mm/swapfile.c

   1 /*
   2  *  linux/mm/swapfile.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   5  *  Swap reorganised 29.12.95, Stephen Tweedie
   6  */
   7
   8 #include <linux/malloc.h>
   9 #include <linux/smp_lock.h>
  10 #include <linux/kernel_stat.h>
  11 #include <linux/swap.h>
  12 #include <linux/swapctl.h>
  13 #include <linux/blkdev.h> /* for blk_size */
  14 #include <linux/vmalloc.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/shm.h>
  17
  18 #include <asm/pgtable.h>
  19
  20 unsigned int nr_swapfiles = 0;
  21
  22 struct swap_list_t swap_list = {-1, -1};
  23
  24 struct swap_info_struct swap_info[MAX_SWAPFILES];
  25
  26 #define SWAPFILE_CLUSTER 256
  27
  28 static inline int scan_swap_map(struct swap_info_struct *si)
  29 {
  30         unsigned long offset;
  31         /*
  32          * We try to cluster swap pages by allocating them
  33          * sequentially in swap.  Once we've allocated
  34          * SWAPFILE_CLUSTER pages this way, however, we resort to
  35          * first-free allocation, starting a new cluster.  This
  36          * prevents us from scattering swap pages all over the entire
  37          * swap partition, so that we reduce overall disk seek times
  38          * between swap pages.  -- sct */
  39         if (si->cluster_nr) {
  40                 while (si->cluster_next <= si->highest_bit) {
  41                         offset = si->cluster_next++;
  42                         if (si->swap_map[offset])
  43                                 continue;
  44                         if (test_bit(offset, si->swap_lockmap))
  45                                 continue;
  46                         si->cluster_nr--;
  47                         goto got_page;
  48                 }
  49         }
  50         si->cluster_nr = SWAPFILE_CLUSTER;
  51         for (offset = si->lowest_bit; offset <= si->highest_bit ; offset++) {
  52                 if (si->swap_map[offset])
  53                         continue;
  54                 if (test_bit(offset, si->swap_lockmap))
  55                         continue;
  56                 si->lowest_bit = offset;
  57 got_page:
  58                 si->swap_map[offset] = 1;
  59                 nr_swap_pages--;
  60                 if (offset == si->highest_bit)
  61                         si->highest_bit--;
  62                 si->cluster_next = offset;
  63                 return offset;
  64         }
  65         return 0;
  66 }
  67
  68 unsigned long get_swap_page(void)
  69 {
  70         struct swap_info_struct * p;
  71         unsigned long offset, entry;
  72         int type, wrapped = 0;
  73
  74         type = swap_list.next;
  75         if (type < 0)
  76                 return 0;
  77         if (nr_swap_pages == 0)
  78                 return 0;
  79
  80         while (1) {
  81                 p = &swap_info[type];
  82                 if ((p->flags & SWP_WRITEOK) == SWP_WRITEOK) {
  83                         offset = scan_swap_map(p);
  84                         if (offset) {
  85                                 entry = SWP_ENTRY(type,offset);
  86                                 type = swap_info[type].next;
  87                                 if (type < 0 ||
  88                                         p->prio != swap_info[type].prio)
  89                                 {
  90                                                 swap_list.next = swap_list.head;
  91                                 }
  92                                 else
  93                                 {
  94                                         swap_list.next = type;
  95                                 }
  96                                 return entry;
  97                         }
  98                 }
  99                 type = p->next;
 100                 if (!wrapped) {
 101                         if (type < 0 || p->prio != swap_info[type].prio) {
 102                                 type = swap_list.head;
 103                                 wrapped = 1;
 104                         }
 105                 } else if (type < 0) {
 106                         return 0;       /* out of swap space */
 107                 }
 108         }
 109 }
 110
 111
 112 void swap_free(unsigned long entry)
 113 {
 114         struct swap_info_struct * p;
 115         unsigned long offset, type;
 116
 117         if (!entry)
 118                 goto out;
 119
 120         type = SWP_TYPE(entry);
 121         if (type & SHM_SWP_TYPE)
 122                 goto out;
 123         if (type >= nr_swapfiles)
 124                 goto bad_nofile;
 125         p = & swap_info[type];
 126         if (!(p->flags & SWP_USED))
 127                 goto bad_device;
 128         if (p->prio > swap_info[swap_list.next].prio)
 129                 swap_list.next = swap_list.head;
 130         offset = SWP_OFFSET(entry);
 131         if (offset >= p->max)
 132                 goto bad_offset;
 133         if (offset < p->lowest_bit)
 134                 p->lowest_bit = offset;
 135         if (offset > p->highest_bit)
 136                 p->highest_bit = offset;
 137         if (!p->swap_map[offset])
 138                 goto bad_free;
 139         if (p->swap_map[offset] < SWAP_MAP_MAX) {
 140                 if (!--p->swap_map[offset])
 141                         nr_swap_pages++;
 142         }
 143 #ifdef DEBUG_SWAP
 144         printk("DebugVM: swap_free(entry %08lx, count now %d)\n",
 145                entry, p->swap_map[offset]);
 146 #endif
 147 out:
 148         return;
 149
 150 bad_nofile:
 151         printk("swap_free: Trying to free nonexistent swap-page\n");
 152         goto out;
 153 bad_device:
 154         printk("swap_free: Trying to free swap from unused swap-device\n");
 155         goto out;
 156 bad_offset:
 157         printk("swap_free: offset exceeds max\n");
 158         goto out;
 159 bad_free:
 160         printk("swap_free: swap-space map bad (entry %08lx)\n",entry);
 161         goto out;
 162 }
 163
 164 /*
 165  * The swap entry has been read in advance, and we return 1 to indicate
 166  * that the page has been used or is no longer needed.
 167  *
 168  * Always set the resulting pte to be nowrite (the same as COW pages
 169  * after one process has exited).  We don't know just how many PTEs will
 170  * share this swap entry, so be cautious and let do_wp_page work out
 171  * what to do if a write is requested later.
 172  */
 173 static inline void unuse_pte(struct vm_area_struct * vma, unsigned long address,
 174         pte_t *dir, unsigned long entry, unsigned long page)
 175 {
 176         pte_t pte = *dir;
 177
 178         if (pte_none(pte))
 179                 return;
 180         if (pte_present(pte)) {
 181                 /* If this entry is swap-cached, then page must already
 182                    hold the right address for any copies in physical
 183                    memory */
 184                 if (pte_page(pte) != page)
 185                         return;
 186                 /* We will be removing the swap cache in a moment, so... */
 187                 set_pte(dir, pte_mkdirty(pte));
 188                 return;
 189         }
 190         if (pte_val(pte) != entry)
 191                 return;
 192         set_pte(dir, pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
 193         swap_free(entry);
 194         atomic_inc(&mem_map[MAP_NR(page)].count);
 195         ++vma->vm_mm->rss;
 196 }
 197
 198 static inline void unuse_pmd(struct vm_area_struct * vma, pmd_t *dir,
 199         unsigned long address, unsigned long size, unsigned long offset,
 200         unsigned long entry, unsigned long page)
 201 {
 202         pte_t * pte;
 203         unsigned long end;
 204
 205         if (pmd_none(*dir))
 206                 return;
 207         if (pmd_bad(*dir)) {
 208                 printk("unuse_pmd: bad pmd (%08lx)\n", pmd_val(*dir));
 209                 pmd_clear(dir);
 210                 return;
 211         }
 212         pte = pte_offset(dir, address);
 213         offset += address & PMD_MASK;
 214         address &= ~PMD_MASK;
 215         end = address + size;
 216         if (end > PMD_SIZE)
 217                 end = PMD_SIZE;
 218         do {
 219                 unuse_pte(vma, offset+address-vma->vm_start, pte, entry, page);
 220                 address += PAGE_SIZE;
 221                 pte++;
 222         } while (address < end);
 223 }
 224
 225 static inline void unuse_pgd(struct vm_area_struct * vma, pgd_t *dir,
 226         unsigned long address, unsigned long size,
 227         unsigned long entry, unsigned long page)
 228 {
 229         pmd_t * pmd;
 230         unsigned long offset, end;
 231
 232         if (pgd_none(*dir))
 233                 return;
 234         if (pgd_bad(*dir)) {
 235                 printk("unuse_pgd: bad pgd (%08lx)\n", pgd_val(*dir));
 236                 pgd_clear(dir);
 237                 return;
 238         }
 239         pmd = pmd_offset(dir, address);
 240         offset = address & PGDIR_MASK;
 241         address &= ~PGDIR_MASK;
 242         end = address + size;
 243         if (end > PGDIR_SIZE)
 244                 end = PGDIR_SIZE;
 245         do {
 246                 unuse_pmd(vma, pmd, address, end - address, offset, entry,
 247                           page);
 248                 address = (address + PMD_SIZE) & PMD_MASK;
 249                 pmd++;
 250         } while (address < end);
 251 }
 252
 253 static void unuse_vma(struct vm_area_struct * vma, pgd_t *pgdir,
 254                         unsigned long entry, unsigned long page)
 255 {
 256         unsigned long start = vma->vm_start, end = vma->vm_end;
 257
 258         while (start < end) {
 259                 unuse_pgd(vma, pgdir, start, end - start, entry, page);
 260                 start = (start + PGDIR_SIZE) & PGDIR_MASK;
 261                 pgdir++;
 262         }
 263 }
 264
 265 static void unuse_process(struct mm_struct * mm, unsigned long entry,
 266                         unsigned long page)
 267 {
 268         struct vm_area_struct* vma;
 269
 270         /*
 271          * Go through process' page directory.
 272          */
 273         if (!mm || mm == &init_mm)
 274                 return;
 275         for (vma = mm->mmap; vma; vma = vma->vm_next) {
 276                 pgd_t * pgd = pgd_offset(mm, vma->vm_start);
 277                 unuse_vma(vma, pgd, entry, page);
 278         }
 279         return;
 280 }
 281
 282 /*
 283  * We completely avoid races by reading each swap page in advance,
 284  * and then search for the process using it.  All the necessary
 285  * page table adjustments can then be made atomically.
 286  */
 287 static int try_to_unuse(unsigned int type)
 288 {
 289         struct swap_info_struct * si = &swap_info[type];
 290         struct task_struct *p;
 291         struct page *page_map;
 292         unsigned long entry, page;
 293         int i;
 294
 295         while (1) {
 296                 /*
 297                  * Find a swap page in use and read it in.
 298                  */
 299                 for (i = 1; i < si->max ; i++) {
 300                         if (si->swap_map[i] > 0 && si->swap_map[i] != SWAP_MAP_BAD) {
 301                                 goto found_entry;
 302                         }
 303                 }
 304                 break;
 305
 306         found_entry:
 307                 entry = SWP_ENTRY(type, i);
 308
 309                 /* Get a page for the entry, using the existing swap
 310                    cache page if there is one.  Otherwise, get a clean
 311                    page and read the swap into it. */
 312                 page_map = read_swap_cache(entry);
 313                 if (!page_map) {
 314                         /*
 315                          * Continue searching if the entry became unused.
 316                          */
 317                         if (si->swap_map[i] == 0)
 318                                 continue;
 319                         return -ENOMEM;
 320                 }
 321                 page = page_address(page_map);
 322                 read_lock(&tasklist_lock);
 323                 for_each_task(p)
 324                         unuse_process(p->mm, entry, page);
 325                 read_unlock(&tasklist_lock);
 326                 shm_unuse(entry, page);
 327                 /* Now get rid of the extra reference to the temporary
 328                    page we've been using. */
 329                 if (PageSwapCache(page_map))
 330                         delete_from_swap_cache(page_map);
 331                 __free_page(page_map);
 332                 /*
 333                  * Check for and clear any overflowed swap map counts.
 334                  */
 335                 if (si->swap_map[i] != 0) {
 336                         if (si->swap_map[i] != SWAP_MAP_MAX)
 337                                 printk(KERN_ERR
 338                                         "try_to_unuse: entry %08lx count=%d\n",
 339                                         entry, si->swap_map[i]);
 340                         si->swap_map[i] = 0;
 341                         nr_swap_pages++;
 342                 }
 343         }
 344         return 0;
 345 }
 346
 347 asmlinkage int sys_swapoff(const char * specialfile)
 348 {
 349         struct swap_info_struct * p = NULL;
 350         struct dentry * dentry;
 351         struct file filp;
 352         int i, type, prev;
 353         int err = -EPERM;
 354
 355         lock_kernel();
 356         if (!capable(CAP_SYS_ADMIN))
 357                 goto out;
 358
 359         dentry = namei(specialfile);
 360         err = PTR_ERR(dentry);
 361         if (IS_ERR(dentry))
 362                 goto out;
 363
 364         prev = -1;
 365         for (type = swap_list.head; type >= 0; type = swap_info[type].next) {
 366                 p = swap_info + type;
 367                 if ((p->flags & SWP_WRITEOK) == SWP_WRITEOK) {
 368                         if (p->swap_file) {
 369                                 if (p->swap_file == dentry)
 370                                   break;
 371                         } else {
 372                                 if (S_ISBLK(dentry->d_inode->i_mode)
 373                                     && (p->swap_device == dentry->d_inode->i_rdev))
 374                                   break;
 375                         }
 376                 }
 377                 prev = type;
 378         }
 379         err = -EINVAL;
 380         if (type < 0)
 381                 goto out_dput;
 382
 383         if (prev < 0) {
 384                 swap_list.head = p->next;
 385         } else {
 386                 swap_info[prev].next = p->next;
 387         }
 388         if (type == swap_list.next) {
 389                 /* just pick something that's safe... */
 390                 swap_list.next = swap_list.head;
 391         }
 392         p->flags = SWP_USED;
 393         err = try_to_unuse(type);
 394         if (err) {
 395                 /* re-insert swap space back into swap_list */
 396                 for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next)
 397                         if (p->prio >= swap_info[i].prio)
 398                                 break;
 399                 p->next = i;
 400                 if (prev < 0)
 401                         swap_list.head = swap_list.next = p - swap_info;
 402                 else
 403                         swap_info[prev].next = p - swap_info;
 404                 p->flags = SWP_WRITEOK;
 405                 goto out_dput;
 406         }
 407         if(p->swap_device){
 408                 memset(&filp, 0, sizeof(filp));
 409                 filp.f_dentry = dentry;
 410                 filp.f_mode = 3; /* read write */
 411                 /* open it again to get fops */
 412                 if( !blkdev_open(dentry->d_inode, &filp) &&
 413                    filp.f_op && filp.f_op->release){
 414                         filp.f_op->release(dentry->d_inode,&filp);
 415                         filp.f_op->release(dentry->d_inode,&filp);
 416                 }
 417         }
 418         dput(dentry);
 419
 420         dentry = p->swap_file;
 421         p->swap_file = NULL;
 422         nr_swap_pages -= p->pages;
 423         p->swap_device = 0;
 424         vfree(p->swap_map);
 425         p->swap_map = NULL;
 426         vfree(p->swap_lockmap);
 427         p->swap_lockmap = NULL;
 428         p->flags = 0;
 429         err = 0;
 430
 431 out_dput:
 432         dput(dentry);
 433 out:
 434         unlock_kernel();
 435         return err;
 436 }
 437
 438 int get_swaparea_info(char *buf)
 439 {
 440         char * page = (char *) __get_free_page(GFP_KERNEL);
 441         struct swap_info_struct *ptr = swap_info;
 442         int i, j, len = 0, usedswap;
 443
 444         if (!page)
 445                 return -ENOMEM;
 446
 447         len += sprintf(buf, "Filename\t\t\tType\t\tSize\tUsed\tPriority\n");
 448         for (i = 0 ; i < nr_swapfiles ; i++, ptr++) {
 449                 if (ptr->flags & SWP_USED) {
 450                         char * path = d_path(ptr->swap_file, page, PAGE_SIZE);
 451
 452                         len += sprintf(buf + len, "%-31s ", path);
 453
 454                         if (!ptr->swap_device)
 455                                 len += sprintf(buf + len, "file\t\t");
 456                         else
 457                                 len += sprintf(buf + len, "partition\t");
 458
 459                         usedswap = 0;
 460                         for (j = 0; j < ptr->max; ++j)
 461                                 switch (ptr->swap_map[j]) {
 462                                         case SWAP_MAP_BAD:
 463                                         case 0:
 464                                                 continue;
 465                                         default:
 466                                                 usedswap++;
 467                                 }
 468                         len += sprintf(buf + len, "%d\t%d\t%d\n", ptr->pages << (PAGE_SHIFT - 10),
 469                                 usedswap << (PAGE_SHIFT - 10), ptr->prio);
 470                 }
 471         }
 472         free_page((unsigned long) page);
 473         return len;
 474 }
 475
 476 /*
 477  * Written 01/25/92 by Simmule Turner, heavily changed by Linus.
 478  *
 479  * The swapon system call
 480  */
 481 asmlinkage int sys_swapon(const char * specialfile, int swap_flags)
 482 {
 483         struct swap_info_struct * p;
 484         struct dentry * swap_dentry;
 485         unsigned int type;
 486         int i, j, prev;
 487         int error = -EPERM;
 488         struct file filp;
 489         static int least_priority = 0;
 490         union swap_header *swap_header = 0;
 491         int swap_header_version;
 492         int lock_map_size = PAGE_SIZE;
 493         int nr_good_pages = 0;
 494         unsigned long tmp_lock_map = 0;
 495
 496         lock_kernel();
 497         if (!capable(CAP_SYS_ADMIN))
 498                 goto out;
 499         memset(&filp, 0, sizeof(filp));
 500         p = swap_info;
 501         for (type = 0 ; type < nr_swapfiles ; type++,p++)
 502                 if (!(p->flags & SWP_USED))
 503                         break;
 504         if (type >= MAX_SWAPFILES)
 505                 goto out;
 506         if (type >= nr_swapfiles)
 507                 nr_swapfiles = type+1;
 508         p->flags = SWP_USED;
 509         p->swap_file = NULL;
 510         p->swap_device = 0;
 511         p->swap_map = NULL;
 512         p->swap_lockmap = NULL;
 513         p->lowest_bit = 0;
 514         p->highest_bit = 0;
 515         p->cluster_nr = 0;
 516         p->max = 1;
 517         p->next = -1;
 518         if (swap_flags & SWAP_FLAG_PREFER) {
 519                 p->prio =
 520                   (swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT;
 521         } else {
 522                 p->prio = --least_priority;
 523         }
 524         swap_dentry = namei(specialfile);
 525         error = PTR_ERR(swap_dentry);
 526         if (IS_ERR(swap_dentry))
 527                 goto bad_swap_2;
 528
 529         p->swap_file = swap_dentry;
 530         error = -EINVAL;
 531
 532         if (S_ISBLK(swap_dentry->d_inode->i_mode)) {
 533                 p->swap_device = swap_dentry->d_inode->i_rdev;
 534                 set_blocksize(p->swap_device, PAGE_SIZE);
 535
 536                 filp.f_dentry = swap_dentry;
 537                 filp.f_mode = 3; /* read write */
 538                 error = blkdev_open(swap_dentry->d_inode, &filp);
 539                 if (error)
 540                         goto bad_swap_2;
 541                 set_blocksize(p->swap_device, PAGE_SIZE);
 542                 error = -ENODEV;
 543                 if (!p->swap_device ||
 544                     (blk_size[MAJOR(p->swap_device)] &&
 545                      !blk_size[MAJOR(p->swap_device)][MINOR(p->swap_device)]))
 546                         goto bad_swap;
 547                 error = -EBUSY;
 548                 for (i = 0 ; i < nr_swapfiles ; i++) {
 549                         if (i == type)
 550                                 continue;
 551                         if (p->swap_device == swap_info[i].swap_device)
 552                                 goto bad_swap;
 553                 }
 554         } else if (S_ISREG(swap_dentry->d_inode->i_mode)) {
 555                 error = -EBUSY;
 556                 for (i = 0 ; i < nr_swapfiles ; i++) {
 557                         if (i == type)
 558                                 continue;
 559                         if (swap_dentry->d_inode == swap_info[i].swap_file->d_inode)
 560                                 goto bad_swap;
 561                 }
 562         } else
 563                 goto bad_swap;
 564
 565         swap_header = (void *) __get_free_page(GFP_USER);
 566         if (!swap_header) {
 567                 printk("Unable to start swapping: out of memory :-)\n");
 568                 error = -ENOMEM;
 569                 goto bad_swap;
 570         }
 571
 572         p->swap_lockmap = (char *) &tmp_lock_map;
 573         rw_swap_page_nocache(READ, SWP_ENTRY(type,0), (char *) swap_header);
 574         p->swap_lockmap = NULL;
 575
 576         if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10))
 577                 swap_header_version = 1;
 578         else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10))
 579                 swap_header_version = 2;
 580         else {
 581                 printk("Unable to find swap-space signature\n");
 582                 error = -EINVAL;
 583                 goto bad_swap;
 584         }
 585
 586         switch (swap_header_version) {
 587         case 1:
 588                 memset(((char *) swap_header)+PAGE_SIZE-10,0,10);
 589                 j = 0;
 590                 p->lowest_bit = 0;
 591                 p->highest_bit = 0;
 592                 for (i = 1 ; i < 8*PAGE_SIZE ; i++) {
 593                         if (test_bit(i,(char *) swap_header)) {
 594                                 if (!p->lowest_bit)
 595                                         p->lowest_bit = i;
 596                                 p->highest_bit = i;
 597                                 p->max = i+1;
 598                                 j++;
 599                         }
 600                 }
 601                 nr_good_pages = j;
 602                 p->swap_map = vmalloc(p->max * sizeof(short));
 603                 if (!p->swap_map) {
 604                         error = -ENOMEM;
 605                         goto bad_swap;
 606                 }
 607                 for (i = 1 ; i < p->max ; i++) {
 608                         if (test_bit(i,(char *) swap_header))
 609                                 p->swap_map[i] = 0;
 610                         else
 611                                 p->swap_map[i] = SWAP_MAP_BAD;
 612                 }
 613                 break;
 614
 615         case 2:
 616                 /* Check the swap header's sub-version and the size of
 617                    the swap file and bad block lists */
 618                 if (swap_header->info.version != 1) {
 619                         printk(KERN_WARNING
 620                                "Unable to handle swap header version %d\n",
 621                                swap_header->info.version);
 622                         error = -EINVAL;
 623                         goto bad_swap;
 624                 }
 625
 626                 p->lowest_bit  = 1;
 627                 p->highest_bit = swap_header->info.last_page - 1;
 628                 p->max         = swap_header->info.last_page;
 629
 630                 error = -EINVAL;
 631                 if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
 632                         goto bad_swap;
 633                 if (p->max >= SWP_OFFSET(SWP_ENTRY(0,~0UL)))
 634                         goto bad_swap;
 635
 636                 /* OK, set up the swap map and apply the bad block list */
 637                 if (!(p->swap_map = vmalloc (p->max * sizeof(short)))) {
 638                         error = -ENOMEM;
 639                         goto bad_swap;
 640                 }
 641
 642                 error = 0;
 643                 memset(p->swap_map, 0, p->max * sizeof(short));
 644                 for (i=0; i<swap_header->info.nr_badpages; i++) {
 645                         int page = swap_header->info.badpages[i];
 646                         if (page <= 0 || page >= swap_header->info.last_page)
 647                                 error = -EINVAL;
 648                         else
 649                                 p->swap_map[page] = SWAP_MAP_BAD;
 650                 }
 651                 nr_good_pages = swap_header->info.last_page - i;
 652                 lock_map_size = (p->max + 7) / 8;
 653                 if (error)
 654                         goto bad_swap;
 655         }
 656
 657         if (!nr_good_pages) {
 658                 printk(KERN_WARNING "Empty swap-file\n");
 659                 error = -EINVAL;
 660                 goto bad_swap;
 661         }
 662         p->swap_map[0] = SWAP_MAP_BAD;
 663         if (!(p->swap_lockmap = vmalloc (lock_map_size))) {
 664                 error = -ENOMEM;
 665                 goto bad_swap;
 666         }
 667         memset(p->swap_lockmap,0,lock_map_size);
 668         p->flags = SWP_WRITEOK;
 669         p->pages = nr_good_pages;
 670         nr_swap_pages += nr_good_pages;
 671         printk(KERN_INFO "Adding Swap: %dk swap-space (priority %d)\n",
 672                nr_good_pages<<(PAGE_SHIFT-10), p->prio);
 673
 674         /* insert swap space into swap_list: */
 675         prev = -1;
 676         for (i = swap_list.head; i >= 0; i = swap_info[i].next) {
 677                 if (p->prio >= swap_info[i].prio) {
 678                         break;
 679                 }
 680                 prev = i;
 681         }
 682         p->next = i;
 683         if (prev < 0) {
 684                 swap_list.head = swap_list.next = p - swap_info;
 685         } else {
 686                 swap_info[prev].next = p - swap_info;
 687         }
 688         error = 0;
 689         goto out;
 690 bad_swap:
 691         if(filp.f_op && filp.f_op->release)
 692                 filp.f_op->release(filp.f_dentry->d_inode,&filp);
 693 bad_swap_2:
 694         if (p->swap_lockmap)
 695                 vfree(p->swap_lockmap);
 696         if (p->swap_map)
 697                 vfree(p->swap_map);
 698         dput(p->swap_file);
 699         p->swap_device = 0;
 700         p->swap_file = NULL;
 701         p->swap_map = NULL;
 702         p->swap_lockmap = NULL;
 703         p->flags = 0;
 704         if (!(swap_flags & SWAP_FLAG_PREFER))
 705                 ++least_priority;
 706 out:
 707         if (swap_header)
 708                 free_page((long) swap_header);
 709         unlock_kernel();
 710         return error;
 711 }
 712
 713 void si_swapinfo(struct sysinfo *val)
 714 {
 715         unsigned int i, j;
 716
 717         val->freeswap = val->totalswap = 0;
 718         for (i = 0; i < nr_swapfiles; i++) {
 719                 if ((swap_info[i].flags & SWP_WRITEOK) != SWP_WRITEOK)
 720                         continue;
 721                 for (j = 0; j < swap_info[i].max; ++j)
 722                         switch (swap_info[i].swap_map[j]) {
 723                                 case SWAP_MAP_BAD:
 724                                         continue;
 725                                 case 0:
 726                                         ++val->freeswap;
 727                                 default:
 728                                         ++val->totalswap;
 729                         }
 730         }
 731         val->freeswap <<= PAGE_SHIFT;
 732         val->totalswap <<= PAGE_SHIFT;
 733         return;
 734 }