216 	CPUHP_AP_PERF_X86_AMD_POWER_ONLINE,
217 	CPUHP_AP_PERF_X86_RAPL_ONLINE,
218 	CPUHP_AP_PERF_X86_CQM_ONLINE,
219 	CPUHP_AP_PERF_X86_CSTATE_ONLINE,
220 	CPUHP_AP_PERF_X86_IDXD_ONLINE,
221 	CPUHP_AP_PERF_S390_CF_ONLINE,
222 	CPUHP_AP_PERF_S390_SF_ONLINE,
223 	CPUHP_AP_PERF_ARM_CCI_ONLINE,
224 	CPUHP_AP_PERF_ARM_CCN_ONLINE,
225 	CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE,
226 	CPUHP_AP_PERF_ARM_HISI_HHA_ONLINE,
227 	CPUHP_AP_PERF_ARM_HISI_L3_ONLINE,
228 	CPUHP_AP_PERF_ARM_HISI_PA_ONLINE,
229 	CPUHP_AP_PERF_ARM_HISI_SLLC_ONLINE,
230 	CPUHP_AP_PERF_ARM_HISI_PCIE_PMU_ONLINE,
231 	CPUHP_AP_PERF_ARM_L2X0_ONLINE,
232 	CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
233 	CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
234 	CPUHP_AP_PERF_ARM_APM_XGENE_ONLINE,
235 	CPUHP_AP_PERF_ARM_CAVIUM_TX2_UNCORE_ONLINE,
236 	CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE,
237 	CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
238 	CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE,
239 	CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
240 	CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
241 	CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE,
242 	CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
243 	CPUHP_AP_PERF_CSKY_ONLINE,
244 	CPUHP_AP_WATCHDOG_ONLINE,
245 	CPUHP_AP_WORKQUEUE_ONLINE,
246 	CPUHP_AP_RANDOM_ONLINE,
247 	CPUHP_AP_RCUTREE_ONLINE,
248 	CPUHP_AP_BASE_CACHEINFO_ONLINE,
249 	CPUHP_AP_ONLINE_DYN,
250 	CPUHP_AP_ONLINE_DYN_END		= CPUHP_AP_ONLINE_DYN + 30,
251 	/* Must be after CPUHP_AP_ONLINE_DYN for node_states[N_CPU] update */
252 	CPUHP_AP_MM_DEMOTION_ONLINE,
253 	CPUHP_AP_X86_HPET_ONLINE,
254 	CPUHP_AP_X86_KVM_CLK_ONLINE,
255 	CPUHP_AP_ACTIVE,
256 	CPUHP_ONLINE,
257 };
258 
259 int __cpuhp_setup_state(enum cpuhp_state state,	const char *name, bool invoke,
260 			int (*startup)(unsigned int cpu),
261 			int (*teardown)(unsigned int cpu), bool multi_instance);
262 
263 int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, const char *name,
264 				   bool invoke,
265 				   int (*startup)(unsigned int cpu),
266 				   int (*teardown)(unsigned int cpu),
267 				   bool multi_instance);
268 /**
269  * cpuhp_setup_state - Setup hotplug state callbacks with calling the @startup
270  *                     callback
271  * @state:	The state for which the calls are installed
272  * @name:	Name of the callback (will be used in debug output)
273  * @startup:	startup callback function or NULL if not required
274  * @teardown:	teardown callback function or NULL if not required
275  *
276  * Installs the callback functions and invokes the @startup callback on
277  * the online cpus which have already reached the @state.
278  */
279 static inline int cpuhp_setup_state(enum cpuhp_state state,
280 				    const char *name,
281 				    int (*startup)(unsigned int cpu),
282 				    int (*teardown)(unsigned int cpu))
283 {
284 	return __cpuhp_setup_state(state, name, true, startup, teardown, false);
285 }
286 
287 /**
288  * cpuhp_setup_state_cpuslocked - Setup hotplug state callbacks with calling
289  *				  @startup callback from a cpus_read_lock()
290  *				  held region
291  * @state:	The state for which the calls are installed
292  * @name:	Name of the callback (will be used in debug output)
293  * @startup:	startup callback function or NULL if not required
294  * @teardown:	teardown callback function or NULL if not required
295  *
296  * Same as cpuhp_setup_state() except that it must be invoked from within a
297  * cpus_read_lock() held region.
298  */
299 static inline int cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
300 					       const char *name,
301 					       int (*startup)(unsigned int cpu),
302 					       int (*teardown)(unsigned int cpu))
303 {
304 	return __cpuhp_setup_state_cpuslocked(state, name, true, startup,
305 					      teardown, false);
306 }
307 
308 /**
309  * cpuhp_setup_state_nocalls - Setup hotplug state callbacks without calling the
310  *			       @startup callback
311  * @state:	The state for which the calls are installed
312  * @name:	Name of the callback.
313  * @startup:	startup callback function or NULL if not required
314  * @teardown:	teardown callback function or NULL if not required
315  *
316  * Same as cpuhp_setup_state() except that the @startup callback is not
317  * invoked during installation. NOP if SMP=n or HOTPLUG_CPU=n.
318  */
319 static inline int cpuhp_setup_state_nocalls(enum cpuhp_state state,
320 					    const char *name,
321 					    int (*startup)(unsigned int cpu),
322 					    int (*teardown)(unsigned int cpu))
323 {
324 	return __cpuhp_setup_state(state, name, false, startup, teardown,
325 				   false);
326 }
327 
328 /**
329  * cpuhp_setup_state_nocalls_cpuslocked - Setup hotplug state callbacks without
330  *					  invoking the @startup callback from
331  *					  a cpus_read_lock() held region
332  *			       callbacks
333  * @state:	The state for which the calls are installed
334  * @name:	Name of the callback.
335  * @startup:	startup callback function or NULL if not required
336  * @teardown:	teardown callback function or NULL if not required
337  *
338  * Same as cpuhp_setup_state_nocalls() except that it must be invoked from
339  * within a cpus_read_lock() held region.
340  */
341 static inline int cpuhp_setup_state_nocalls_cpuslocked(enum cpuhp_state state,
342 						     const char *name,
343 						     int (*startup)(unsigned int cpu),
344 						     int (*teardown)(unsigned int cpu))
345 {
346 	return __cpuhp_setup_state_cpuslocked(state, name, false, startup,
347 					    teardown, false);
348 }
349 
350 /**
351  * cpuhp_setup_state_multi - Add callbacks for multi state
352  * @state:	The state for which the calls are installed
353  * @name:	Name of the callback.
354  * @startup:	startup callback function or NULL if not required
355  * @teardown:	teardown callback function or NULL if not required
356  *
357  * Sets the internal multi_instance flag and prepares a state to work as a multi
358  * instance callback. No callbacks are invoked at this point. The callbacks are
359  * invoked once an instance for this state are registered via
360  * cpuhp_state_add_instance() or cpuhp_state_add_instance_nocalls()
361  */
362 static inline int cpuhp_setup_state_multi(enum cpuhp_state state,
363 					  const char *name,
364 					  int (*startup)(unsigned int cpu,
365 							 struct hlist_node *node),
366 					  int (*teardown)(unsigned int cpu,
367 							  struct hlist_node *node))
368 {
369 	return __cpuhp_setup_state(state, name, false,
370 				   (void *) startup,
371 				   (void *) teardown, true);
372 }
373 
374 int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
375 			       bool invoke);
376 int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state,
377 					  struct hlist_node *node, bool invoke);
378 
379 /**
380  * cpuhp_state_add_instance - Add an instance for a state and invoke startup
381  *                            callback.
382  * @state:	The state for which the instance is installed
383  * @node:	The node for this individual state.
384  *
385  * Installs the instance for the @state and invokes the registered startup
386  * callback on the online cpus which have already reached the @state. The
387  * @state must have been earlier marked as multi-instance by
388  * cpuhp_setup_state_multi().
389  */
390 static inline int cpuhp_state_add_instance(enum cpuhp_state state,
391 					   struct hlist_node *node)
392 {
393 	return __cpuhp_state_add_instance(state, node, true);
394 }
395 
396 /**
397  * cpuhp_state_add_instance_nocalls - Add an instance for a state without
398  *                                    invoking the startup callback.
399  * @state:	The state for which the instance is installed
400  * @node:	The node for this individual state.
401  *
402  * Installs the instance for the @state. The @state must have been earlier
403  * marked as multi-instance by cpuhp_setup_state_multi. NOP if SMP=n or
404  * HOTPLUG_CPU=n.
405  */
406 static inline int cpuhp_state_add_instance_nocalls(enum cpuhp_state state,
407 						   struct hlist_node *node)
408 {
409 	return __cpuhp_state_add_instance(state, node, false);
410 }
411 
412 /**
413  * cpuhp_state_add_instance_nocalls_cpuslocked - Add an instance for a state
414  *						 without invoking the startup
415  *						 callback from a cpus_read_lock()
416  *						 held region.
417  * @state:	The state for which the instance is installed
418  * @node:	The node for this individual state.
419  *
420  * Same as cpuhp_state_add_instance_nocalls() except that it must be
421  * invoked from within a cpus_read_lock() held region.
422  */
423 static inline int
424 cpuhp_state_add_instance_nocalls_cpuslocked(enum cpuhp_state state,
425 					    struct hlist_node *node)
426 {
427 	return __cpuhp_state_add_instance_cpuslocked(state, node, false);
428 }
429 
430 void __cpuhp_remove_state(enum cpuhp_state state, bool invoke);
431 void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke);
432 
433 /**
434  * cpuhp_remove_state - Remove hotplug state callbacks and invoke the teardown
435  * @state:	The state for which the calls are removed
436  *
437  * Removes the callback functions and invokes the teardown callback on
438  * the online cpus which have already reached the @state.
439  */
440 static inline void cpuhp_remove_state(enum cpuhp_state state)
441 {
442 	__cpuhp_remove_state(state, true);
443 }
444 
445 /**
446  * cpuhp_remove_state_nocalls - Remove hotplug state callbacks without invoking
447  *				the teardown callback
448  * @state:	The state for which the calls are removed
449  */
450 static inline void cpuhp_remove_state_nocalls(enum cpuhp_state state)
451 {
452 	__cpuhp_remove_state(state, false);
453 }
454 
455 /**
456  * cpuhp_remove_state_nocalls_cpuslocked - Remove hotplug state callbacks without invoking
457  *					   teardown from a cpus_read_lock() held region.
458  * @state:	The state for which the calls are removed
459  *
460  * Same as cpuhp_remove_state nocalls() except that it must be invoked
461  * from within a cpus_read_lock() held region.
462  */
463 static inline void cpuhp_remove_state_nocalls_cpuslocked(enum cpuhp_state state)
464 {
465 	__cpuhp_remove_state_cpuslocked(state, false);
466 }
467 
468 /**
469  * cpuhp_remove_multi_state - Remove hotplug multi state callback
470  * @state:	The state for which the calls are removed
471  *
472  * Removes the callback functions from a multi state. This is the reverse of
473  * cpuhp_setup_state_multi(). All instances should have been removed before
474  * invoking this function.
475  */
476 static inline void cpuhp_remove_multi_state(enum cpuhp_state state)
477 {
478 	__cpuhp_remove_state(state, false);
479 }
480 
481 int __cpuhp_state_remove_instance(enum cpuhp_state state,
482 				  struct hlist_node *node, bool invoke);
483 
484 /**
485  * cpuhp_state_remove_instance - Remove hotplug instance from state and invoke
486  *                               the teardown callback
487  * @state:	The state from which the instance is removed
488  * @node:	The node for this individual state.
489  *
490  * Removes the instance and invokes the teardown callback on the online cpus
491  * which have already reached @state.
492  */
493 static inline int cpuhp_state_remove_instance(enum cpuhp_state state,
494 					      struct hlist_node *node)
495 {
496 	return __cpuhp_state_remove_instance(state, node, true);
497 }
498 
499 /**
500  * cpuhp_state_remove_instance_nocalls - Remove hotplug instance from state
501  *					 without invoking the teardown callback
502  * @state:	The state from which the instance is removed
503  * @node:	The node for this individual state.
504  *
505  * Removes the instance without invoking the teardown callback.
506  */
507 static inline int cpuhp_state_remove_instance_nocalls(enum cpuhp_state state,
508 						      struct hlist_node *node)
509 {
510 	return __cpuhp_state_remove_instance(state, node, false);
511 }
512 
513 #ifdef CONFIG_SMP
514 void cpuhp_online_idle(enum cpuhp_state state);
515 #else
516 static inline void cpuhp_online_idle(enum cpuhp_state state) { }
517 #endif
518 
519 #endif
520