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Linux/sound/core/pcm_memory.c

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

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