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v4.6
  1/*
  2 * mm/percpu-vm.c - vmalloc area based chunk allocation
  3 *
  4 * Copyright (C) 2010		SUSE Linux Products GmbH
  5 * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
  6 *
  7 * This file is released under the GPLv2.
  8 *
  9 * Chunks are mapped into vmalloc areas and populated page by page.
 10 * This is the default chunk allocator.
 11 */
 12
 13static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
 14				    unsigned int cpu, int page_idx)
 15{
 16	/* must not be used on pre-mapped chunk */
 17	WARN_ON(chunk->immutable);
 18
 19	return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 20}
 21
 22/**
 23 * pcpu_get_pages - get temp pages array
 24 * @chunk: chunk of interest
 25 *
 26 * Returns pointer to array of pointers to struct page which can be indexed
 27 * with pcpu_page_idx().  Note that there is only one array and accesses
 28 * should be serialized by pcpu_alloc_mutex.
 29 *
 30 * RETURNS:
 31 * Pointer to temp pages array on success.
 32 */
 33static struct page **pcpu_get_pages(struct pcpu_chunk *chunk_alloc)
 34{
 35	static struct page **pages;
 36	size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
 37
 38	lockdep_assert_held(&pcpu_alloc_mutex);
 39
 40	if (!pages)
 41		pages = pcpu_mem_zalloc(pages_size);
 42	return pages;
 43}
 44
 45/**
 46 * pcpu_free_pages - free pages which were allocated for @chunk
 47 * @chunk: chunk pages were allocated for
 48 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
 49 * @page_start: page index of the first page to be freed
 50 * @page_end: page index of the last page to be freed + 1
 51 *
 52 * Free pages [@page_start and @page_end) in @pages for all units.
 53 * The pages were allocated for @chunk.
 54 */
 55static void pcpu_free_pages(struct pcpu_chunk *chunk,
 56			    struct page **pages, int page_start, int page_end)
 57{
 58	unsigned int cpu;
 59	int i;
 60
 61	for_each_possible_cpu(cpu) {
 62		for (i = page_start; i < page_end; i++) {
 63			struct page *page = pages[pcpu_page_idx(cpu, i)];
 64
 65			if (page)
 66				__free_page(page);
 67		}
 68	}
 69}
 70
 71/**
 72 * pcpu_alloc_pages - allocates pages for @chunk
 73 * @chunk: target chunk
 74 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
 75 * @page_start: page index of the first page to be allocated
 76 * @page_end: page index of the last page to be allocated + 1
 
 77 *
 78 * Allocate pages [@page_start,@page_end) into @pages for all units.
 79 * The allocation is for @chunk.  Percpu core doesn't care about the
 80 * content of @pages and will pass it verbatim to pcpu_map_pages().
 81 */
 82static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
 83			    struct page **pages, int page_start, int page_end)
 
 84{
 85	const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
 86	unsigned int cpu, tcpu;
 87	int i;
 88
 
 
 89	for_each_possible_cpu(cpu) {
 90		for (i = page_start; i < page_end; i++) {
 91			struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
 92
 93			*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
 94			if (!*pagep)
 95				goto err;
 96		}
 97	}
 98	return 0;
 99
100err:
101	while (--i >= page_start)
102		__free_page(pages[pcpu_page_idx(cpu, i)]);
103
104	for_each_possible_cpu(tcpu) {
105		if (tcpu == cpu)
106			break;
107		for (i = page_start; i < page_end; i++)
108			__free_page(pages[pcpu_page_idx(tcpu, i)]);
109	}
110	return -ENOMEM;
111}
112
113/**
114 * pcpu_pre_unmap_flush - flush cache prior to unmapping
115 * @chunk: chunk the regions to be flushed belongs to
116 * @page_start: page index of the first page to be flushed
117 * @page_end: page index of the last page to be flushed + 1
118 *
119 * Pages in [@page_start,@page_end) of @chunk are about to be
120 * unmapped.  Flush cache.  As each flushing trial can be very
121 * expensive, issue flush on the whole region at once rather than
122 * doing it for each cpu.  This could be an overkill but is more
123 * scalable.
124 */
125static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
126				 int page_start, int page_end)
127{
128	flush_cache_vunmap(
129		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
130		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
131}
132
133static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
134{
135	unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
136}
137
138/**
139 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
140 * @chunk: chunk of interest
141 * @pages: pages array which can be used to pass information to free
142 * @page_start: page index of the first page to unmap
143 * @page_end: page index of the last page to unmap + 1
144 *
145 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
146 * Corresponding elements in @pages were cleared by the caller and can
147 * be used to carry information to pcpu_free_pages() which will be
148 * called after all unmaps are finished.  The caller should call
149 * proper pre/post flush functions.
150 */
151static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
152			     struct page **pages, int page_start, int page_end)
153{
154	unsigned int cpu;
155	int i;
156
157	for_each_possible_cpu(cpu) {
158		for (i = page_start; i < page_end; i++) {
159			struct page *page;
160
161			page = pcpu_chunk_page(chunk, cpu, i);
162			WARN_ON(!page);
163			pages[pcpu_page_idx(cpu, i)] = page;
164		}
165		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
166				   page_end - page_start);
167	}
168}
169
170/**
171 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
172 * @chunk: pcpu_chunk the regions to be flushed belong to
173 * @page_start: page index of the first page to be flushed
174 * @page_end: page index of the last page to be flushed + 1
175 *
176 * Pages [@page_start,@page_end) of @chunk have been unmapped.  Flush
177 * TLB for the regions.  This can be skipped if the area is to be
178 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
179 *
180 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
181 * for the whole region.
182 */
183static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
184				      int page_start, int page_end)
185{
186	flush_tlb_kernel_range(
187		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
188		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
189}
190
191static int __pcpu_map_pages(unsigned long addr, struct page **pages,
192			    int nr_pages)
193{
194	return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
195					PAGE_KERNEL, pages);
196}
197
198/**
199 * pcpu_map_pages - map pages into a pcpu_chunk
200 * @chunk: chunk of interest
201 * @pages: pages array containing pages to be mapped
202 * @page_start: page index of the first page to map
203 * @page_end: page index of the last page to map + 1
204 *
205 * For each cpu, map pages [@page_start,@page_end) into @chunk.  The
206 * caller is responsible for calling pcpu_post_map_flush() after all
207 * mappings are complete.
208 *
209 * This function is responsible for setting up whatever is necessary for
210 * reverse lookup (addr -> chunk).
211 */
212static int pcpu_map_pages(struct pcpu_chunk *chunk,
213			  struct page **pages, int page_start, int page_end)
214{
215	unsigned int cpu, tcpu;
216	int i, err;
217
218	for_each_possible_cpu(cpu) {
219		err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
220				       &pages[pcpu_page_idx(cpu, page_start)],
221				       page_end - page_start);
222		if (err < 0)
223			goto err;
224
225		for (i = page_start; i < page_end; i++)
226			pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
227					    chunk);
228	}
229	return 0;
230err:
231	for_each_possible_cpu(tcpu) {
232		if (tcpu == cpu)
233			break;
234		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
235				   page_end - page_start);
236	}
237	pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
238	return err;
239}
240
241/**
242 * pcpu_post_map_flush - flush cache after mapping
243 * @chunk: pcpu_chunk the regions to be flushed belong to
244 * @page_start: page index of the first page to be flushed
245 * @page_end: page index of the last page to be flushed + 1
246 *
247 * Pages [@page_start,@page_end) of @chunk have been mapped.  Flush
248 * cache.
249 *
250 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
251 * for the whole region.
252 */
253static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
254				int page_start, int page_end)
255{
256	flush_cache_vmap(
257		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
258		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
259}
260
261/**
262 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
263 * @chunk: chunk of interest
264 * @page_start: the start page
265 * @page_end: the end page
 
266 *
267 * For each cpu, populate and map pages [@page_start,@page_end) into
268 * @chunk.
269 *
270 * CONTEXT:
271 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
272 */
273static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
274			       int page_start, int page_end)
275{
276	struct page **pages;
277
278	pages = pcpu_get_pages(chunk);
279	if (!pages)
280		return -ENOMEM;
281
282	if (pcpu_alloc_pages(chunk, pages, page_start, page_end))
283		return -ENOMEM;
284
285	if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
286		pcpu_free_pages(chunk, pages, page_start, page_end);
287		return -ENOMEM;
288	}
289	pcpu_post_map_flush(chunk, page_start, page_end);
290
291	return 0;
292}
293
294/**
295 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
296 * @chunk: chunk to depopulate
297 * @page_start: the start page
298 * @page_end: the end page
299 *
300 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
301 * from @chunk.
302 *
303 * CONTEXT:
304 * pcpu_alloc_mutex.
305 */
306static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
307				  int page_start, int page_end)
308{
309	struct page **pages;
310
311	/*
312	 * If control reaches here, there must have been at least one
313	 * successful population attempt so the temp pages array must
314	 * be available now.
315	 */
316	pages = pcpu_get_pages(chunk);
317	BUG_ON(!pages);
318
319	/* unmap and free */
320	pcpu_pre_unmap_flush(chunk, page_start, page_end);
321
322	pcpu_unmap_pages(chunk, pages, page_start, page_end);
323
324	/* no need to flush tlb, vmalloc will handle it lazily */
325
326	pcpu_free_pages(chunk, pages, page_start, page_end);
327}
328
329static struct pcpu_chunk *pcpu_create_chunk(void)
330{
331	struct pcpu_chunk *chunk;
332	struct vm_struct **vms;
333
334	chunk = pcpu_alloc_chunk();
335	if (!chunk)
336		return NULL;
337
338	vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
339				pcpu_nr_groups, pcpu_atom_size);
340	if (!vms) {
341		pcpu_free_chunk(chunk);
342		return NULL;
343	}
344
345	chunk->data = vms;
346	chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
 
 
 
 
347	return chunk;
348}
349
350static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
351{
352	if (chunk && chunk->data)
 
 
 
 
 
 
353		pcpu_free_vm_areas(chunk->data, pcpu_nr_groups);
354	pcpu_free_chunk(chunk);
355}
356
357static struct page *pcpu_addr_to_page(void *addr)
358{
359	return vmalloc_to_page(addr);
360}
361
362static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
363{
364	/* no extra restriction */
365	return 0;
366}
v4.17
  1/*
  2 * mm/percpu-vm.c - vmalloc area based chunk allocation
  3 *
  4 * Copyright (C) 2010		SUSE Linux Products GmbH
  5 * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
  6 *
  7 * This file is released under the GPLv2.
  8 *
  9 * Chunks are mapped into vmalloc areas and populated page by page.
 10 * This is the default chunk allocator.
 11 */
 12
 13static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
 14				    unsigned int cpu, int page_idx)
 15{
 16	/* must not be used on pre-mapped chunk */
 17	WARN_ON(chunk->immutable);
 18
 19	return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 20}
 21
 22/**
 23 * pcpu_get_pages - get temp pages array
 
 24 *
 25 * Returns pointer to array of pointers to struct page which can be indexed
 26 * with pcpu_page_idx().  Note that there is only one array and accesses
 27 * should be serialized by pcpu_alloc_mutex.
 28 *
 29 * RETURNS:
 30 * Pointer to temp pages array on success.
 31 */
 32static struct page **pcpu_get_pages(void)
 33{
 34	static struct page **pages;
 35	size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
 36
 37	lockdep_assert_held(&pcpu_alloc_mutex);
 38
 39	if (!pages)
 40		pages = pcpu_mem_zalloc(pages_size, GFP_KERNEL);
 41	return pages;
 42}
 43
 44/**
 45 * pcpu_free_pages - free pages which were allocated for @chunk
 46 * @chunk: chunk pages were allocated for
 47 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
 48 * @page_start: page index of the first page to be freed
 49 * @page_end: page index of the last page to be freed + 1
 50 *
 51 * Free pages [@page_start and @page_end) in @pages for all units.
 52 * The pages were allocated for @chunk.
 53 */
 54static void pcpu_free_pages(struct pcpu_chunk *chunk,
 55			    struct page **pages, int page_start, int page_end)
 56{
 57	unsigned int cpu;
 58	int i;
 59
 60	for_each_possible_cpu(cpu) {
 61		for (i = page_start; i < page_end; i++) {
 62			struct page *page = pages[pcpu_page_idx(cpu, i)];
 63
 64			if (page)
 65				__free_page(page);
 66		}
 67	}
 68}
 69
 70/**
 71 * pcpu_alloc_pages - allocates pages for @chunk
 72 * @chunk: target chunk
 73 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
 74 * @page_start: page index of the first page to be allocated
 75 * @page_end: page index of the last page to be allocated + 1
 76 * @gfp: allocation flags passed to the underlying allocator
 77 *
 78 * Allocate pages [@page_start,@page_end) into @pages for all units.
 79 * The allocation is for @chunk.  Percpu core doesn't care about the
 80 * content of @pages and will pass it verbatim to pcpu_map_pages().
 81 */
 82static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
 83			    struct page **pages, int page_start, int page_end,
 84			    gfp_t gfp)
 85{
 
 86	unsigned int cpu, tcpu;
 87	int i;
 88
 89	gfp |= __GFP_HIGHMEM;
 90
 91	for_each_possible_cpu(cpu) {
 92		for (i = page_start; i < page_end; i++) {
 93			struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
 94
 95			*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
 96			if (!*pagep)
 97				goto err;
 98		}
 99	}
100	return 0;
101
102err:
103	while (--i >= page_start)
104		__free_page(pages[pcpu_page_idx(cpu, i)]);
105
106	for_each_possible_cpu(tcpu) {
107		if (tcpu == cpu)
108			break;
109		for (i = page_start; i < page_end; i++)
110			__free_page(pages[pcpu_page_idx(tcpu, i)]);
111	}
112	return -ENOMEM;
113}
114
115/**
116 * pcpu_pre_unmap_flush - flush cache prior to unmapping
117 * @chunk: chunk the regions to be flushed belongs to
118 * @page_start: page index of the first page to be flushed
119 * @page_end: page index of the last page to be flushed + 1
120 *
121 * Pages in [@page_start,@page_end) of @chunk are about to be
122 * unmapped.  Flush cache.  As each flushing trial can be very
123 * expensive, issue flush on the whole region at once rather than
124 * doing it for each cpu.  This could be an overkill but is more
125 * scalable.
126 */
127static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
128				 int page_start, int page_end)
129{
130	flush_cache_vunmap(
131		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
132		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
133}
134
135static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
136{
137	unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
138}
139
140/**
141 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
142 * @chunk: chunk of interest
143 * @pages: pages array which can be used to pass information to free
144 * @page_start: page index of the first page to unmap
145 * @page_end: page index of the last page to unmap + 1
146 *
147 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
148 * Corresponding elements in @pages were cleared by the caller and can
149 * be used to carry information to pcpu_free_pages() which will be
150 * called after all unmaps are finished.  The caller should call
151 * proper pre/post flush functions.
152 */
153static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
154			     struct page **pages, int page_start, int page_end)
155{
156	unsigned int cpu;
157	int i;
158
159	for_each_possible_cpu(cpu) {
160		for (i = page_start; i < page_end; i++) {
161			struct page *page;
162
163			page = pcpu_chunk_page(chunk, cpu, i);
164			WARN_ON(!page);
165			pages[pcpu_page_idx(cpu, i)] = page;
166		}
167		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
168				   page_end - page_start);
169	}
170}
171
172/**
173 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
174 * @chunk: pcpu_chunk the regions to be flushed belong to
175 * @page_start: page index of the first page to be flushed
176 * @page_end: page index of the last page to be flushed + 1
177 *
178 * Pages [@page_start,@page_end) of @chunk have been unmapped.  Flush
179 * TLB for the regions.  This can be skipped if the area is to be
180 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
181 *
182 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
183 * for the whole region.
184 */
185static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
186				      int page_start, int page_end)
187{
188	flush_tlb_kernel_range(
189		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
190		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
191}
192
193static int __pcpu_map_pages(unsigned long addr, struct page **pages,
194			    int nr_pages)
195{
196	return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
197					PAGE_KERNEL, pages);
198}
199
200/**
201 * pcpu_map_pages - map pages into a pcpu_chunk
202 * @chunk: chunk of interest
203 * @pages: pages array containing pages to be mapped
204 * @page_start: page index of the first page to map
205 * @page_end: page index of the last page to map + 1
206 *
207 * For each cpu, map pages [@page_start,@page_end) into @chunk.  The
208 * caller is responsible for calling pcpu_post_map_flush() after all
209 * mappings are complete.
210 *
211 * This function is responsible for setting up whatever is necessary for
212 * reverse lookup (addr -> chunk).
213 */
214static int pcpu_map_pages(struct pcpu_chunk *chunk,
215			  struct page **pages, int page_start, int page_end)
216{
217	unsigned int cpu, tcpu;
218	int i, err;
219
220	for_each_possible_cpu(cpu) {
221		err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
222				       &pages[pcpu_page_idx(cpu, page_start)],
223				       page_end - page_start);
224		if (err < 0)
225			goto err;
226
227		for (i = page_start; i < page_end; i++)
228			pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
229					    chunk);
230	}
231	return 0;
232err:
233	for_each_possible_cpu(tcpu) {
234		if (tcpu == cpu)
235			break;
236		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
237				   page_end - page_start);
238	}
239	pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
240	return err;
241}
242
243/**
244 * pcpu_post_map_flush - flush cache after mapping
245 * @chunk: pcpu_chunk the regions to be flushed belong to
246 * @page_start: page index of the first page to be flushed
247 * @page_end: page index of the last page to be flushed + 1
248 *
249 * Pages [@page_start,@page_end) of @chunk have been mapped.  Flush
250 * cache.
251 *
252 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
253 * for the whole region.
254 */
255static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
256				int page_start, int page_end)
257{
258	flush_cache_vmap(
259		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
260		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
261}
262
263/**
264 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
265 * @chunk: chunk of interest
266 * @page_start: the start page
267 * @page_end: the end page
268 * @gfp: allocation flags passed to the underlying memory allocator
269 *
270 * For each cpu, populate and map pages [@page_start,@page_end) into
271 * @chunk.
272 *
273 * CONTEXT:
274 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
275 */
276static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
277			       int page_start, int page_end, gfp_t gfp)
278{
279	struct page **pages;
280
281	pages = pcpu_get_pages();
282	if (!pages)
283		return -ENOMEM;
284
285	if (pcpu_alloc_pages(chunk, pages, page_start, page_end, gfp))
286		return -ENOMEM;
287
288	if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
289		pcpu_free_pages(chunk, pages, page_start, page_end);
290		return -ENOMEM;
291	}
292	pcpu_post_map_flush(chunk, page_start, page_end);
293
294	return 0;
295}
296
297/**
298 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
299 * @chunk: chunk to depopulate
300 * @page_start: the start page
301 * @page_end: the end page
302 *
303 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
304 * from @chunk.
305 *
306 * CONTEXT:
307 * pcpu_alloc_mutex.
308 */
309static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
310				  int page_start, int page_end)
311{
312	struct page **pages;
313
314	/*
315	 * If control reaches here, there must have been at least one
316	 * successful population attempt so the temp pages array must
317	 * be available now.
318	 */
319	pages = pcpu_get_pages();
320	BUG_ON(!pages);
321
322	/* unmap and free */
323	pcpu_pre_unmap_flush(chunk, page_start, page_end);
324
325	pcpu_unmap_pages(chunk, pages, page_start, page_end);
326
327	/* no need to flush tlb, vmalloc will handle it lazily */
328
329	pcpu_free_pages(chunk, pages, page_start, page_end);
330}
331
332static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp)
333{
334	struct pcpu_chunk *chunk;
335	struct vm_struct **vms;
336
337	chunk = pcpu_alloc_chunk(gfp);
338	if (!chunk)
339		return NULL;
340
341	vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
342				pcpu_nr_groups, pcpu_atom_size);
343	if (!vms) {
344		pcpu_free_chunk(chunk);
345		return NULL;
346	}
347
348	chunk->data = vms;
349	chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
350
351	pcpu_stats_chunk_alloc();
352	trace_percpu_create_chunk(chunk->base_addr);
353
354	return chunk;
355}
356
357static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
358{
359	if (!chunk)
360		return;
361
362	pcpu_stats_chunk_dealloc();
363	trace_percpu_destroy_chunk(chunk->base_addr);
364
365	if (chunk->data)
366		pcpu_free_vm_areas(chunk->data, pcpu_nr_groups);
367	pcpu_free_chunk(chunk);
368}
369
370static struct page *pcpu_addr_to_page(void *addr)
371{
372	return vmalloc_to_page(addr);
373}
374
375static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
376{
377	/* no extra restriction */
378	return 0;
379}