sound/core/memalloc.c

   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 <linux/dma-mapping.h>
  32 #include <linux/moduleparam.h>
  33 #include <asm/semaphore.h>
  34 #include <sound/memalloc.h>
  35 #ifdef CONFIG_SBUS
  36 #include <asm/sbus.h>
  37 #endif
  38
  39
  40 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@suse.cz>");
  41 MODULE_DESCRIPTION("Memory allocator for ALSA system.");
  42 MODULE_LICENSE("GPL");
  43
  44
  45 #ifndef SNDRV_CARDS
  46 #define SNDRV_CARDS     8
  47 #endif
  48
  49 /* FIXME: so far only some PCI devices have the preallocation table */
  50 #ifdef CONFIG_PCI
  51 static int enable[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = 1};
  52 module_param_array(enable, bool, NULL, 0444);
  53 MODULE_PARM_DESC(enable, "Enable cards to allocate buffers.");
  54 #endif
  55
  56 /*
  57  */
  58
  59 void *snd_malloc_sgbuf_pages(struct device *device,
  60                              size_t size, struct snd_dma_buffer *dmab,
  61                              size_t *res_size);
  62 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab);
  63
  64 /*
  65  */
  66
  67 static DECLARE_MUTEX(list_mutex);
  68 static LIST_HEAD(mem_list_head);
  69
  70 /* buffer preservation list */
  71 struct snd_mem_list {
  72         struct snd_dma_buffer buffer;
  73         unsigned int id;
  74         struct list_head list;
  75 };
  76
  77 /* id for pre-allocated buffers */
  78 #define SNDRV_DMA_DEVICE_UNUSED (unsigned int)-1
  79
  80 #ifdef CONFIG_SND_DEBUG
  81 #define __ASTRING__(x) #x
  82 #define snd_assert(expr, args...) do {\
  83         if (!(expr)) {\
  84                 printk(KERN_ERR "snd-malloc: BUG? (%s) (called from %p)\n", __ASTRING__(expr), __builtin_return_address(0));\
  85                 args;\
  86         }\
  87 } while (0)
  88 #else
  89 #define snd_assert(expr, args...) /**/
  90 #endif
  91
  92 /*
  93  *  Hacks
  94  */
  95
  96 #if defined(__i386__) || defined(__ppc__) || defined(__x86_64__)
  97 /*
  98  * A hack to allocate large buffers via dma_alloc_coherent()
  99  *
 100  * since dma_alloc_coherent always tries GFP_DMA when the requested
 101  * pci memory region is below 32bit, it happens quite often that even
 102  * 2 order of pages cannot be allocated.
 103  *
 104  * so in the following, we allocate at first without dma_mask, so that
 105  * allocation will be done without GFP_DMA.  if the area doesn't match
 106  * with the requested region, then realloate with the original dma_mask
 107  * again.
 108  *
 109  * Really, we want to move this type of thing into dma_alloc_coherent()
 110  * so dma_mask doesn't have to be messed with.
 111  */
 112
 113 static void *snd_dma_hack_alloc_coherent(struct device *dev, size_t size,
 114                                          dma_addr_t *dma_handle, int flags)
 115 {
 116         void *ret;
 117         u64 dma_mask, coherent_dma_mask;
 118
 119         if (dev == NULL || !dev->dma_mask)
 120                 return dma_alloc_coherent(dev, size, dma_handle, flags);
 121         dma_mask = *dev->dma_mask;
 122         coherent_dma_mask = dev->coherent_dma_mask;
 123         *dev->dma_mask = 0xffffffff;    /* do without masking */
 124         dev->coherent_dma_mask = 0xffffffff;    /* do without masking */
 125         ret = dma_alloc_coherent(dev, size, dma_handle, flags);
 126         *dev->dma_mask = dma_mask;      /* restore */
 127         dev->coherent_dma_mask = coherent_dma_mask;     /* restore */
 128         if (ret) {
 129                 /* obtained address is out of range? */
 130                 if (((unsigned long)*dma_handle + size - 1) & ~dma_mask) {
 131                         /* reallocate with the proper mask */
 132                         dma_free_coherent(dev, size, ret, *dma_handle);
 133                         ret = dma_alloc_coherent(dev, size, dma_handle, flags);
 134                 }
 135         } else {
 136                 /* wish to success now with the proper mask... */
 137                 if (dma_mask != 0xffffffffUL) {
 138                         /* allocation with GFP_ATOMIC to avoid the long stall */
 139                         flags &= ~GFP_KERNEL;
 140                         flags |= GFP_ATOMIC;
 141                         ret = dma_alloc_coherent(dev, size, dma_handle, flags);
 142                 }
 143         }
 144         return ret;
 145 }
 146
 147 /* redefine dma_alloc_coherent for some architectures */
 148 #undef dma_alloc_coherent
 149 #define dma_alloc_coherent snd_dma_hack_alloc_coherent
 150
 151 #endif /* arch */
 152
 153 #if ! defined(__arm__)
 154 #define NEED_RESERVE_PAGES
 155 #endif
 156
 157 /*
 158  *
 159  *  Generic memory allocators
 160  *
 161  */
 162
 163 static long snd_allocated_pages; /* holding the number of allocated pages */
 164
 165 static inline void inc_snd_pages(int order)
 166 {
 167         snd_allocated_pages += 1 << order;
 168 }
 169
 170 static inline void dec_snd_pages(int order)
 171 {
 172         snd_allocated_pages -= 1 << order;
 173 }
 174
 175 static void mark_pages(struct page *page, int order)
 176 {
 177         struct page *last_page = page + (1 << order);
 178         while (page < last_page)
 179                 SetPageReserved(page++);
 180 }
 181
 182 static void unmark_pages(struct page *page, int order)
 183 {
 184         struct page *last_page = page + (1 << order);
 185         while (page < last_page)
 186                 ClearPageReserved(page++);
 187 }
 188
 189 /**
 190  * snd_malloc_pages - allocate pages with the given size
 191  * @size: the size to allocate in bytes
 192  * @gfp_flags: the allocation conditions, GFP_XXX
 193  *
 194  * Allocates the physically contiguous pages with the given size.
 195  *
 196  * Returns the pointer of the buffer, or NULL if no enoguh memory.
 197  */
 198 void *snd_malloc_pages(size_t size, unsigned int gfp_flags)
 199 {
 200         int pg;
 201         void *res;
 202
 203         snd_assert(size > 0, return NULL);
 204         snd_assert(gfp_flags != 0, return NULL);
 205         pg = get_order(size);
 206         if ((res = (void *) __get_free_pages(gfp_flags, pg)) != NULL) {
 207                 mark_pages(virt_to_page(res), pg);
 208                 inc_snd_pages(pg);
 209         }
 210         return res;
 211 }
 212
 213 /**
 214  * snd_free_pages - release the pages
 215  * @ptr: the buffer pointer to release
 216  * @size: the allocated buffer size
 217  *
 218  * Releases the buffer allocated via snd_malloc_pages().
 219  */
 220 void snd_free_pages(void *ptr, size_t size)
 221 {
 222         int pg;
 223
 224         if (ptr == NULL)
 225                 return;
 226         pg = get_order(size);
 227         dec_snd_pages(pg);
 228         unmark_pages(virt_to_page(ptr), pg);
 229         free_pages((unsigned long) ptr, pg);
 230 }
 231
 232 /*
 233  *
 234  *  Bus-specific memory allocators
 235  *
 236  */
 237
 238 /* allocate the coherent DMA pages */
 239 static void *snd_malloc_dev_pages(struct device *dev, size_t size, dma_addr_t *dma)
 240 {
 241         int pg;
 242         void *res;
 243         unsigned int gfp_flags;
 244
 245         snd_assert(size > 0, return NULL);
 246         snd_assert(dma != NULL, return NULL);
 247         pg = get_order(size);
 248         gfp_flags = GFP_KERNEL
 249                 | __GFP_NORETRY /* don't trigger OOM-killer */
 250                 | __GFP_NOWARN; /* no stack trace print - this call is non-critical */
 251         res = dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags);
 252         if (res != NULL) {
 253 #ifdef NEED_RESERVE_PAGES
 254                 mark_pages(virt_to_page(res), pg); /* should be dma_to_page() */
 255 #endif
 256                 inc_snd_pages(pg);
 257         }
 258
 259         return res;
 260 }
 261
 262 /* free the coherent DMA pages */
 263 static void snd_free_dev_pages(struct device *dev, size_t size, void *ptr,
 264                                dma_addr_t dma)
 265 {
 266         int pg;
 267
 268         if (ptr == NULL)
 269                 return;
 270         pg = get_order(size);
 271         dec_snd_pages(pg);
 272 #ifdef NEED_RESERVE_PAGES
 273         unmark_pages(virt_to_page(ptr), pg); /* should be dma_to_page() */
 274 #endif
 275         dma_free_coherent(dev, PAGE_SIZE << pg, ptr, dma);
 276 }
 277
 278 #ifdef CONFIG_SBUS
 279
 280 static void *snd_malloc_sbus_pages(struct device *dev, size_t size,
 281                                    dma_addr_t *dma_addr)
 282 {
 283         struct sbus_dev *sdev = (struct sbus_dev *)dev;
 284         int pg;
 285         void *res;
 286
 287         snd_assert(size > 0, return NULL);
 288         snd_assert(dma_addr != NULL, return NULL);
 289         pg = get_order(size);
 290         res = sbus_alloc_consistent(sdev, PAGE_SIZE * (1 << pg), dma_addr);
 291         if (res != NULL)
 292                 inc_snd_pages(pg);
 293         return res;
 294 }
 295
 296 static void snd_free_sbus_pages(struct device *dev, size_t size,
 297                                 void *ptr, dma_addr_t dma_addr)
 298 {
 299         struct sbus_dev *sdev = (struct sbus_dev *)dev;
 300         int pg;
 301
 302         if (ptr == NULL)
 303                 return;
 304         pg = get_order(size);
 305         dec_snd_pages(pg);
 306         sbus_free_consistent(sdev, PAGE_SIZE * (1 << pg), ptr, dma_addr);
 307 }
 308
 309 #endif /* CONFIG_SBUS */
 310
 311 /*
 312  *
 313  *  ALSA generic memory management
 314  *
 315  */
 316
 317
 318 /**
 319  * snd_dma_alloc_pages - allocate the buffer area according to the given type
 320  * @type: the DMA buffer type
 321  * @device: the device pointer
 322  * @size: the buffer size to allocate
 323  * @dmab: buffer allocation record to store the allocated data
 324  *
 325  * Calls the memory-allocator function for the corresponding
 326  * buffer type.
 327  *
 328  * Returns zero if the buffer with the given size is allocated successfuly,
 329  * other a negative value at error.
 330  */
 331 int snd_dma_alloc_pages(int type, struct device *device, size_t size,
 332                         struct snd_dma_buffer *dmab)
 333 {
 334         snd_assert(size > 0, return -ENXIO);
 335         snd_assert(dmab != NULL, return -ENXIO);
 336
 337         dmab->dev.type = type;
 338         dmab->dev.dev = device;
 339         dmab->bytes = 0;
 340         switch (type) {
 341         case SNDRV_DMA_TYPE_CONTINUOUS:
 342                 dmab->area = snd_malloc_pages(size, (unsigned long)device);
 343                 dmab->addr = 0;
 344                 break;
 345 #ifdef CONFIG_SBUS
 346         case SNDRV_DMA_TYPE_SBUS:
 347                 dmab->area = snd_malloc_sbus_pages(device, size, &dmab->addr);
 348                 break;
 349 #endif
 350         case SNDRV_DMA_TYPE_DEV:
 351                 dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
 352                 break;
 353         case SNDRV_DMA_TYPE_DEV_SG:
 354                 snd_malloc_sgbuf_pages(device, size, dmab, NULL);
 355                 break;
 356         default:
 357                 printk(KERN_ERR "snd-malloc: invalid device type %d\n", type);
 358                 dmab->area = NULL;
 359                 dmab->addr = 0;
 360                 return -ENXIO;
 361         }
 362         if (! dmab->area)
 363                 return -ENOMEM;
 364         dmab->bytes = size;
 365         return 0;
 366 }
 367
 368 /**
 369  * snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
 370  * @type: the DMA buffer type
 371  * @device: the device pointer
 372  * @size: the buffer size to allocate
 373  * @dmab: buffer allocation record to store the allocated data
 374  *
 375  * Calls the memory-allocator function for the corresponding
 376  * buffer type.  When no space is left, this function reduces the size and
 377  * tries to allocate again.  The size actually allocated is stored in
 378  * res_size argument.
 379  *
 380  * Returns zero if the buffer with the given size is allocated successfuly,
 381  * other a negative value at error.
 382  */
 383 int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
 384                                  struct snd_dma_buffer *dmab)
 385 {
 386         int err;
 387
 388         snd_assert(size > 0, return -ENXIO);
 389         snd_assert(dmab != NULL, return -ENXIO);
 390
 391         while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
 392                 if (err != -ENOMEM)
 393                         return err;
 394                 size >>= 1;
 395                 if (size <= PAGE_SIZE)
 396                         return -ENOMEM;
 397         }
 398         if (! dmab->area)
 399                 return -ENOMEM;
 400         return 0;
 401 }
 402
 403
 404 /**
 405  * snd_dma_free_pages - release the allocated buffer
 406  * @dmab: the buffer allocation record to release
 407  *
 408  * Releases the allocated buffer via snd_dma_alloc_pages().
 409  */
 410 void snd_dma_free_pages(struct snd_dma_buffer *dmab)
 411 {
 412         switch (dmab->dev.type) {
 413         case SNDRV_DMA_TYPE_CONTINUOUS:
 414                 snd_free_pages(dmab->area, dmab->bytes);
 415                 break;
 416 #ifdef CONFIG_SBUS
 417         case SNDRV_DMA_TYPE_SBUS:
 418                 snd_free_sbus_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
 419                 break;
 420 #endif
 421         case SNDRV_DMA_TYPE_DEV:
 422                 snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
 423                 break;
 424         case SNDRV_DMA_TYPE_DEV_SG:
 425                 snd_free_sgbuf_pages(dmab);
 426                 break;
 427         default:
 428                 printk(KERN_ERR "snd-malloc: invalid device type %d\n", dmab->dev.type);
 429         }
 430 }
 431
 432
 433 /**
 434  * snd_dma_get_reserved - get the reserved buffer for the given device
 435  * @dmab: the buffer allocation record to store
 436  * @id: the buffer id
 437  *
 438  * Looks for the reserved-buffer list and re-uses if the same buffer
 439  * is found in the list.  When the buffer is found, it's removed from the free list.
 440  *
 441  * Returns the size of buffer if the buffer is found, or zero if not found.
 442  */
 443 size_t snd_dma_get_reserved_buf(struct snd_dma_buffer *dmab, unsigned int id)
 444 {
 445         struct list_head *p;
 446         struct snd_mem_list *mem;
 447
 448         snd_assert(dmab, return 0);
 449
 450         down(&list_mutex);
 451         list_for_each(p, &mem_list_head) {
 452                 mem = list_entry(p, struct snd_mem_list, list);
 453                 if (mem->id == id &&
 454                     ! memcmp(&mem->buffer.dev, &dmab->dev, sizeof(dmab->dev))) {
 455                         list_del(p);
 456                         *dmab = mem->buffer;
 457                         kfree(mem);
 458                         up(&list_mutex);
 459                         return dmab->bytes;
 460                 }
 461         }
 462         up(&list_mutex);
 463         return 0;
 464 }
 465
 466 /**
 467  * snd_dma_reserve_buf - reserve the buffer
 468  * @dmab: the buffer to reserve
 469  * @id: the buffer id
 470  *
 471  * Reserves the given buffer as a reserved buffer.
 472  *
 473  * Returns zero if successful, or a negative code at error.
 474  */
 475 int snd_dma_reserve_buf(struct snd_dma_buffer *dmab, unsigned int id)
 476 {
 477         struct snd_mem_list *mem;
 478
 479         snd_assert(dmab, return -EINVAL);
 480         mem = kmalloc(sizeof(*mem), GFP_KERNEL);
 481         if (! mem)
 482                 return -ENOMEM;
 483         down(&list_mutex);
 484         mem->buffer = *dmab;
 485         mem->id = id;
 486         list_add_tail(&mem->list, &mem_list_head);
 487         up(&list_mutex);
 488         return 0;
 489 }
 490
 491 /*
 492  * purge all reserved buffers
 493  */
 494 static void free_all_reserved_pages(void)
 495 {
 496         struct list_head *p;
 497         struct snd_mem_list *mem;
 498
 499         down(&list_mutex);
 500         while (! list_empty(&mem_list_head)) {
 501                 p = mem_list_head.next;
 502                 mem = list_entry(p, struct snd_mem_list, list);
 503                 list_del(p);
 504                 snd_dma_free_pages(&mem->buffer);
 505                 kfree(mem);
 506         }
 507         up(&list_mutex);
 508 }
 509
 510
 511
 512 /*
 513  * allocation of buffers for pre-defined devices
 514  */
 515
 516 #ifdef CONFIG_PCI
 517 /* FIXME: for pci only - other bus? */
 518 struct prealloc_dev {
 519         unsigned short vendor;
 520         unsigned short device;
 521         unsigned long dma_mask;
 522         unsigned int size;
 523         unsigned int buffers;
 524 };
 525
 526 #define HAMMERFALL_BUFFER_SIZE    (16*1024*4*(26+1)+0x10000)
 527
 528 static struct prealloc_dev prealloc_devices[] __initdata = {
 529         {
 530                 /* hammerfall */
 531                 .vendor = 0x10ee,
 532                 .device = 0x3fc4,
 533                 .dma_mask = 0xffffffff,
 534                 .size = HAMMERFALL_BUFFER_SIZE,
 535                 .buffers = 2
 536         },
 537         {
 538                 /* HDSP */
 539                 .vendor = 0x10ee,
 540                 .device = 0x3fc5,
 541                 .dma_mask = 0xffffffff,
 542                 .size = HAMMERFALL_BUFFER_SIZE,
 543                 .buffers = 2
 544         },
 545         { }, /* terminator */
 546 };
 547
 548 static void __init preallocate_cards(void)
 549 {
 550         struct pci_dev *pci = NULL;
 551         int card;
 552
 553         card = 0;
 554
 555         while ((pci = pci_find_device(PCI_ANY_ID, PCI_ANY_ID, pci)) != NULL) {
 556                 struct prealloc_dev *dev;
 557                 unsigned int i;
 558                 if (card >= SNDRV_CARDS)
 559                         break;
 560                 for (dev = prealloc_devices; dev->vendor; dev++) {
 561                         if (dev->vendor == pci->vendor && dev->device == pci->device)
 562                                 break;
 563                 }
 564                 if (! dev->vendor)
 565                         continue;
 566                 if (! enable[card++]) {
 567                         printk(KERN_DEBUG "snd-page-alloc: skipping card %d, device %04x:%04x\n", card, pci->vendor, pci->device);
 568                         continue;
 569                 }
 570
 571                 if (pci_set_dma_mask(pci, dev->dma_mask) < 0 ||
 572                     pci_set_consistent_dma_mask(pci, dev->dma_mask) < 0) {
 573                         printk(KERN_ERR "snd-page-alloc: cannot set DMA mask %lx for pci %04x:%04x\n", dev->dma_mask, dev->vendor, dev->device);
 574                         continue;
 575                 }
 576                 for (i = 0; i < dev->buffers; i++) {
 577                         struct snd_dma_buffer dmab;
 578                         memset(&dmab, 0, sizeof(dmab));
 579                         if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(pci),
 580                                                 dev->size, &dmab) < 0)
 581                                 printk(KERN_WARNING "snd-page-alloc: cannot allocate buffer pages (size = %d)\n", dev->size);
 582                         else
 583                                 snd_dma_reserve_buf(&dmab, snd_dma_pci_buf_id(pci));
 584                 }
 585         }
 586 }
 587 #else
 588 #define preallocate_cards()     /* NOP */
 589 #endif
 590
 591
 592 #ifdef CONFIG_PROC_FS
 593 /*
 594  * proc file interface
 595  */
 596 static int snd_mem_proc_read(char *page, char **start, off_t off,
 597                              int count, int *eof, void *data)
 598 {
 599         int len = 0;
 600         long pages = snd_allocated_pages >> (PAGE_SHIFT-12);
 601         struct list_head *p;
 602         struct snd_mem_list *mem;
 603         int devno;
 604         static char *types[] = { "UNKNOWN", "CONT", "DEV", "DEV-SG", "SBUS" };
 605
 606         down(&list_mutex);
 607         len += snprintf(page + len, count - len,
 608                         "pages  : %li bytes (%li pages per %likB)\n",
 609                         pages * PAGE_SIZE, pages, PAGE_SIZE / 1024);
 610         devno = 0;
 611         list_for_each(p, &mem_list_head) {
 612                 mem = list_entry(p, struct snd_mem_list, list);
 613                 devno++;
 614                 len += snprintf(page + len, count - len,
 615                                 "buffer %d : ID %08x : type %s\n",
 616                                 devno, mem->id, types[mem->buffer.dev.type]);
 617                 len += snprintf(page + len, count - len,
 618                                 "  addr = 0x%lx, size = %d bytes\n",
 619                                 (unsigned long)mem->buffer.addr, (int)mem->buffer.bytes);
 620         }
 621         up(&list_mutex);
 622         return len;
 623 }
 624 #endif /* CONFIG_PROC_FS */
 625
 626 /*
 627  * module entry
 628  */
 629
 630 static int __init snd_mem_init(void)
 631 {
 632 #ifdef CONFIG_PROC_FS
 633         create_proc_read_entry("driver/snd-page-alloc", 0, NULL, snd_mem_proc_read, NULL);
 634 #endif
 635         preallocate_cards();
 636         return 0;
 637 }
 638
 639 static void __exit snd_mem_exit(void)
 640 {
 641         remove_proc_entry("driver/snd-page-alloc", NULL);
 642         free_all_reserved_pages();
 643         if (snd_allocated_pages > 0)
 644                 printk(KERN_ERR "snd-malloc: Memory leak?  pages not freed = %li\n", snd_allocated_pages);
 645 }
 646
 647
 648 module_init(snd_mem_init)
 649 module_exit(snd_mem_exit)
 650
 651
 652 /*
 653  * exports
 654  */
 655 EXPORT_SYMBOL(snd_dma_alloc_pages);
 656 EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
 657 EXPORT_SYMBOL(snd_dma_free_pages);
 658
 659 EXPORT_SYMBOL(snd_dma_get_reserved_buf);
 660 EXPORT_SYMBOL(snd_dma_reserve_buf);
 661
 662 EXPORT_SYMBOL(snd_malloc_pages);
 663 EXPORT_SYMBOL(snd_free_pages);