1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Digital Audio (PCM) abstract layer |
4 | * Copyright (c) by Jaroslav Kysela <perex@perex.cz> |
5 | */ |
6 | |
7 | #include <linux/io.h> |
8 | #include <linux/time.h> |
9 | #include <linux/init.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/moduleparam.h> |
12 | #include <linux/vmalloc.h> |
13 | #include <linux/export.h> |
14 | #include <sound/core.h> |
15 | #include <sound/pcm.h> |
16 | #include <sound/info.h> |
17 | #include <sound/initval.h> |
18 | #include "pcm_local.h" |
19 | |
20 | static int preallocate_dma = 1; |
21 | module_param(preallocate_dma, int, 0444); |
22 | MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized." ); |
23 | |
24 | static int maximum_substreams = 4; |
25 | module_param(maximum_substreams, int, 0444); |
26 | MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory." ); |
27 | |
28 | static const size_t snd_minimum_buffer = 16384; |
29 | |
30 | static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL; |
31 | module_param(max_alloc_per_card, ulong, 0644); |
32 | MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card." ); |
33 | |
34 | static void __update_allocated_size(struct snd_card *card, ssize_t bytes) |
35 | { |
36 | card->total_pcm_alloc_bytes += bytes; |
37 | } |
38 | |
39 | static void update_allocated_size(struct snd_card *card, ssize_t bytes) |
40 | { |
41 | mutex_lock(&card->memory_mutex); |
42 | __update_allocated_size(card, bytes); |
43 | mutex_unlock(lock: &card->memory_mutex); |
44 | } |
45 | |
46 | static void decrease_allocated_size(struct snd_card *card, size_t bytes) |
47 | { |
48 | mutex_lock(&card->memory_mutex); |
49 | WARN_ON(card->total_pcm_alloc_bytes < bytes); |
50 | __update_allocated_size(card, bytes: -(ssize_t)bytes); |
51 | mutex_unlock(lock: &card->memory_mutex); |
52 | } |
53 | |
54 | static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, |
55 | int str, size_t size, struct snd_dma_buffer *dmab) |
56 | { |
57 | enum dma_data_direction dir; |
58 | int err; |
59 | |
60 | /* check and reserve the requested size */ |
61 | mutex_lock(&card->memory_mutex); |
62 | if (max_alloc_per_card && |
63 | card->total_pcm_alloc_bytes + size > max_alloc_per_card) { |
64 | mutex_unlock(lock: &card->memory_mutex); |
65 | return -ENOMEM; |
66 | } |
67 | __update_allocated_size(card, bytes: size); |
68 | mutex_unlock(lock: &card->memory_mutex); |
69 | |
70 | if (str == SNDRV_PCM_STREAM_PLAYBACK) |
71 | dir = DMA_TO_DEVICE; |
72 | else |
73 | dir = DMA_FROM_DEVICE; |
74 | err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab); |
75 | if (!err) { |
76 | /* the actual allocation size might be bigger than requested, |
77 | * and we need to correct the account |
78 | */ |
79 | if (dmab->bytes != size) |
80 | update_allocated_size(card, bytes: dmab->bytes - size); |
81 | } else { |
82 | /* take back on allocation failure */ |
83 | decrease_allocated_size(card, bytes: size); |
84 | } |
85 | return err; |
86 | } |
87 | |
88 | static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab) |
89 | { |
90 | if (!dmab->area) |
91 | return; |
92 | decrease_allocated_size(card, bytes: dmab->bytes); |
93 | snd_dma_free_pages(dmab); |
94 | dmab->area = NULL; |
95 | } |
96 | |
97 | /* |
98 | * try to allocate as the large pages as possible. |
99 | * stores the resultant memory size in *res_size. |
100 | * |
101 | * the minimum size is snd_minimum_buffer. it should be power of 2. |
102 | */ |
103 | static int preallocate_pcm_pages(struct snd_pcm_substream *substream, |
104 | size_t size, bool no_fallback) |
105 | { |
106 | struct snd_dma_buffer *dmab = &substream->dma_buffer; |
107 | struct snd_card *card = substream->pcm->card; |
108 | size_t orig_size = size; |
109 | int err; |
110 | |
111 | do { |
112 | err = do_alloc_pages(card, type: dmab->dev.type, dev: dmab->dev.dev, |
113 | str: substream->stream, size, dmab); |
114 | if (err != -ENOMEM) |
115 | return err; |
116 | if (no_fallback) |
117 | break; |
118 | size >>= 1; |
119 | } while (size >= snd_minimum_buffer); |
120 | dmab->bytes = 0; /* tell error */ |
121 | pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n" , |
122 | substream->pcm->card->number, substream->pcm->device, |
123 | substream->stream ? 'c' : 'p', substream->number, |
124 | substream->pcm->name, orig_size); |
125 | return -ENOMEM; |
126 | } |
127 | |
128 | /** |
129 | * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream. |
130 | * @substream: the pcm substream instance |
131 | * |
132 | * Releases the pre-allocated buffer of the given substream. |
133 | */ |
134 | void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream) |
135 | { |
136 | do_free_pages(card: substream->pcm->card, dmab: &substream->dma_buffer); |
137 | } |
138 | |
139 | /** |
140 | * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm |
141 | * @pcm: the pcm instance |
142 | * |
143 | * Releases all the pre-allocated buffers on the given pcm. |
144 | */ |
145 | void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm) |
146 | { |
147 | struct snd_pcm_substream *substream; |
148 | int stream; |
149 | |
150 | for_each_pcm_substream(pcm, stream, substream) |
151 | snd_pcm_lib_preallocate_free(substream); |
152 | } |
153 | EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all); |
154 | |
155 | #ifdef CONFIG_SND_VERBOSE_PROCFS |
156 | /* |
157 | * read callback for prealloc proc file |
158 | * |
159 | * prints the current allocated size in kB. |
160 | */ |
161 | static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry, |
162 | struct snd_info_buffer *buffer) |
163 | { |
164 | struct snd_pcm_substream *substream = entry->private_data; |
165 | snd_iprintf(buffer, "%lu\n" , (unsigned long) substream->dma_buffer.bytes / 1024); |
166 | } |
167 | |
168 | /* |
169 | * read callback for prealloc_max proc file |
170 | * |
171 | * prints the maximum allowed size in kB. |
172 | */ |
173 | static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry, |
174 | struct snd_info_buffer *buffer) |
175 | { |
176 | struct snd_pcm_substream *substream = entry->private_data; |
177 | snd_iprintf(buffer, "%lu\n" , (unsigned long) substream->dma_max / 1024); |
178 | } |
179 | |
180 | /* |
181 | * write callback for prealloc proc file |
182 | * |
183 | * accepts the preallocation size in kB. |
184 | */ |
185 | static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry, |
186 | struct snd_info_buffer *buffer) |
187 | { |
188 | struct snd_pcm_substream *substream = entry->private_data; |
189 | struct snd_card *card = substream->pcm->card; |
190 | char line[64], str[64]; |
191 | size_t size; |
192 | struct snd_dma_buffer new_dmab; |
193 | |
194 | mutex_lock(&substream->pcm->open_mutex); |
195 | if (substream->runtime) { |
196 | buffer->error = -EBUSY; |
197 | goto unlock; |
198 | } |
199 | if (!snd_info_get_line(buffer, line, len: sizeof(line))) { |
200 | snd_info_get_str(dest: str, src: line, len: sizeof(str)); |
201 | size = simple_strtoul(str, NULL, 10) * 1024; |
202 | if ((size != 0 && size < 8192) || size > substream->dma_max) { |
203 | buffer->error = -EINVAL; |
204 | goto unlock; |
205 | } |
206 | if (substream->dma_buffer.bytes == size) |
207 | goto unlock; |
208 | memset(&new_dmab, 0, sizeof(new_dmab)); |
209 | new_dmab.dev = substream->dma_buffer.dev; |
210 | if (size > 0) { |
211 | if (do_alloc_pages(card, |
212 | type: substream->dma_buffer.dev.type, |
213 | dev: substream->dma_buffer.dev.dev, |
214 | str: substream->stream, |
215 | size, dmab: &new_dmab) < 0) { |
216 | buffer->error = -ENOMEM; |
217 | pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n" , |
218 | substream->pcm->card->number, substream->pcm->device, |
219 | substream->stream ? 'c' : 'p', substream->number, |
220 | substream->pcm->name, size); |
221 | goto unlock; |
222 | } |
223 | substream->buffer_bytes_max = size; |
224 | } else { |
225 | substream->buffer_bytes_max = UINT_MAX; |
226 | } |
227 | if (substream->dma_buffer.area) |
228 | do_free_pages(card, dmab: &substream->dma_buffer); |
229 | substream->dma_buffer = new_dmab; |
230 | } else { |
231 | buffer->error = -EINVAL; |
232 | } |
233 | unlock: |
234 | mutex_unlock(lock: &substream->pcm->open_mutex); |
235 | } |
236 | |
237 | static inline void preallocate_info_init(struct snd_pcm_substream *substream) |
238 | { |
239 | struct snd_info_entry *entry; |
240 | |
241 | entry = snd_info_create_card_entry(card: substream->pcm->card, name: "prealloc" , |
242 | parent: substream->proc_root); |
243 | if (entry) { |
244 | snd_info_set_text_ops(entry, private_data: substream, |
245 | read: snd_pcm_lib_preallocate_proc_read); |
246 | entry->c.text.write = snd_pcm_lib_preallocate_proc_write; |
247 | entry->mode |= 0200; |
248 | } |
249 | entry = snd_info_create_card_entry(card: substream->pcm->card, name: "prealloc_max" , |
250 | parent: substream->proc_root); |
251 | if (entry) |
252 | snd_info_set_text_ops(entry, private_data: substream, |
253 | read: snd_pcm_lib_preallocate_max_proc_read); |
254 | } |
255 | |
256 | #else /* !CONFIG_SND_VERBOSE_PROCFS */ |
257 | static inline void preallocate_info_init(struct snd_pcm_substream *substream) |
258 | { |
259 | } |
260 | #endif /* CONFIG_SND_VERBOSE_PROCFS */ |
261 | |
262 | /* |
263 | * pre-allocate the buffer and create a proc file for the substream |
264 | */ |
265 | static int preallocate_pages(struct snd_pcm_substream *substream, |
266 | int type, struct device *data, |
267 | size_t size, size_t max, bool managed) |
268 | { |
269 | int err; |
270 | |
271 | if (snd_BUG_ON(substream->dma_buffer.dev.type)) |
272 | return -EINVAL; |
273 | |
274 | substream->dma_buffer.dev.type = type; |
275 | substream->dma_buffer.dev.dev = data; |
276 | |
277 | if (size > 0) { |
278 | if (!max) { |
279 | /* no fallback, only also inform -ENOMEM */ |
280 | err = preallocate_pcm_pages(substream, size, no_fallback: true); |
281 | if (err < 0) |
282 | return err; |
283 | } else if (preallocate_dma && |
284 | substream->number < maximum_substreams) { |
285 | err = preallocate_pcm_pages(substream, size, no_fallback: false); |
286 | if (err < 0 && err != -ENOMEM) |
287 | return err; |
288 | } |
289 | } |
290 | |
291 | if (substream->dma_buffer.bytes > 0) |
292 | substream->buffer_bytes_max = substream->dma_buffer.bytes; |
293 | substream->dma_max = max; |
294 | if (max > 0) |
295 | preallocate_info_init(substream); |
296 | if (managed) |
297 | substream->managed_buffer_alloc = 1; |
298 | return 0; |
299 | } |
300 | |
301 | static int preallocate_pages_for_all(struct snd_pcm *pcm, int type, |
302 | void *data, size_t size, size_t max, |
303 | bool managed) |
304 | { |
305 | struct snd_pcm_substream *substream; |
306 | int stream, err; |
307 | |
308 | for_each_pcm_substream(pcm, stream, substream) { |
309 | err = preallocate_pages(substream, type, data, size, max, managed); |
310 | if (err < 0) |
311 | return err; |
312 | } |
313 | return 0; |
314 | } |
315 | |
316 | /** |
317 | * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type |
318 | * @substream: the pcm substream instance |
319 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
320 | * @data: DMA type dependent data |
321 | * @size: the requested pre-allocation size in bytes |
322 | * @max: the max. allowed pre-allocation size |
323 | * |
324 | * Do pre-allocation for the given DMA buffer type. |
325 | */ |
326 | void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream, |
327 | int type, struct device *data, |
328 | size_t size, size_t max) |
329 | { |
330 | preallocate_pages(substream, type, data, size, max, managed: false); |
331 | } |
332 | EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages); |
333 | |
334 | /** |
335 | * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams) |
336 | * @pcm: the pcm instance |
337 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
338 | * @data: DMA type dependent data |
339 | * @size: the requested pre-allocation size in bytes |
340 | * @max: the max. allowed pre-allocation size |
341 | * |
342 | * Do pre-allocation to all substreams of the given pcm for the |
343 | * specified DMA type. |
344 | */ |
345 | void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm, |
346 | int type, void *data, |
347 | size_t size, size_t max) |
348 | { |
349 | preallocate_pages_for_all(pcm, type, data, size, max, managed: false); |
350 | } |
351 | EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all); |
352 | |
353 | /** |
354 | * snd_pcm_set_managed_buffer - set up buffer management for a substream |
355 | * @substream: the pcm substream instance |
356 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
357 | * @data: DMA type dependent data |
358 | * @size: the requested pre-allocation size in bytes |
359 | * @max: the max. allowed pre-allocation size |
360 | * |
361 | * Do pre-allocation for the given DMA buffer type, and set the managed |
362 | * buffer allocation mode to the given substream. |
363 | * In this mode, PCM core will allocate a buffer automatically before PCM |
364 | * hw_params ops call, and release the buffer after PCM hw_free ops call |
365 | * as well, so that the driver doesn't need to invoke the allocation and |
366 | * the release explicitly in its callback. |
367 | * When a buffer is actually allocated before the PCM hw_params call, it |
368 | * turns on the runtime buffer_changed flag for drivers changing their h/w |
369 | * parameters accordingly. |
370 | * |
371 | * When @size is non-zero and @max is zero, this tries to allocate for only |
372 | * the exact buffer size without fallback, and may return -ENOMEM. |
373 | * Otherwise, the function tries to allocate smaller chunks if the allocation |
374 | * fails. This is the behavior of snd_pcm_set_fixed_buffer(). |
375 | * |
376 | * When both @size and @max are zero, the function only sets up the buffer |
377 | * for later dynamic allocations. It's used typically for buffers with |
378 | * SNDRV_DMA_TYPE_VMALLOC type. |
379 | * |
380 | * Upon successful buffer allocation and setup, the function returns 0. |
381 | * |
382 | * Return: zero if successful, or a negative error code |
383 | */ |
384 | int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type, |
385 | struct device *data, size_t size, size_t max) |
386 | { |
387 | return preallocate_pages(substream, type, data, size, max, managed: true); |
388 | } |
389 | EXPORT_SYMBOL(snd_pcm_set_managed_buffer); |
390 | |
391 | /** |
392 | * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams |
393 | * for all substreams |
394 | * @pcm: the pcm instance |
395 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
396 | * @data: DMA type dependent data |
397 | * @size: the requested pre-allocation size in bytes |
398 | * @max: the max. allowed pre-allocation size |
399 | * |
400 | * Do pre-allocation to all substreams of the given pcm for the specified DMA |
401 | * type and size, and set the managed_buffer_alloc flag to each substream. |
402 | * |
403 | * Return: zero if successful, or a negative error code |
404 | */ |
405 | int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type, |
406 | struct device *data, |
407 | size_t size, size_t max) |
408 | { |
409 | return preallocate_pages_for_all(pcm, type, data, size, max, managed: true); |
410 | } |
411 | EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all); |
412 | |
413 | /** |
414 | * snd_pcm_lib_malloc_pages - allocate the DMA buffer |
415 | * @substream: the substream to allocate the DMA buffer to |
416 | * @size: the requested buffer size in bytes |
417 | * |
418 | * Allocates the DMA buffer on the BUS type given earlier to |
419 | * snd_pcm_lib_preallocate_xxx_pages(). |
420 | * |
421 | * Return: 1 if the buffer is changed, 0 if not changed, or a negative |
422 | * code on failure. |
423 | */ |
424 | int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size) |
425 | { |
426 | struct snd_card *card; |
427 | struct snd_pcm_runtime *runtime; |
428 | struct snd_dma_buffer *dmab = NULL; |
429 | |
430 | if (PCM_RUNTIME_CHECK(substream)) |
431 | return -EINVAL; |
432 | if (snd_BUG_ON(substream->dma_buffer.dev.type == |
433 | SNDRV_DMA_TYPE_UNKNOWN)) |
434 | return -EINVAL; |
435 | runtime = substream->runtime; |
436 | card = substream->pcm->card; |
437 | |
438 | if (runtime->dma_buffer_p) { |
439 | /* perphaps, we might free the large DMA memory region |
440 | to save some space here, but the actual solution |
441 | costs us less time */ |
442 | if (runtime->dma_buffer_p->bytes >= size) { |
443 | runtime->dma_bytes = size; |
444 | return 0; /* ok, do not change */ |
445 | } |
446 | snd_pcm_lib_free_pages(substream); |
447 | } |
448 | if (substream->dma_buffer.area != NULL && |
449 | substream->dma_buffer.bytes >= size) { |
450 | dmab = &substream->dma_buffer; /* use the pre-allocated buffer */ |
451 | } else { |
452 | /* dma_max=0 means the fixed size preallocation */ |
453 | if (substream->dma_buffer.area && !substream->dma_max) |
454 | return -ENOMEM; |
455 | dmab = kzalloc(size: sizeof(*dmab), GFP_KERNEL); |
456 | if (! dmab) |
457 | return -ENOMEM; |
458 | dmab->dev = substream->dma_buffer.dev; |
459 | if (do_alloc_pages(card, |
460 | type: substream->dma_buffer.dev.type, |
461 | dev: substream->dma_buffer.dev.dev, |
462 | str: substream->stream, |
463 | size, dmab) < 0) { |
464 | kfree(objp: dmab); |
465 | pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n" , |
466 | substream->pcm->card->number, substream->pcm->device, |
467 | substream->stream ? 'c' : 'p', substream->number, |
468 | substream->pcm->name, size); |
469 | return -ENOMEM; |
470 | } |
471 | } |
472 | snd_pcm_set_runtime_buffer(substream, bufp: dmab); |
473 | runtime->dma_bytes = size; |
474 | return 1; /* area was changed */ |
475 | } |
476 | EXPORT_SYMBOL(snd_pcm_lib_malloc_pages); |
477 | |
478 | /** |
479 | * snd_pcm_lib_free_pages - release the allocated DMA buffer. |
480 | * @substream: the substream to release the DMA buffer |
481 | * |
482 | * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages(). |
483 | * |
484 | * Return: Zero if successful, or a negative error code on failure. |
485 | */ |
486 | int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream) |
487 | { |
488 | struct snd_pcm_runtime *runtime; |
489 | |
490 | if (PCM_RUNTIME_CHECK(substream)) |
491 | return -EINVAL; |
492 | runtime = substream->runtime; |
493 | if (runtime->dma_area == NULL) |
494 | return 0; |
495 | if (runtime->dma_buffer_p != &substream->dma_buffer) { |
496 | struct snd_card *card = substream->pcm->card; |
497 | |
498 | /* it's a newly allocated buffer. release it now. */ |
499 | do_free_pages(card, dmab: runtime->dma_buffer_p); |
500 | kfree(objp: runtime->dma_buffer_p); |
501 | } |
502 | snd_pcm_set_runtime_buffer(substream, NULL); |
503 | return 0; |
504 | } |
505 | EXPORT_SYMBOL(snd_pcm_lib_free_pages); |
506 | |
507 | int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream, |
508 | size_t size, gfp_t gfp_flags) |
509 | { |
510 | struct snd_pcm_runtime *runtime; |
511 | |
512 | if (PCM_RUNTIME_CHECK(substream)) |
513 | return -EINVAL; |
514 | runtime = substream->runtime; |
515 | if (runtime->dma_area) { |
516 | if (runtime->dma_bytes >= size) |
517 | return 0; /* already large enough */ |
518 | vfree(addr: runtime->dma_area); |
519 | } |
520 | runtime->dma_area = __vmalloc(size, gfp_mask: gfp_flags); |
521 | if (!runtime->dma_area) |
522 | return -ENOMEM; |
523 | runtime->dma_bytes = size; |
524 | return 1; |
525 | } |
526 | EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer); |
527 | |
528 | /** |
529 | * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer |
530 | * @substream: the substream with a buffer allocated by |
531 | * snd_pcm_lib_alloc_vmalloc_buffer() |
532 | * |
533 | * Return: Zero if successful, or a negative error code on failure. |
534 | */ |
535 | int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream) |
536 | { |
537 | struct snd_pcm_runtime *runtime; |
538 | |
539 | if (PCM_RUNTIME_CHECK(substream)) |
540 | return -EINVAL; |
541 | runtime = substream->runtime; |
542 | vfree(addr: runtime->dma_area); |
543 | runtime->dma_area = NULL; |
544 | return 0; |
545 | } |
546 | EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer); |
547 | |
548 | /** |
549 | * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct |
550 | * @substream: the substream with a buffer allocated by |
551 | * snd_pcm_lib_alloc_vmalloc_buffer() |
552 | * @offset: offset in the buffer |
553 | * |
554 | * This function is to be used as the page callback in the PCM ops. |
555 | * |
556 | * Return: The page struct, or %NULL on failure. |
557 | */ |
558 | struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream, |
559 | unsigned long offset) |
560 | { |
561 | return vmalloc_to_page(addr: substream->runtime->dma_area + offset); |
562 | } |
563 | EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page); |
564 | |