xref: /linux/sound/core/memalloc.c (revision 9ce7677cfd7cd871adb457c80bea3b581b839641)
1 /*
2  *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
3  *                   Takashi Iwai <tiwai@suse.de>
4  *
5  *  Generic memory allocators
6  *
7  *
8  *   This program is free software; you can redistribute it and/or modify
9  *   it under the terms of the GNU General Public License as published by
10  *   the Free Software Foundation; either version 2 of the License, or
11  *   (at your option) any later version.
12  *
13  *   This program is distributed in the hope that it will be useful,
14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *   GNU General Public License for more details.
17  *
18  *   You should have received a copy of the GNU General Public License
19  *   along with this program; if not, write to the Free Software
20  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
21  *
22  */
23 
24 #include <linux/config.h>
25 #include <linux/module.h>
26 #include <linux/proc_fs.h>
27 #include <linux/init.h>
28 #include <linux/pci.h>
29 #include <linux/slab.h>
30 #include <linux/mm.h>
31 #include <asm/uaccess.h>
32 #include <linux/dma-mapping.h>
33 #include <linux/moduleparam.h>
34 #include <asm/semaphore.h>
35 #include <sound/memalloc.h>
36 #ifdef CONFIG_SBUS
37 #include <asm/sbus.h>
38 #endif
39 
40 
41 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@suse.cz>");
42 MODULE_DESCRIPTION("Memory allocator for ALSA system.");
43 MODULE_LICENSE("GPL");
44 
45 
46 #ifndef SNDRV_CARDS
47 #define SNDRV_CARDS	8
48 #endif
49 
50 /*
51  */
52 
53 void *snd_malloc_sgbuf_pages(struct device *device,
54                              size_t size, struct snd_dma_buffer *dmab,
55 			     size_t *res_size);
56 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab);
57 
58 /*
59  */
60 
61 static DECLARE_MUTEX(list_mutex);
62 static LIST_HEAD(mem_list_head);
63 
64 /* buffer preservation list */
65 struct snd_mem_list {
66 	struct snd_dma_buffer buffer;
67 	unsigned int id;
68 	struct list_head list;
69 };
70 
71 /* id for pre-allocated buffers */
72 #define SNDRV_DMA_DEVICE_UNUSED (unsigned int)-1
73 
74 #ifdef CONFIG_SND_DEBUG
75 #define __ASTRING__(x) #x
76 #define snd_assert(expr, args...) do {\
77 	if (!(expr)) {\
78 		printk(KERN_ERR "snd-malloc: BUG? (%s) (called from %p)\n", __ASTRING__(expr), __builtin_return_address(0));\
79 		args;\
80 	}\
81 } while (0)
82 #else
83 #define snd_assert(expr, args...) /**/
84 #endif
85 
86 /*
87  *  Hacks
88  */
89 
90 #if defined(__i386__) || defined(__ppc__) || defined(__x86_64__)
91 /*
92  * A hack to allocate large buffers via dma_alloc_coherent()
93  *
94  * since dma_alloc_coherent always tries GFP_DMA when the requested
95  * pci memory region is below 32bit, it happens quite often that even
96  * 2 order of pages cannot be allocated.
97  *
98  * so in the following, we allocate at first without dma_mask, so that
99  * allocation will be done without GFP_DMA.  if the area doesn't match
100  * with the requested region, then realloate with the original dma_mask
101  * again.
102  *
103  * Really, we want to move this type of thing into dma_alloc_coherent()
104  * so dma_mask doesn't have to be messed with.
105  */
106 
107 static void *snd_dma_hack_alloc_coherent(struct device *dev, size_t size,
108 					 dma_addr_t *dma_handle,
109 					 gfp_t flags)
110 {
111 	void *ret;
112 	u64 dma_mask, coherent_dma_mask;
113 
114 	if (dev == NULL || !dev->dma_mask)
115 		return dma_alloc_coherent(dev, size, dma_handle, flags);
116 	dma_mask = *dev->dma_mask;
117 	coherent_dma_mask = dev->coherent_dma_mask;
118 	*dev->dma_mask = 0xffffffff; 	/* do without masking */
119 	dev->coherent_dma_mask = 0xffffffff; 	/* do without masking */
120 	ret = dma_alloc_coherent(dev, size, dma_handle, flags);
121 	*dev->dma_mask = dma_mask;	/* restore */
122 	dev->coherent_dma_mask = coherent_dma_mask;	/* restore */
123 	if (ret) {
124 		/* obtained address is out of range? */
125 		if (((unsigned long)*dma_handle + size - 1) & ~dma_mask) {
126 			/* reallocate with the proper mask */
127 			dma_free_coherent(dev, size, ret, *dma_handle);
128 			ret = dma_alloc_coherent(dev, size, dma_handle, flags);
129 		}
130 	} else {
131 		/* wish to success now with the proper mask... */
132 		if (dma_mask != 0xffffffffUL) {
133 			/* allocation with GFP_ATOMIC to avoid the long stall */
134 			flags &= ~GFP_KERNEL;
135 			flags |= GFP_ATOMIC;
136 			ret = dma_alloc_coherent(dev, size, dma_handle, flags);
137 		}
138 	}
139 	return ret;
140 }
141 
142 /* redefine dma_alloc_coherent for some architectures */
143 #undef dma_alloc_coherent
144 #define dma_alloc_coherent snd_dma_hack_alloc_coherent
145 
146 #endif /* arch */
147 
148 #if ! defined(__arm__)
149 #define NEED_RESERVE_PAGES
150 #endif
151 
152 /*
153  *
154  *  Generic memory allocators
155  *
156  */
157 
158 static long snd_allocated_pages; /* holding the number of allocated pages */
159 
160 static inline void inc_snd_pages(int order)
161 {
162 	snd_allocated_pages += 1 << order;
163 }
164 
165 static inline void dec_snd_pages(int order)
166 {
167 	snd_allocated_pages -= 1 << order;
168 }
169 
170 static void mark_pages(struct page *page, int order)
171 {
172 	struct page *last_page = page + (1 << order);
173 	while (page < last_page)
174 		SetPageReserved(page++);
175 }
176 
177 static void unmark_pages(struct page *page, int order)
178 {
179 	struct page *last_page = page + (1 << order);
180 	while (page < last_page)
181 		ClearPageReserved(page++);
182 }
183 
184 /**
185  * snd_malloc_pages - allocate pages with the given size
186  * @size: the size to allocate in bytes
187  * @gfp_flags: the allocation conditions, GFP_XXX
188  *
189  * Allocates the physically contiguous pages with the given size.
190  *
191  * Returns the pointer of the buffer, or NULL if no enoguh memory.
192  */
193 void *snd_malloc_pages(size_t size, gfp_t gfp_flags)
194 {
195 	int pg;
196 	void *res;
197 
198 	snd_assert(size > 0, return NULL);
199 	snd_assert(gfp_flags != 0, return NULL);
200 	gfp_flags |= __GFP_COMP;	/* compound page lets parts be mapped */
201 	pg = get_order(size);
202 	if ((res = (void *) __get_free_pages(gfp_flags, pg)) != NULL) {
203 		mark_pages(virt_to_page(res), pg);
204 		inc_snd_pages(pg);
205 	}
206 	return res;
207 }
208 
209 /**
210  * snd_free_pages - release the pages
211  * @ptr: the buffer pointer to release
212  * @size: the allocated buffer size
213  *
214  * Releases the buffer allocated via snd_malloc_pages().
215  */
216 void snd_free_pages(void *ptr, size_t size)
217 {
218 	int pg;
219 
220 	if (ptr == NULL)
221 		return;
222 	pg = get_order(size);
223 	dec_snd_pages(pg);
224 	unmark_pages(virt_to_page(ptr), pg);
225 	free_pages((unsigned long) ptr, pg);
226 }
227 
228 /*
229  *
230  *  Bus-specific memory allocators
231  *
232  */
233 
234 /* allocate the coherent DMA pages */
235 static void *snd_malloc_dev_pages(struct device *dev, size_t size, dma_addr_t *dma)
236 {
237 	int pg;
238 	void *res;
239 	gfp_t gfp_flags;
240 
241 	snd_assert(size > 0, return NULL);
242 	snd_assert(dma != NULL, return NULL);
243 	pg = get_order(size);
244 	gfp_flags = GFP_KERNEL
245 		| __GFP_COMP	/* compound page lets parts be mapped */
246 		| __GFP_NORETRY /* don't trigger OOM-killer */
247 		| __GFP_NOWARN; /* no stack trace print - this call is non-critical */
248 	res = dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags);
249 	if (res != NULL) {
250 #ifdef NEED_RESERVE_PAGES
251 		mark_pages(virt_to_page(res), pg); /* should be dma_to_page() */
252 #endif
253 		inc_snd_pages(pg);
254 	}
255 
256 	return res;
257 }
258 
259 /* free the coherent DMA pages */
260 static void snd_free_dev_pages(struct device *dev, size_t size, void *ptr,
261 			       dma_addr_t dma)
262 {
263 	int pg;
264 
265 	if (ptr == NULL)
266 		return;
267 	pg = get_order(size);
268 	dec_snd_pages(pg);
269 #ifdef NEED_RESERVE_PAGES
270 	unmark_pages(virt_to_page(ptr), pg); /* should be dma_to_page() */
271 #endif
272 	dma_free_coherent(dev, PAGE_SIZE << pg, ptr, dma);
273 }
274 
275 #ifdef CONFIG_SBUS
276 
277 static void *snd_malloc_sbus_pages(struct device *dev, size_t size,
278 				   dma_addr_t *dma_addr)
279 {
280 	struct sbus_dev *sdev = (struct sbus_dev *)dev;
281 	int pg;
282 	void *res;
283 
284 	snd_assert(size > 0, return NULL);
285 	snd_assert(dma_addr != NULL, return NULL);
286 	pg = get_order(size);
287 	res = sbus_alloc_consistent(sdev, PAGE_SIZE * (1 << pg), dma_addr);
288 	if (res != NULL)
289 		inc_snd_pages(pg);
290 	return res;
291 }
292 
293 static void snd_free_sbus_pages(struct device *dev, size_t size,
294 				void *ptr, dma_addr_t dma_addr)
295 {
296 	struct sbus_dev *sdev = (struct sbus_dev *)dev;
297 	int pg;
298 
299 	if (ptr == NULL)
300 		return;
301 	pg = get_order(size);
302 	dec_snd_pages(pg);
303 	sbus_free_consistent(sdev, PAGE_SIZE * (1 << pg), ptr, dma_addr);
304 }
305 
306 #endif /* CONFIG_SBUS */
307 
308 /*
309  *
310  *  ALSA generic memory management
311  *
312  */
313 
314 
315 /**
316  * snd_dma_alloc_pages - allocate the buffer area according to the given type
317  * @type: the DMA buffer type
318  * @device: the device pointer
319  * @size: the buffer size to allocate
320  * @dmab: buffer allocation record to store the allocated data
321  *
322  * Calls the memory-allocator function for the corresponding
323  * buffer type.
324  *
325  * Returns zero if the buffer with the given size is allocated successfuly,
326  * other a negative value at error.
327  */
328 int snd_dma_alloc_pages(int type, struct device *device, size_t size,
329 			struct snd_dma_buffer *dmab)
330 {
331 	snd_assert(size > 0, return -ENXIO);
332 	snd_assert(dmab != NULL, return -ENXIO);
333 
334 	dmab->dev.type = type;
335 	dmab->dev.dev = device;
336 	dmab->bytes = 0;
337 	switch (type) {
338 	case SNDRV_DMA_TYPE_CONTINUOUS:
339 		dmab->area = snd_malloc_pages(size, (unsigned long)device);
340 		dmab->addr = 0;
341 		break;
342 #ifdef CONFIG_SBUS
343 	case SNDRV_DMA_TYPE_SBUS:
344 		dmab->area = snd_malloc_sbus_pages(device, size, &dmab->addr);
345 		break;
346 #endif
347 	case SNDRV_DMA_TYPE_DEV:
348 		dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
349 		break;
350 	case SNDRV_DMA_TYPE_DEV_SG:
351 		snd_malloc_sgbuf_pages(device, size, dmab, NULL);
352 		break;
353 	default:
354 		printk(KERN_ERR "snd-malloc: invalid device type %d\n", type);
355 		dmab->area = NULL;
356 		dmab->addr = 0;
357 		return -ENXIO;
358 	}
359 	if (! dmab->area)
360 		return -ENOMEM;
361 	dmab->bytes = size;
362 	return 0;
363 }
364 
365 /**
366  * snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
367  * @type: the DMA buffer type
368  * @device: the device pointer
369  * @size: the buffer size to allocate
370  * @dmab: buffer allocation record to store the allocated data
371  *
372  * Calls the memory-allocator function for the corresponding
373  * buffer type.  When no space is left, this function reduces the size and
374  * tries to allocate again.  The size actually allocated is stored in
375  * res_size argument.
376  *
377  * Returns zero if the buffer with the given size is allocated successfuly,
378  * other a negative value at error.
379  */
380 int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
381 				 struct snd_dma_buffer *dmab)
382 {
383 	int err;
384 
385 	snd_assert(size > 0, return -ENXIO);
386 	snd_assert(dmab != NULL, return -ENXIO);
387 
388 	while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
389 		if (err != -ENOMEM)
390 			return err;
391 		size >>= 1;
392 		if (size <= PAGE_SIZE)
393 			return -ENOMEM;
394 	}
395 	if (! dmab->area)
396 		return -ENOMEM;
397 	return 0;
398 }
399 
400 
401 /**
402  * snd_dma_free_pages - release the allocated buffer
403  * @dmab: the buffer allocation record to release
404  *
405  * Releases the allocated buffer via snd_dma_alloc_pages().
406  */
407 void snd_dma_free_pages(struct snd_dma_buffer *dmab)
408 {
409 	switch (dmab->dev.type) {
410 	case SNDRV_DMA_TYPE_CONTINUOUS:
411 		snd_free_pages(dmab->area, dmab->bytes);
412 		break;
413 #ifdef CONFIG_SBUS
414 	case SNDRV_DMA_TYPE_SBUS:
415 		snd_free_sbus_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
416 		break;
417 #endif
418 	case SNDRV_DMA_TYPE_DEV:
419 		snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
420 		break;
421 	case SNDRV_DMA_TYPE_DEV_SG:
422 		snd_free_sgbuf_pages(dmab);
423 		break;
424 	default:
425 		printk(KERN_ERR "snd-malloc: invalid device type %d\n", dmab->dev.type);
426 	}
427 }
428 
429 
430 /**
431  * snd_dma_get_reserved - get the reserved buffer for the given device
432  * @dmab: the buffer allocation record to store
433  * @id: the buffer id
434  *
435  * Looks for the reserved-buffer list and re-uses if the same buffer
436  * is found in the list.  When the buffer is found, it's removed from the free list.
437  *
438  * Returns the size of buffer if the buffer is found, or zero if not found.
439  */
440 size_t snd_dma_get_reserved_buf(struct snd_dma_buffer *dmab, unsigned int id)
441 {
442 	struct list_head *p;
443 	struct snd_mem_list *mem;
444 
445 	snd_assert(dmab, return 0);
446 
447 	down(&list_mutex);
448 	list_for_each(p, &mem_list_head) {
449 		mem = list_entry(p, struct snd_mem_list, list);
450 		if (mem->id == id &&
451 		    (mem->buffer.dev.dev == NULL || dmab->dev.dev == NULL ||
452 		     ! memcmp(&mem->buffer.dev, &dmab->dev, sizeof(dmab->dev)))) {
453 			struct device *dev = dmab->dev.dev;
454 			list_del(p);
455 			*dmab = mem->buffer;
456 			if (dmab->dev.dev == NULL)
457 				dmab->dev.dev = dev;
458 			kfree(mem);
459 			up(&list_mutex);
460 			return dmab->bytes;
461 		}
462 	}
463 	up(&list_mutex);
464 	return 0;
465 }
466 
467 /**
468  * snd_dma_reserve_buf - reserve the buffer
469  * @dmab: the buffer to reserve
470  * @id: the buffer id
471  *
472  * Reserves the given buffer as a reserved buffer.
473  *
474  * Returns zero if successful, or a negative code at error.
475  */
476 int snd_dma_reserve_buf(struct snd_dma_buffer *dmab, unsigned int id)
477 {
478 	struct snd_mem_list *mem;
479 
480 	snd_assert(dmab, return -EINVAL);
481 	mem = kmalloc(sizeof(*mem), GFP_KERNEL);
482 	if (! mem)
483 		return -ENOMEM;
484 	down(&list_mutex);
485 	mem->buffer = *dmab;
486 	mem->id = id;
487 	list_add_tail(&mem->list, &mem_list_head);
488 	up(&list_mutex);
489 	return 0;
490 }
491 
492 /*
493  * purge all reserved buffers
494  */
495 static void free_all_reserved_pages(void)
496 {
497 	struct list_head *p;
498 	struct snd_mem_list *mem;
499 
500 	down(&list_mutex);
501 	while (! list_empty(&mem_list_head)) {
502 		p = mem_list_head.next;
503 		mem = list_entry(p, struct snd_mem_list, list);
504 		list_del(p);
505 		snd_dma_free_pages(&mem->buffer);
506 		kfree(mem);
507 	}
508 	up(&list_mutex);
509 }
510 
511 
512 #ifdef CONFIG_PROC_FS
513 /*
514  * proc file interface
515  */
516 #define SND_MEM_PROC_FILE	"driver/snd-page-alloc"
517 static struct proc_dir_entry *snd_mem_proc;
518 
519 static int snd_mem_proc_read(char *page, char **start, off_t off,
520 			     int count, int *eof, void *data)
521 {
522 	int len = 0;
523 	long pages = snd_allocated_pages >> (PAGE_SHIFT-12);
524 	struct list_head *p;
525 	struct snd_mem_list *mem;
526 	int devno;
527 	static char *types[] = { "UNKNOWN", "CONT", "DEV", "DEV-SG", "SBUS" };
528 
529 	down(&list_mutex);
530 	len += snprintf(page + len, count - len,
531 			"pages  : %li bytes (%li pages per %likB)\n",
532 			pages * PAGE_SIZE, pages, PAGE_SIZE / 1024);
533 	devno = 0;
534 	list_for_each(p, &mem_list_head) {
535 		mem = list_entry(p, struct snd_mem_list, list);
536 		devno++;
537 		len += snprintf(page + len, count - len,
538 				"buffer %d : ID %08x : type %s\n",
539 				devno, mem->id, types[mem->buffer.dev.type]);
540 		len += snprintf(page + len, count - len,
541 				"  addr = 0x%lx, size = %d bytes\n",
542 				(unsigned long)mem->buffer.addr, (int)mem->buffer.bytes);
543 	}
544 	up(&list_mutex);
545 	return len;
546 }
547 
548 /* FIXME: for pci only - other bus? */
549 #ifdef CONFIG_PCI
550 #define gettoken(bufp) strsep(bufp, " \t\n")
551 
552 static int snd_mem_proc_write(struct file *file, const char __user *buffer,
553 			      unsigned long count, void *data)
554 {
555 	char buf[128];
556 	char *token, *p;
557 
558 	if (count > ARRAY_SIZE(buf) - 1)
559 		count = ARRAY_SIZE(buf) - 1;
560 	if (copy_from_user(buf, buffer, count))
561 		return -EFAULT;
562 	buf[ARRAY_SIZE(buf) - 1] = '\0';
563 
564 	p = buf;
565 	token = gettoken(&p);
566 	if (! token || *token == '#')
567 		return (int)count;
568 	if (strcmp(token, "add") == 0) {
569 		char *endp;
570 		int vendor, device, size, buffers;
571 		long mask;
572 		int i, alloced;
573 		struct pci_dev *pci;
574 
575 		if ((token = gettoken(&p)) == NULL ||
576 		    (vendor = simple_strtol(token, NULL, 0)) <= 0 ||
577 		    (token = gettoken(&p)) == NULL ||
578 		    (device = simple_strtol(token, NULL, 0)) <= 0 ||
579 		    (token = gettoken(&p)) == NULL ||
580 		    (mask = simple_strtol(token, NULL, 0)) < 0 ||
581 		    (token = gettoken(&p)) == NULL ||
582 		    (size = memparse(token, &endp)) < 64*1024 ||
583 		    size > 16*1024*1024 /* too big */ ||
584 		    (token = gettoken(&p)) == NULL ||
585 		    (buffers = simple_strtol(token, NULL, 0)) <= 0 ||
586 		    buffers > 4) {
587 			printk(KERN_ERR "snd-page-alloc: invalid proc write format\n");
588 			return (int)count;
589 		}
590 		vendor &= 0xffff;
591 		device &= 0xffff;
592 
593 		alloced = 0;
594 		pci = NULL;
595 		while ((pci = pci_get_device(vendor, device, pci)) != NULL) {
596 			if (mask > 0 && mask < 0xffffffff) {
597 				if (pci_set_dma_mask(pci, mask) < 0 ||
598 				    pci_set_consistent_dma_mask(pci, mask) < 0) {
599 					printk(KERN_ERR "snd-page-alloc: cannot set DMA mask %lx for pci %04x:%04x\n", mask, vendor, device);
600 					return (int)count;
601 				}
602 			}
603 			for (i = 0; i < buffers; i++) {
604 				struct snd_dma_buffer dmab;
605 				memset(&dmab, 0, sizeof(dmab));
606 				if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(pci),
607 							size, &dmab) < 0) {
608 					printk(KERN_ERR "snd-page-alloc: cannot allocate buffer pages (size = %d)\n", size);
609 					pci_dev_put(pci);
610 					return (int)count;
611 				}
612 				snd_dma_reserve_buf(&dmab, snd_dma_pci_buf_id(pci));
613 			}
614 			alloced++;
615 		}
616 		if (! alloced) {
617 			for (i = 0; i < buffers; i++) {
618 				struct snd_dma_buffer dmab;
619 				memset(&dmab, 0, sizeof(dmab));
620 				/* FIXME: We can allocate only in ZONE_DMA
621 				 * without a device pointer!
622 				 */
623 				if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, NULL,
624 							size, &dmab) < 0) {
625 					printk(KERN_ERR "snd-page-alloc: cannot allocate buffer pages (size = %d)\n", size);
626 					break;
627 				}
628 				snd_dma_reserve_buf(&dmab, (unsigned int)((vendor << 16) | device));
629 			}
630 		}
631 	} else if (strcmp(token, "erase") == 0)
632 		/* FIXME: need for releasing each buffer chunk? */
633 		free_all_reserved_pages();
634 	else
635 		printk(KERN_ERR "snd-page-alloc: invalid proc cmd\n");
636 	return (int)count;
637 }
638 #endif /* CONFIG_PCI */
639 #endif /* CONFIG_PROC_FS */
640 
641 /*
642  * module entry
643  */
644 
645 static int __init snd_mem_init(void)
646 {
647 #ifdef CONFIG_PROC_FS
648 	snd_mem_proc = create_proc_entry(SND_MEM_PROC_FILE, 0644, NULL);
649 	if (snd_mem_proc) {
650 		snd_mem_proc->read_proc = snd_mem_proc_read;
651 #ifdef CONFIG_PCI
652 		snd_mem_proc->write_proc = snd_mem_proc_write;
653 #endif
654 	}
655 #endif
656 	return 0;
657 }
658 
659 static void __exit snd_mem_exit(void)
660 {
661 	remove_proc_entry(SND_MEM_PROC_FILE, NULL);
662 	free_all_reserved_pages();
663 	if (snd_allocated_pages > 0)
664 		printk(KERN_ERR "snd-malloc: Memory leak?  pages not freed = %li\n", snd_allocated_pages);
665 }
666 
667 
668 module_init(snd_mem_init)
669 module_exit(snd_mem_exit)
670 
671 
672 /*
673  * exports
674  */
675 EXPORT_SYMBOL(snd_dma_alloc_pages);
676 EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
677 EXPORT_SYMBOL(snd_dma_free_pages);
678 
679 EXPORT_SYMBOL(snd_dma_get_reserved_buf);
680 EXPORT_SYMBOL(snd_dma_reserve_buf);
681 
682 EXPORT_SYMBOL(snd_malloc_pages);
683 EXPORT_SYMBOL(snd_free_pages);
684