1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * mm/percpu-vm.c - vmalloc area based chunk allocation
  4 *
  5 * Copyright (C) 2010		SUSE Linux Products GmbH
  6 * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
  7 *
  8 * Chunks are mapped into vmalloc areas and populated page by page.
  9 * This is the default chunk allocator.
 10 */
 11
 12static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
 13				    unsigned int cpu, int page_idx)
 14{
 15	/* must not be used on pre-mapped chunk */
 16	WARN_ON(chunk->immutable);
 17
 18	return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 19}
 20
 21/**
 22 * pcpu_get_pages - get temp pages array
 23 *
 24 * Returns pointer to array of pointers to struct page which can be indexed
 25 * with pcpu_page_idx().  Note that there is only one array and accesses
 26 * should be serialized by pcpu_alloc_mutex.
 27 *
 28 * RETURNS:
 29 * Pointer to temp pages array on success.
 30 */
 31static struct page **pcpu_get_pages(void)
 32{
 33	static struct page **pages;
 34	size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
 35
 36	lockdep_assert_held(&pcpu_alloc_mutex);
 37
 38	if (!pages)
 39		pages = pcpu_mem_zalloc(pages_size, GFP_KERNEL);
 40	return pages;
 41}
 42
 43/**
 44 * pcpu_free_pages - free pages which were allocated for @chunk
 45 * @chunk: chunk pages were allocated for
 46 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
 47 * @page_start: page index of the first page to be freed
 48 * @page_end: page index of the last page to be freed + 1
 49 *
 50 * Free pages [@page_start and @page_end) in @pages for all units.
 51 * The pages were allocated for @chunk.
 52 */
 53static void pcpu_free_pages(struct pcpu_chunk *chunk,
 54			    struct page **pages, int page_start, int page_end)
 55{
 56	unsigned int cpu;
 57	int i;
 58
 59	for_each_possible_cpu(cpu) {
 60		for (i = page_start; i < page_end; i++) {
 61			struct page *page = pages[pcpu_page_idx(cpu, i)];
 62
 63			if (page)
 64				__free_page(page);
 65		}
 66	}
 67}
 68
 69/**
 70 * pcpu_alloc_pages - allocates pages for @chunk
 71 * @chunk: target chunk
 72 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
 73 * @page_start: page index of the first page to be allocated
 74 * @page_end: page index of the last page to be allocated + 1
 75 * @gfp: allocation flags passed to the underlying allocator
 76 *
 77 * Allocate pages [@page_start,@page_end) into @pages for all units.
 78 * The allocation is for @chunk.  Percpu core doesn't care about the
 79 * content of @pages and will pass it verbatim to pcpu_map_pages().
 80 */
 81static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
 82			    struct page **pages, int page_start, int page_end,
 83			    gfp_t gfp)
 84{
 85	unsigned int cpu, tcpu;
 86	int i;
 87
 88	gfp |= __GFP_HIGHMEM;
 89
 90	for_each_possible_cpu(cpu) {
 91		for (i = page_start; i < page_end; i++) {
 92			struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
 93
 94			*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
 95			if (!*pagep)
 96				goto err;
 97		}
 98	}
 99	return 0;
100
101err:
102	while (--i >= page_start)
103		__free_page(pages[pcpu_page_idx(cpu, i)]);
104
105	for_each_possible_cpu(tcpu) {
106		if (tcpu == cpu)
107			break;
108		for (i = page_start; i < page_end; i++)
109			__free_page(pages[pcpu_page_idx(tcpu, i)]);
110	}
111	return -ENOMEM;
112}
113
114/**
115 * pcpu_pre_unmap_flush - flush cache prior to unmapping
116 * @chunk: chunk the regions to be flushed belongs to
117 * @page_start: page index of the first page to be flushed
118 * @page_end: page index of the last page to be flushed + 1
119 *
120 * Pages in [@page_start,@page_end) of @chunk are about to be
121 * unmapped.  Flush cache.  As each flushing trial can be very
122 * expensive, issue flush on the whole region at once rather than
123 * doing it for each cpu.  This could be an overkill but is more
124 * scalable.
125 */
126static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
127				 int page_start, int page_end)
128{
129	flush_cache_vunmap(
130		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
131		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
132}
133
134static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
135{
136	unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
137}
138
139/**
140 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
141 * @chunk: chunk of interest
142 * @pages: pages array which can be used to pass information to free
143 * @page_start: page index of the first page to unmap
144 * @page_end: page index of the last page to unmap + 1
145 *
146 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
147 * Corresponding elements in @pages were cleared by the caller and can
148 * be used to carry information to pcpu_free_pages() which will be
149 * called after all unmaps are finished.  The caller should call
150 * proper pre/post flush functions.
151 */
152static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
153			     struct page **pages, int page_start, int page_end)
154{
155	unsigned int cpu;
156	int i;
157
158	for_each_possible_cpu(cpu) {
159		for (i = page_start; i < page_end; i++) {
160			struct page *page;
161
162			page = pcpu_chunk_page(chunk, cpu, i);
163			WARN_ON(!page);
164			pages[pcpu_page_idx(cpu, i)] = page;
165		}
166		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
167				   page_end - page_start);
168	}
169}
170
171/**
172 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
173 * @chunk: pcpu_chunk the regions to be flushed belong to
174 * @page_start: page index of the first page to be flushed
175 * @page_end: page index of the last page to be flushed + 1
176 *
177 * Pages [@page_start,@page_end) of @chunk have been unmapped.  Flush
178 * TLB for the regions.  This can be skipped if the area is to be
179 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
180 *
181 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
182 * for the whole region.
183 */
184static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
185				      int page_start, int page_end)
186{
187	flush_tlb_kernel_range(
188		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
189		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
190}
191
192static int __pcpu_map_pages(unsigned long addr, struct page **pages,
193			    int nr_pages)
194{
195	return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
196					PAGE_KERNEL, pages);
197}
198
199/**
200 * pcpu_map_pages - map pages into a pcpu_chunk
201 * @chunk: chunk of interest
202 * @pages: pages array containing pages to be mapped
203 * @page_start: page index of the first page to map
204 * @page_end: page index of the last page to map + 1
205 *
206 * For each cpu, map pages [@page_start,@page_end) into @chunk.  The
207 * caller is responsible for calling pcpu_post_map_flush() after all
208 * mappings are complete.
209 *
210 * This function is responsible for setting up whatever is necessary for
211 * reverse lookup (addr -> chunk).
212 */
213static int pcpu_map_pages(struct pcpu_chunk *chunk,
214			  struct page **pages, int page_start, int page_end)
215{
216	unsigned int cpu, tcpu;
217	int i, err;
218
219	for_each_possible_cpu(cpu) {
220		err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
221				       &pages[pcpu_page_idx(cpu, page_start)],
222				       page_end - page_start);
223		if (err < 0)
224			goto err;
225
226		for (i = page_start; i < page_end; i++)
227			pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
228					    chunk);
229	}
230	return 0;
231err:
232	for_each_possible_cpu(tcpu) {
233		if (tcpu == cpu)
234			break;
235		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
236				   page_end - page_start);
237	}
238	pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
239	return err;
240}
241
242/**
243 * pcpu_post_map_flush - flush cache after mapping
244 * @chunk: pcpu_chunk the regions to be flushed belong to
245 * @page_start: page index of the first page to be flushed
246 * @page_end: page index of the last page to be flushed + 1
247 *
248 * Pages [@page_start,@page_end) of @chunk have been mapped.  Flush
249 * cache.
250 *
251 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
252 * for the whole region.
253 */
254static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
255				int page_start, int page_end)
256{
257	flush_cache_vmap(
258		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
259		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
260}
261
262/**
263 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
264 * @chunk: chunk of interest
265 * @page_start: the start page
266 * @page_end: the end page
267 * @gfp: allocation flags passed to the underlying memory allocator
268 *
269 * For each cpu, populate and map pages [@page_start,@page_end) into
270 * @chunk.
271 *
272 * CONTEXT:
273 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
274 */
275static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
276			       int page_start, int page_end, gfp_t gfp)
277{
278	struct page **pages;
279
280	pages = pcpu_get_pages();
281	if (!pages)
282		return -ENOMEM;
283
284	if (pcpu_alloc_pages(chunk, pages, page_start, page_end, gfp))
285		return -ENOMEM;
286
287	if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
288		pcpu_free_pages(chunk, pages, page_start, page_end);
289		return -ENOMEM;
290	}
291	pcpu_post_map_flush(chunk, page_start, page_end);
292
293	return 0;
294}
295
296/**
297 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
298 * @chunk: chunk to depopulate
299 * @page_start: the start page
300 * @page_end: the end page
301 *
302 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
303 * from @chunk.
304 *
305 * CONTEXT:
306 * pcpu_alloc_mutex.
307 */
308static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
309				  int page_start, int page_end)
310{
311	struct page **pages;
312
313	/*
314	 * If control reaches here, there must have been at least one
315	 * successful population attempt so the temp pages array must
316	 * be available now.
317	 */
318	pages = pcpu_get_pages();
319	BUG_ON(!pages);
320
321	/* unmap and free */
322	pcpu_pre_unmap_flush(chunk, page_start, page_end);
323
324	pcpu_unmap_pages(chunk, pages, page_start, page_end);
325
326	/* no need to flush tlb, vmalloc will handle it lazily */
327
328	pcpu_free_pages(chunk, pages, page_start, page_end);
329}
330
331static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp)
 
332{
333	struct pcpu_chunk *chunk;
334	struct vm_struct **vms;
335
336	chunk = pcpu_alloc_chunk(gfp);
337	if (!chunk)
338		return NULL;
339
340	vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
341				pcpu_nr_groups, pcpu_atom_size);
342	if (!vms) {
343		pcpu_free_chunk(chunk);
344		return NULL;
345	}
346
347	chunk->data = vms;
348	chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
349
350	pcpu_stats_chunk_alloc();
351	trace_percpu_create_chunk(chunk->base_addr);
352
353	return chunk;
354}
355
356static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
357{
358	if (!chunk)
359		return;
360
361	pcpu_stats_chunk_dealloc();
362	trace_percpu_destroy_chunk(chunk->base_addr);
363
364	if (chunk->data)
365		pcpu_free_vm_areas(chunk->data, pcpu_nr_groups);
366	pcpu_free_chunk(chunk);
367}
368
369static struct page *pcpu_addr_to_page(void *addr)
370{
371	return vmalloc_to_page(addr);
372}
373
374static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
375{
376	/* no extra restriction */
377	return 0;
378}

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * mm/percpu-vm.c - vmalloc area based chunk allocation
  4 *
  5 * Copyright (C) 2010		SUSE Linux Products GmbH
  6 * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
  7 *
  8 * Chunks are mapped into vmalloc areas and populated page by page.
  9 * This is the default chunk allocator.
 10 */
 11
 12static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
 13				    unsigned int cpu, int page_idx)
 14{
 15	/* must not be used on pre-mapped chunk */
 16	WARN_ON(chunk->immutable);
 17
 18	return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
 19}
 20
 21/**
 22 * pcpu_get_pages - get temp pages array
 23 *
 24 * Returns pointer to array of pointers to struct page which can be indexed
 25 * with pcpu_page_idx().  Note that there is only one array and accesses
 26 * should be serialized by pcpu_alloc_mutex.
 27 *
 28 * RETURNS:
 29 * Pointer to temp pages array on success.
 30 */
 31static struct page **pcpu_get_pages(void)
 32{
 33	static struct page **pages;
 34	size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
 35
 36	lockdep_assert_held(&pcpu_alloc_mutex);
 37
 38	if (!pages)
 39		pages = pcpu_mem_zalloc(pages_size, GFP_KERNEL);
 40	return pages;
 41}
 42
 43/**
 44 * pcpu_free_pages - free pages which were allocated for @chunk
 45 * @chunk: chunk pages were allocated for
 46 * @pages: array of pages to be freed, indexed by pcpu_page_idx()
 47 * @page_start: page index of the first page to be freed
 48 * @page_end: page index of the last page to be freed + 1
 49 *
 50 * Free pages [@page_start and @page_end) in @pages for all units.
 51 * The pages were allocated for @chunk.
 52 */
 53static void pcpu_free_pages(struct pcpu_chunk *chunk,
 54			    struct page **pages, int page_start, int page_end)
 55{
 56	unsigned int cpu;
 57	int i;
 58
 59	for_each_possible_cpu(cpu) {
 60		for (i = page_start; i < page_end; i++) {
 61			struct page *page = pages[pcpu_page_idx(cpu, i)];
 62
 63			if (page)
 64				__free_page(page);
 65		}
 66	}
 67}
 68
 69/**
 70 * pcpu_alloc_pages - allocates pages for @chunk
 71 * @chunk: target chunk
 72 * @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
 73 * @page_start: page index of the first page to be allocated
 74 * @page_end: page index of the last page to be allocated + 1
 75 * @gfp: allocation flags passed to the underlying allocator
 76 *
 77 * Allocate pages [@page_start,@page_end) into @pages for all units.
 78 * The allocation is for @chunk.  Percpu core doesn't care about the
 79 * content of @pages and will pass it verbatim to pcpu_map_pages().
 80 */
 81static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
 82			    struct page **pages, int page_start, int page_end,
 83			    gfp_t gfp)
 84{
 85	unsigned int cpu, tcpu;
 86	int i;
 87
 88	gfp |= __GFP_HIGHMEM;
 89
 90	for_each_possible_cpu(cpu) {
 91		for (i = page_start; i < page_end; i++) {
 92			struct page **pagep = &pages[pcpu_page_idx(cpu, i)];
 93
 94			*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
 95			if (!*pagep)
 96				goto err;
 97		}
 98	}
 99	return 0;
100
101err:
102	while (--i >= page_start)
103		__free_page(pages[pcpu_page_idx(cpu, i)]);
104
105	for_each_possible_cpu(tcpu) {
106		if (tcpu == cpu)
107			break;
108		for (i = page_start; i < page_end; i++)
109			__free_page(pages[pcpu_page_idx(tcpu, i)]);
110	}
111	return -ENOMEM;
112}
113
114/**
115 * pcpu_pre_unmap_flush - flush cache prior to unmapping
116 * @chunk: chunk the regions to be flushed belongs to
117 * @page_start: page index of the first page to be flushed
118 * @page_end: page index of the last page to be flushed + 1
119 *
120 * Pages in [@page_start,@page_end) of @chunk are about to be
121 * unmapped.  Flush cache.  As each flushing trial can be very
122 * expensive, issue flush on the whole region at once rather than
123 * doing it for each cpu.  This could be an overkill but is more
124 * scalable.
125 */
126static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
127				 int page_start, int page_end)
128{
129	flush_cache_vunmap(
130		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
131		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
132}
133
134static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
135{
136	unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
137}
138
139/**
140 * pcpu_unmap_pages - unmap pages out of a pcpu_chunk
141 * @chunk: chunk of interest
142 * @pages: pages array which can be used to pass information to free
143 * @page_start: page index of the first page to unmap
144 * @page_end: page index of the last page to unmap + 1
145 *
146 * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
147 * Corresponding elements in @pages were cleared by the caller and can
148 * be used to carry information to pcpu_free_pages() which will be
149 * called after all unmaps are finished.  The caller should call
150 * proper pre/post flush functions.
151 */
152static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
153			     struct page **pages, int page_start, int page_end)
154{
155	unsigned int cpu;
156	int i;
157
158	for_each_possible_cpu(cpu) {
159		for (i = page_start; i < page_end; i++) {
160			struct page *page;
161
162			page = pcpu_chunk_page(chunk, cpu, i);
163			WARN_ON(!page);
164			pages[pcpu_page_idx(cpu, i)] = page;
165		}
166		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
167				   page_end - page_start);
168	}
169}
170
171/**
172 * pcpu_post_unmap_tlb_flush - flush TLB after unmapping
173 * @chunk: pcpu_chunk the regions to be flushed belong to
174 * @page_start: page index of the first page to be flushed
175 * @page_end: page index of the last page to be flushed + 1
176 *
177 * Pages [@page_start,@page_end) of @chunk have been unmapped.  Flush
178 * TLB for the regions.  This can be skipped if the area is to be
179 * returned to vmalloc as vmalloc will handle TLB flushing lazily.
180 *
181 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
182 * for the whole region.
183 */
184static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
185				      int page_start, int page_end)
186{
187	flush_tlb_kernel_range(
188		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
189		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
190}
191
192static int __pcpu_map_pages(unsigned long addr, struct page **pages,
193			    int nr_pages)
194{
195	return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
196					PAGE_KERNEL, pages);
197}
198
199/**
200 * pcpu_map_pages - map pages into a pcpu_chunk
201 * @chunk: chunk of interest
202 * @pages: pages array containing pages to be mapped
203 * @page_start: page index of the first page to map
204 * @page_end: page index of the last page to map + 1
205 *
206 * For each cpu, map pages [@page_start,@page_end) into @chunk.  The
207 * caller is responsible for calling pcpu_post_map_flush() after all
208 * mappings are complete.
209 *
210 * This function is responsible for setting up whatever is necessary for
211 * reverse lookup (addr -> chunk).
212 */
213static int pcpu_map_pages(struct pcpu_chunk *chunk,
214			  struct page **pages, int page_start, int page_end)
215{
216	unsigned int cpu, tcpu;
217	int i, err;
218
219	for_each_possible_cpu(cpu) {
220		err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
221				       &pages[pcpu_page_idx(cpu, page_start)],
222				       page_end - page_start);
223		if (err < 0)
224			goto err;
225
226		for (i = page_start; i < page_end; i++)
227			pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
228					    chunk);
229	}
230	return 0;
231err:
232	for_each_possible_cpu(tcpu) {
233		if (tcpu == cpu)
234			break;
235		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
236				   page_end - page_start);
237	}
238	pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
239	return err;
240}
241
242/**
243 * pcpu_post_map_flush - flush cache after mapping
244 * @chunk: pcpu_chunk the regions to be flushed belong to
245 * @page_start: page index of the first page to be flushed
246 * @page_end: page index of the last page to be flushed + 1
247 *
248 * Pages [@page_start,@page_end) of @chunk have been mapped.  Flush
249 * cache.
250 *
251 * As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
252 * for the whole region.
253 */
254static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
255				int page_start, int page_end)
256{
257	flush_cache_vmap(
258		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
259		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
260}
261
262/**
263 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
264 * @chunk: chunk of interest
265 * @page_start: the start page
266 * @page_end: the end page
267 * @gfp: allocation flags passed to the underlying memory allocator
268 *
269 * For each cpu, populate and map pages [@page_start,@page_end) into
270 * @chunk.
271 *
272 * CONTEXT:
273 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
274 */
275static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
276			       int page_start, int page_end, gfp_t gfp)
277{
278	struct page **pages;
279
280	pages = pcpu_get_pages();
281	if (!pages)
282		return -ENOMEM;
283
284	if (pcpu_alloc_pages(chunk, pages, page_start, page_end, gfp))
285		return -ENOMEM;
286
287	if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
288		pcpu_free_pages(chunk, pages, page_start, page_end);
289		return -ENOMEM;
290	}
291	pcpu_post_map_flush(chunk, page_start, page_end);
292
293	return 0;
294}
295
296/**
297 * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
298 * @chunk: chunk to depopulate
299 * @page_start: the start page
300 * @page_end: the end page
301 *
302 * For each cpu, depopulate and unmap pages [@page_start,@page_end)
303 * from @chunk.
304 *
305 * CONTEXT:
306 * pcpu_alloc_mutex.
307 */
308static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
309				  int page_start, int page_end)
310{
311	struct page **pages;
312
313	/*
314	 * If control reaches here, there must have been at least one
315	 * successful population attempt so the temp pages array must
316	 * be available now.
317	 */
318	pages = pcpu_get_pages();
319	BUG_ON(!pages);
320
321	/* unmap and free */
322	pcpu_pre_unmap_flush(chunk, page_start, page_end);
323
324	pcpu_unmap_pages(chunk, pages, page_start, page_end);
325
326	/* no need to flush tlb, vmalloc will handle it lazily */
327
328	pcpu_free_pages(chunk, pages, page_start, page_end);
329}
330
331static struct pcpu_chunk *pcpu_create_chunk(enum pcpu_chunk_type type,
332					    gfp_t gfp)
333{
334	struct pcpu_chunk *chunk;
335	struct vm_struct **vms;
336
337	chunk = pcpu_alloc_chunk(type, 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}