Loading...
1/*
2 * Contiguous Memory Allocator for DMA mapping framework
3 * Copyright (c) 2010-2011 by Samsung Electronics.
4 * Written by:
5 * Marek Szyprowski <m.szyprowski@samsung.com>
6 * Michal Nazarewicz <mina86@mina86.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License or (at your optional) any later version of the license.
12 */
13
14#define pr_fmt(fmt) "cma: " fmt
15
16#ifdef CONFIG_CMA_DEBUG
17#ifndef DEBUG
18# define DEBUG
19#endif
20#endif
21
22#include <asm/page.h>
23#include <asm/dma-contiguous.h>
24
25#include <linux/memblock.h>
26#include <linux/err.h>
27#include <linux/mm.h>
28#include <linux/mutex.h>
29#include <linux/page-isolation.h>
30#include <linux/sizes.h>
31#include <linux/slab.h>
32#include <linux/swap.h>
33#include <linux/mm_types.h>
34#include <linux/dma-contiguous.h>
35
36struct cma {
37 unsigned long base_pfn;
38 unsigned long count;
39 unsigned long *bitmap;
40};
41
42struct cma *dma_contiguous_default_area;
43
44#ifdef CONFIG_CMA_SIZE_MBYTES
45#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
46#else
47#define CMA_SIZE_MBYTES 0
48#endif
49
50/*
51 * Default global CMA area size can be defined in kernel's .config.
52 * This is useful mainly for distro maintainers to create a kernel
53 * that works correctly for most supported systems.
54 * The size can be set in bytes or as a percentage of the total memory
55 * in the system.
56 *
57 * Users, who want to set the size of global CMA area for their system
58 * should use cma= kernel parameter.
59 */
60static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
61static phys_addr_t size_cmdline = -1;
62
63static int __init early_cma(char *p)
64{
65 pr_debug("%s(%s)\n", __func__, p);
66 size_cmdline = memparse(p, &p);
67 return 0;
68}
69early_param("cma", early_cma);
70
71#ifdef CONFIG_CMA_SIZE_PERCENTAGE
72
73static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
74{
75 struct memblock_region *reg;
76 unsigned long total_pages = 0;
77
78 /*
79 * We cannot use memblock_phys_mem_size() here, because
80 * memblock_analyze() has not been called yet.
81 */
82 for_each_memblock(memory, reg)
83 total_pages += memblock_region_memory_end_pfn(reg) -
84 memblock_region_memory_base_pfn(reg);
85
86 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
87}
88
89#else
90
91static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
92{
93 return 0;
94}
95
96#endif
97
98/**
99 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
100 * @limit: End address of the reserved memory (optional, 0 for any).
101 *
102 * This function reserves memory from early allocator. It should be
103 * called by arch specific code once the early allocator (memblock or bootmem)
104 * has been activated and all other subsystems have already allocated/reserved
105 * memory.
106 */
107void __init dma_contiguous_reserve(phys_addr_t limit)
108{
109 phys_addr_t selected_size = 0;
110
111 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
112
113 if (size_cmdline != -1) {
114 selected_size = size_cmdline;
115 } else {
116#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
117 selected_size = size_bytes;
118#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
119 selected_size = cma_early_percent_memory();
120#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
121 selected_size = min(size_bytes, cma_early_percent_memory());
122#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
123 selected_size = max(size_bytes, cma_early_percent_memory());
124#endif
125 }
126
127 if (selected_size && !dma_contiguous_default_area) {
128 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
129 (unsigned long)selected_size / SZ_1M);
130
131 dma_contiguous_reserve_area(selected_size, 0, limit,
132 &dma_contiguous_default_area);
133 }
134};
135
136static DEFINE_MUTEX(cma_mutex);
137
138static int __init cma_activate_area(struct cma *cma)
139{
140 int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
141 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
142 unsigned i = cma->count >> pageblock_order;
143 struct zone *zone;
144
145 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
146
147 if (!cma->bitmap)
148 return -ENOMEM;
149
150 WARN_ON_ONCE(!pfn_valid(pfn));
151 zone = page_zone(pfn_to_page(pfn));
152
153 do {
154 unsigned j;
155 base_pfn = pfn;
156 for (j = pageblock_nr_pages; j; --j, pfn++) {
157 WARN_ON_ONCE(!pfn_valid(pfn));
158 if (page_zone(pfn_to_page(pfn)) != zone)
159 return -EINVAL;
160 }
161 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
162 } while (--i);
163
164 return 0;
165}
166
167static struct cma cma_areas[MAX_CMA_AREAS];
168static unsigned cma_area_count;
169
170static int __init cma_init_reserved_areas(void)
171{
172 int i;
173
174 for (i = 0; i < cma_area_count; i++) {
175 int ret = cma_activate_area(&cma_areas[i]);
176 if (ret)
177 return ret;
178 }
179
180 return 0;
181}
182core_initcall(cma_init_reserved_areas);
183
184/**
185 * dma_contiguous_reserve_area() - reserve custom contiguous area
186 * @size: Size of the reserved area (in bytes),
187 * @base: Base address of the reserved area optional, use 0 for any
188 * @limit: End address of the reserved memory (optional, 0 for any).
189 * @res_cma: Pointer to store the created cma region.
190 *
191 * This function reserves memory from early allocator. It should be
192 * called by arch specific code once the early allocator (memblock or bootmem)
193 * has been activated and all other subsystems have already allocated/reserved
194 * memory. This function allows to create custom reserved areas for specific
195 * devices.
196 */
197int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
198 phys_addr_t limit, struct cma **res_cma)
199{
200 struct cma *cma = &cma_areas[cma_area_count];
201 phys_addr_t alignment;
202 int ret = 0;
203
204 pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
205 (unsigned long)size, (unsigned long)base,
206 (unsigned long)limit);
207
208 /* Sanity checks */
209 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
210 pr_err("Not enough slots for CMA reserved regions!\n");
211 return -ENOSPC;
212 }
213
214 if (!size)
215 return -EINVAL;
216
217 /* Sanitise input arguments */
218 alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
219 base = ALIGN(base, alignment);
220 size = ALIGN(size, alignment);
221 limit &= ~(alignment - 1);
222
223 /* Reserve memory */
224 if (base) {
225 if (memblock_is_region_reserved(base, size) ||
226 memblock_reserve(base, size) < 0) {
227 ret = -EBUSY;
228 goto err;
229 }
230 } else {
231 /*
232 * Use __memblock_alloc_base() since
233 * memblock_alloc_base() panic()s.
234 */
235 phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
236 if (!addr) {
237 ret = -ENOMEM;
238 goto err;
239 } else {
240 base = addr;
241 }
242 }
243
244 /*
245 * Each reserved area must be initialised later, when more kernel
246 * subsystems (like slab allocator) are available.
247 */
248 cma->base_pfn = PFN_DOWN(base);
249 cma->count = size >> PAGE_SHIFT;
250 *res_cma = cma;
251 cma_area_count++;
252
253 pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
254 (unsigned long)base);
255
256 /* Architecture specific contiguous memory fixup. */
257 dma_contiguous_early_fixup(base, size);
258 return 0;
259err:
260 pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
261 return ret;
262}
263
264/**
265 * dma_alloc_from_contiguous() - allocate pages from contiguous area
266 * @dev: Pointer to device for which the allocation is performed.
267 * @count: Requested number of pages.
268 * @align: Requested alignment of pages (in PAGE_SIZE order).
269 *
270 * This function allocates memory buffer for specified device. It uses
271 * device specific contiguous memory area if available or the default
272 * global one. Requires architecture specific get_dev_cma_area() helper
273 * function.
274 */
275struct page *dma_alloc_from_contiguous(struct device *dev, int count,
276 unsigned int align)
277{
278 unsigned long mask, pfn, pageno, start = 0;
279 struct cma *cma = dev_get_cma_area(dev);
280 struct page *page = NULL;
281 int ret;
282
283 if (!cma || !cma->count)
284 return NULL;
285
286 if (align > CONFIG_CMA_ALIGNMENT)
287 align = CONFIG_CMA_ALIGNMENT;
288
289 pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
290 count, align);
291
292 if (!count)
293 return NULL;
294
295 mask = (1 << align) - 1;
296
297 mutex_lock(&cma_mutex);
298
299 for (;;) {
300 pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
301 start, count, mask);
302 if (pageno >= cma->count)
303 break;
304
305 pfn = cma->base_pfn + pageno;
306 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
307 if (ret == 0) {
308 bitmap_set(cma->bitmap, pageno, count);
309 page = pfn_to_page(pfn);
310 break;
311 } else if (ret != -EBUSY) {
312 break;
313 }
314 pr_debug("%s(): memory range at %p is busy, retrying\n",
315 __func__, pfn_to_page(pfn));
316 /* try again with a bit different memory target */
317 start = pageno + mask + 1;
318 }
319
320 mutex_unlock(&cma_mutex);
321 pr_debug("%s(): returned %p\n", __func__, page);
322 return page;
323}
324
325/**
326 * dma_release_from_contiguous() - release allocated pages
327 * @dev: Pointer to device for which the pages were allocated.
328 * @pages: Allocated pages.
329 * @count: Number of allocated pages.
330 *
331 * This function releases memory allocated by dma_alloc_from_contiguous().
332 * It returns false when provided pages do not belong to contiguous area and
333 * true otherwise.
334 */
335bool dma_release_from_contiguous(struct device *dev, struct page *pages,
336 int count)
337{
338 struct cma *cma = dev_get_cma_area(dev);
339 unsigned long pfn;
340
341 if (!cma || !pages)
342 return false;
343
344 pr_debug("%s(page %p)\n", __func__, (void *)pages);
345
346 pfn = page_to_pfn(pages);
347
348 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
349 return false;
350
351 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
352
353 mutex_lock(&cma_mutex);
354 bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
355 free_contig_range(pfn, count);
356 mutex_unlock(&cma_mutex);
357
358 return true;
359}
1/*
2 * Contiguous Memory Allocator for DMA mapping framework
3 * Copyright (c) 2010-2011 by Samsung Electronics.
4 * Written by:
5 * Marek Szyprowski <m.szyprowski@samsung.com>
6 * Michal Nazarewicz <mina86@mina86.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License or (at your optional) any later version of the license.
12 */
13
14#define pr_fmt(fmt) "cma: " fmt
15
16#ifdef CONFIG_CMA_DEBUG
17#ifndef DEBUG
18# define DEBUG
19#endif
20#endif
21
22#include <asm/page.h>
23#include <asm/dma-contiguous.h>
24
25#include <linux/memblock.h>
26#include <linux/err.h>
27#include <linux/mm.h>
28#include <linux/mutex.h>
29#include <linux/page-isolation.h>
30#include <linux/slab.h>
31#include <linux/swap.h>
32#include <linux/mm_types.h>
33#include <linux/dma-contiguous.h>
34
35#ifndef SZ_1M
36#define SZ_1M (1 << 20)
37#endif
38
39struct cma {
40 unsigned long base_pfn;
41 unsigned long count;
42 unsigned long *bitmap;
43};
44
45struct cma *dma_contiguous_default_area;
46
47#ifdef CONFIG_CMA_SIZE_MBYTES
48#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
49#else
50#define CMA_SIZE_MBYTES 0
51#endif
52
53/*
54 * Default global CMA area size can be defined in kernel's .config.
55 * This is usefull mainly for distro maintainers to create a kernel
56 * that works correctly for most supported systems.
57 * The size can be set in bytes or as a percentage of the total memory
58 * in the system.
59 *
60 * Users, who want to set the size of global CMA area for their system
61 * should use cma= kernel parameter.
62 */
63static const unsigned long size_bytes = CMA_SIZE_MBYTES * SZ_1M;
64static long size_cmdline = -1;
65
66static int __init early_cma(char *p)
67{
68 pr_debug("%s(%s)\n", __func__, p);
69 size_cmdline = memparse(p, &p);
70 return 0;
71}
72early_param("cma", early_cma);
73
74#ifdef CONFIG_CMA_SIZE_PERCENTAGE
75
76static unsigned long __init __maybe_unused cma_early_percent_memory(void)
77{
78 struct memblock_region *reg;
79 unsigned long total_pages = 0;
80
81 /*
82 * We cannot use memblock_phys_mem_size() here, because
83 * memblock_analyze() has not been called yet.
84 */
85 for_each_memblock(memory, reg)
86 total_pages += memblock_region_memory_end_pfn(reg) -
87 memblock_region_memory_base_pfn(reg);
88
89 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
90}
91
92#else
93
94static inline __maybe_unused unsigned long cma_early_percent_memory(void)
95{
96 return 0;
97}
98
99#endif
100
101/**
102 * dma_contiguous_reserve() - reserve area for contiguous memory handling
103 * @limit: End address of the reserved memory (optional, 0 for any).
104 *
105 * This function reserves memory from early allocator. It should be
106 * called by arch specific code once the early allocator (memblock or bootmem)
107 * has been activated and all other subsystems have already allocated/reserved
108 * memory.
109 */
110void __init dma_contiguous_reserve(phys_addr_t limit)
111{
112 unsigned long selected_size = 0;
113
114 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
115
116 if (size_cmdline != -1) {
117 selected_size = size_cmdline;
118 } else {
119#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
120 selected_size = size_bytes;
121#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
122 selected_size = cma_early_percent_memory();
123#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
124 selected_size = min(size_bytes, cma_early_percent_memory());
125#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
126 selected_size = max(size_bytes, cma_early_percent_memory());
127#endif
128 }
129
130 if (selected_size) {
131 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
132 selected_size / SZ_1M);
133
134 dma_declare_contiguous(NULL, selected_size, 0, limit);
135 }
136};
137
138static DEFINE_MUTEX(cma_mutex);
139
140static __init int cma_activate_area(unsigned long base_pfn, unsigned long count)
141{
142 unsigned long pfn = base_pfn;
143 unsigned i = count >> pageblock_order;
144 struct zone *zone;
145
146 WARN_ON_ONCE(!pfn_valid(pfn));
147 zone = page_zone(pfn_to_page(pfn));
148
149 do {
150 unsigned j;
151 base_pfn = pfn;
152 for (j = pageblock_nr_pages; j; --j, pfn++) {
153 WARN_ON_ONCE(!pfn_valid(pfn));
154 if (page_zone(pfn_to_page(pfn)) != zone)
155 return -EINVAL;
156 }
157 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
158 } while (--i);
159 return 0;
160}
161
162static __init struct cma *cma_create_area(unsigned long base_pfn,
163 unsigned long count)
164{
165 int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
166 struct cma *cma;
167 int ret = -ENOMEM;
168
169 pr_debug("%s(base %08lx, count %lx)\n", __func__, base_pfn, count);
170
171 cma = kmalloc(sizeof *cma, GFP_KERNEL);
172 if (!cma)
173 return ERR_PTR(-ENOMEM);
174
175 cma->base_pfn = base_pfn;
176 cma->count = count;
177 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
178
179 if (!cma->bitmap)
180 goto no_mem;
181
182 ret = cma_activate_area(base_pfn, count);
183 if (ret)
184 goto error;
185
186 pr_debug("%s: returned %p\n", __func__, (void *)cma);
187 return cma;
188
189error:
190 kfree(cma->bitmap);
191no_mem:
192 kfree(cma);
193 return ERR_PTR(ret);
194}
195
196static struct cma_reserved {
197 phys_addr_t start;
198 unsigned long size;
199 struct device *dev;
200} cma_reserved[MAX_CMA_AREAS] __initdata;
201static unsigned cma_reserved_count __initdata;
202
203static int __init cma_init_reserved_areas(void)
204{
205 struct cma_reserved *r = cma_reserved;
206 unsigned i = cma_reserved_count;
207
208 pr_debug("%s()\n", __func__);
209
210 for (; i; --i, ++r) {
211 struct cma *cma;
212 cma = cma_create_area(PFN_DOWN(r->start),
213 r->size >> PAGE_SHIFT);
214 if (!IS_ERR(cma))
215 dev_set_cma_area(r->dev, cma);
216 }
217 return 0;
218}
219core_initcall(cma_init_reserved_areas);
220
221/**
222 * dma_declare_contiguous() - reserve area for contiguous memory handling
223 * for particular device
224 * @dev: Pointer to device structure.
225 * @size: Size of the reserved memory.
226 * @base: Start address of the reserved memory (optional, 0 for any).
227 * @limit: End address of the reserved memory (optional, 0 for any).
228 *
229 * This function reserves memory for specified device. It should be
230 * called by board specific code when early allocator (memblock or bootmem)
231 * is still activate.
232 */
233int __init dma_declare_contiguous(struct device *dev, unsigned long size,
234 phys_addr_t base, phys_addr_t limit)
235{
236 struct cma_reserved *r = &cma_reserved[cma_reserved_count];
237 unsigned long alignment;
238
239 pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
240 (unsigned long)size, (unsigned long)base,
241 (unsigned long)limit);
242
243 /* Sanity checks */
244 if (cma_reserved_count == ARRAY_SIZE(cma_reserved)) {
245 pr_err("Not enough slots for CMA reserved regions!\n");
246 return -ENOSPC;
247 }
248
249 if (!size)
250 return -EINVAL;
251
252 /* Sanitise input arguments */
253 alignment = PAGE_SIZE << max(MAX_ORDER, pageblock_order);
254 base = ALIGN(base, alignment);
255 size = ALIGN(size, alignment);
256 limit &= ~(alignment - 1);
257
258 /* Reserve memory */
259 if (base) {
260 if (memblock_is_region_reserved(base, size) ||
261 memblock_reserve(base, size) < 0) {
262 base = -EBUSY;
263 goto err;
264 }
265 } else {
266 /*
267 * Use __memblock_alloc_base() since
268 * memblock_alloc_base() panic()s.
269 */
270 phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
271 if (!addr) {
272 base = -ENOMEM;
273 goto err;
274 } else if (addr + size > ~(unsigned long)0) {
275 memblock_free(addr, size);
276 base = -EINVAL;
277 goto err;
278 } else {
279 base = addr;
280 }
281 }
282
283 /*
284 * Each reserved area must be initialised later, when more kernel
285 * subsystems (like slab allocator) are available.
286 */
287 r->start = base;
288 r->size = size;
289 r->dev = dev;
290 cma_reserved_count++;
291 pr_info("CMA: reserved %ld MiB at %08lx\n", size / SZ_1M,
292 (unsigned long)base);
293
294 /* Architecture specific contiguous memory fixup. */
295 dma_contiguous_early_fixup(base, size);
296 return 0;
297err:
298 pr_err("CMA: failed to reserve %ld MiB\n", size / SZ_1M);
299 return base;
300}
301
302/**
303 * dma_alloc_from_contiguous() - allocate pages from contiguous area
304 * @dev: Pointer to device for which the allocation is performed.
305 * @count: Requested number of pages.
306 * @align: Requested alignment of pages (in PAGE_SIZE order).
307 *
308 * This function allocates memory buffer for specified device. It uses
309 * device specific contiguous memory area if available or the default
310 * global one. Requires architecture specific get_dev_cma_area() helper
311 * function.
312 */
313struct page *dma_alloc_from_contiguous(struct device *dev, int count,
314 unsigned int align)
315{
316 unsigned long mask, pfn, pageno, start = 0;
317 struct cma *cma = dev_get_cma_area(dev);
318 int ret;
319
320 if (!cma || !cma->count)
321 return NULL;
322
323 if (align > CONFIG_CMA_ALIGNMENT)
324 align = CONFIG_CMA_ALIGNMENT;
325
326 pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
327 count, align);
328
329 if (!count)
330 return NULL;
331
332 mask = (1 << align) - 1;
333
334 mutex_lock(&cma_mutex);
335
336 for (;;) {
337 pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
338 start, count, mask);
339 if (pageno >= cma->count) {
340 ret = -ENOMEM;
341 goto error;
342 }
343
344 pfn = cma->base_pfn + pageno;
345 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
346 if (ret == 0) {
347 bitmap_set(cma->bitmap, pageno, count);
348 break;
349 } else if (ret != -EBUSY) {
350 goto error;
351 }
352 pr_debug("%s(): memory range at %p is busy, retrying\n",
353 __func__, pfn_to_page(pfn));
354 /* try again with a bit different memory target */
355 start = pageno + mask + 1;
356 }
357
358 mutex_unlock(&cma_mutex);
359
360 pr_debug("%s(): returned %p\n", __func__, pfn_to_page(pfn));
361 return pfn_to_page(pfn);
362error:
363 mutex_unlock(&cma_mutex);
364 return NULL;
365}
366
367/**
368 * dma_release_from_contiguous() - release allocated pages
369 * @dev: Pointer to device for which the pages were allocated.
370 * @pages: Allocated pages.
371 * @count: Number of allocated pages.
372 *
373 * This function releases memory allocated by dma_alloc_from_contiguous().
374 * It returns false when provided pages do not belong to contiguous area and
375 * true otherwise.
376 */
377bool dma_release_from_contiguous(struct device *dev, struct page *pages,
378 int count)
379{
380 struct cma *cma = dev_get_cma_area(dev);
381 unsigned long pfn;
382
383 if (!cma || !pages)
384 return false;
385
386 pr_debug("%s(page %p)\n", __func__, (void *)pages);
387
388 pfn = page_to_pfn(pages);
389
390 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
391 return false;
392
393 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
394
395 mutex_lock(&cma_mutex);
396 bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
397 free_contig_range(pfn, count);
398 mutex_unlock(&cma_mutex);
399
400 return true;
401}