kernel/lockdep_proc.c

   1 /*
   2  * kernel/lockdep_proc.c
   3  *
   4  * Runtime locking correctness validator
   5  *
   6  * Started by Ingo Molnar:
   7  *
   8  *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   9  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
  10  *
  11  * Code for /proc/lockdep and /proc/lockdep_stats:
  12  *
  13  */
  14 #include <linux/module.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/kallsyms.h>
  18 #include <linux/debug_locks.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/sort.h>
  21 #include <asm/uaccess.h>
  22 #include <asm/div64.h>
  23
  24 #include "lockdep_internals.h"
  25
  26 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
  27 {
  28         struct lock_class *class;
  29
  30         (*pos)++;
  31
  32         if (v == SEQ_START_TOKEN)
  33                 class = m->private;
  34         else {
  35                 class = v;
  36
  37                 if (class->lock_entry.next != &all_lock_classes)
  38                         class = list_entry(class->lock_entry.next,
  39                                            struct lock_class, lock_entry);
  40                 else
  41                         class = NULL;
  42         }
  43
  44         return class;
  45 }
  46
  47 static void *l_start(struct seq_file *m, loff_t *pos)
  48 {
  49         struct lock_class *class;
  50         loff_t i = 0;
  51
  52         if (*pos == 0)
  53                 return SEQ_START_TOKEN;
  54
  55         list_for_each_entry(class, &all_lock_classes, lock_entry) {
  56                 if (++i == *pos)
  57                 return class;
  58         }
  59         return NULL;
  60 }
  61
  62 static void l_stop(struct seq_file *m, void *v)
  63 {
  64 }
  65
  66 static unsigned long count_forward_deps(struct lock_class *class)
  67 {
  68         struct lock_list *entry;
  69         unsigned long ret = 1;
  70
  71         /*
  72          * Recurse this class's dependency list:
  73          */
  74         list_for_each_entry(entry, &class->locks_after, entry)
  75                 ret += count_forward_deps(entry->class);
  76
  77         return ret;
  78 }
  79
  80 static unsigned long count_backward_deps(struct lock_class *class)
  81 {
  82         struct lock_list *entry;
  83         unsigned long ret = 1;
  84
  85         /*
  86          * Recurse this class's dependency list:
  87          */
  88         list_for_each_entry(entry, &class->locks_before, entry)
  89                 ret += count_backward_deps(entry->class);
  90
  91         return ret;
  92 }
  93
  94 static void print_name(struct seq_file *m, struct lock_class *class)
  95 {
  96         char str[128];
  97         const char *name = class->name;
  98
  99         if (!name) {
 100                 name = __get_key_name(class->key, str);
 101                 seq_printf(m, "%s", name);
 102         } else{
 103                 seq_printf(m, "%s", name);
 104                 if (class->name_version > 1)
 105                         seq_printf(m, "#%d", class->name_version);
 106                 if (class->subclass)
 107                         seq_printf(m, "/%d", class->subclass);
 108         }
 109 }
 110
 111 static int l_show(struct seq_file *m, void *v)
 112 {
 113         unsigned long nr_forward_deps, nr_backward_deps;
 114         struct lock_class *class = v;
 115         struct lock_list *entry;
 116         char c1, c2, c3, c4;
 117
 118         if (v == SEQ_START_TOKEN) {
 119                 seq_printf(m, "all lock classes:\n");
 120                 return 0;
 121         }
 122
 123         seq_printf(m, "%p", class->key);
 124 #ifdef CONFIG_DEBUG_LOCKDEP
 125         seq_printf(m, " OPS:%8ld", class->ops);
 126 #endif
 127         nr_forward_deps = count_forward_deps(class);
 128         seq_printf(m, " FD:%5ld", nr_forward_deps);
 129
 130         nr_backward_deps = count_backward_deps(class);
 131         seq_printf(m, " BD:%5ld", nr_backward_deps);
 132
 133         get_usage_chars(class, &c1, &c2, &c3, &c4);
 134         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
 135
 136         seq_printf(m, ": ");
 137         print_name(m, class);
 138         seq_puts(m, "\n");
 139
 140         list_for_each_entry(entry, &class->locks_after, entry) {
 141                 if (entry->distance == 1) {
 142                         seq_printf(m, " -> [%p] ", entry->class->key);
 143                         print_name(m, entry->class);
 144                         seq_puts(m, "\n");
 145                 }
 146         }
 147         seq_puts(m, "\n");
 148
 149         return 0;
 150 }
 151
 152 static const struct seq_operations lockdep_ops = {
 153         .start  = l_start,
 154         .next   = l_next,
 155         .stop   = l_stop,
 156         .show   = l_show,
 157 };
 158
 159 static int lockdep_open(struct inode *inode, struct file *file)
 160 {
 161         int res = seq_open(file, &lockdep_ops);
 162         if (!res) {
 163                 struct seq_file *m = file->private_data;
 164
 165                 if (!list_empty(&all_lock_classes))
 166                         m->private = list_entry(all_lock_classes.next,
 167                                         struct lock_class, lock_entry);
 168                 else
 169                         m->private = NULL;
 170         }
 171         return res;
 172 }
 173
 174 static const struct file_operations proc_lockdep_operations = {
 175         .open           = lockdep_open,
 176         .read           = seq_read,
 177         .llseek         = seq_lseek,
 178         .release        = seq_release,
 179 };
 180
 181 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
 182 {
 183         struct lock_chain *chain;
 184
 185         (*pos)++;
 186
 187         if (v == SEQ_START_TOKEN)
 188                 chain = m->private;
 189         else {
 190                 chain = v;
 191
 192                 if (*pos < nr_lock_chains)
 193                         chain = lock_chains + *pos;
 194                 else
 195                         chain = NULL;
 196         }
 197
 198         return chain;
 199 }
 200
 201 static void *lc_start(struct seq_file *m, loff_t *pos)
 202 {
 203         if (*pos == 0)
 204                 return SEQ_START_TOKEN;
 205
 206         if (*pos < nr_lock_chains)
 207                 return lock_chains + *pos;
 208
 209         return NULL;
 210 }
 211
 212 static void lc_stop(struct seq_file *m, void *v)
 213 {
 214 }
 215
 216 static int lc_show(struct seq_file *m, void *v)
 217 {
 218         struct lock_chain *chain = v;
 219         struct lock_class *class;
 220         int i;
 221
 222         if (v == SEQ_START_TOKEN) {
 223                 seq_printf(m, "all lock chains:\n");
 224                 return 0;
 225         }
 226
 227         seq_printf(m, "irq_context: %d\n", chain->irq_context);
 228
 229         for (i = 0; i < chain->depth; i++) {
 230                 class = lock_chain_get_class(chain, i);
 231                 seq_printf(m, "[%p] ", class->key);
 232                 print_name(m, class);
 233                 seq_puts(m, "\n");
 234         }
 235         seq_puts(m, "\n");
 236
 237         return 0;
 238 }
 239
 240 static const struct seq_operations lockdep_chains_ops = {
 241         .start  = lc_start,
 242         .next   = lc_next,
 243         .stop   = lc_stop,
 244         .show   = lc_show,
 245 };
 246
 247 static int lockdep_chains_open(struct inode *inode, struct file *file)
 248 {
 249         int res = seq_open(file, &lockdep_chains_ops);
 250         if (!res) {
 251                 struct seq_file *m = file->private_data;
 252
 253                 if (nr_lock_chains)
 254                         m->private = lock_chains;
 255                 else
 256                         m->private = NULL;
 257         }
 258         return res;
 259 }
 260
 261 static const struct file_operations proc_lockdep_chains_operations = {
 262         .open           = lockdep_chains_open,
 263         .read           = seq_read,
 264         .llseek         = seq_lseek,
 265         .release        = seq_release,
 266 };
 267
 268 static void lockdep_stats_debug_show(struct seq_file *m)
 269 {
 270 #ifdef CONFIG_DEBUG_LOCKDEP
 271         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 272                      hi2 = debug_atomic_read(&hardirqs_off_events),
 273                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 274                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 275                      si1 = debug_atomic_read(&softirqs_on_events),
 276                      si2 = debug_atomic_read(&softirqs_off_events),
 277                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 278                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 279
 280         seq_printf(m, " chain lookup misses:           %11u\n",
 281                 debug_atomic_read(&chain_lookup_misses));
 282         seq_printf(m, " chain lookup hits:             %11u\n",
 283                 debug_atomic_read(&chain_lookup_hits));
 284         seq_printf(m, " cyclic checks:                 %11u\n",
 285                 debug_atomic_read(&nr_cyclic_checks));
 286         seq_printf(m, " cyclic-check recursions:       %11u\n",
 287                 debug_atomic_read(&nr_cyclic_check_recursions));
 288         seq_printf(m, " find-mask forwards checks:     %11u\n",
 289                 debug_atomic_read(&nr_find_usage_forwards_checks));
 290         seq_printf(m, " find-mask forwards recursions: %11u\n",
 291                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 292         seq_printf(m, " find-mask backwards checks:    %11u\n",
 293                 debug_atomic_read(&nr_find_usage_backwards_checks));
 294         seq_printf(m, " find-mask backwards recursions:%11u\n",
 295                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 296
 297         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 298         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 299         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 300         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 301         seq_printf(m, " softirq on events:             %11u\n", si1);
 302         seq_printf(m, " softirq off events:            %11u\n", si2);
 303         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 304         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 305 #endif
 306 }
 307
 308 static int lockdep_stats_show(struct seq_file *m, void *v)
 309 {
 310         struct lock_class *class;
 311         unsigned long nr_unused = 0, nr_uncategorized = 0,
 312                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 313                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 314                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 315                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 316                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 317                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 318                       sum_forward_deps = 0, factor = 0;
 319
 320         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 321
 322                 if (class->usage_mask == 0)
 323                         nr_unused++;
 324                 if (class->usage_mask == LOCKF_USED)
 325                         nr_uncategorized++;
 326                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 327                         nr_irq_safe++;
 328                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
 329                         nr_irq_unsafe++;
 330                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 331                         nr_softirq_safe++;
 332                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
 333                         nr_softirq_unsafe++;
 334                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 335                         nr_hardirq_safe++;
 336                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
 337                         nr_hardirq_unsafe++;
 338                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 339                         nr_irq_read_safe++;
 340                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
 341                         nr_irq_read_unsafe++;
 342                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 343                         nr_softirq_read_safe++;
 344                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
 345                         nr_softirq_read_unsafe++;
 346                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 347                         nr_hardirq_read_safe++;
 348                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
 349                         nr_hardirq_read_unsafe++;
 350
 351                 sum_forward_deps += count_forward_deps(class);
 352         }
 353 #ifdef CONFIG_DEBUG_LOCKDEP
 354         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 355 #endif
 356         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 357                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 358         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 359                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 360         seq_printf(m, " indirect dependencies:         %11lu\n",
 361                         sum_forward_deps);
 362
 363         /*
 364          * Total number of dependencies:
 365          *
 366          * All irq-safe locks may nest inside irq-unsafe locks,
 367          * plus all the other known dependencies:
 368          */
 369         seq_printf(m, " all direct dependencies:       %11lu\n",
 370                         nr_irq_unsafe * nr_irq_safe +
 371                         nr_hardirq_unsafe * nr_hardirq_safe +
 372                         nr_list_entries);
 373
 374         /*
 375          * Estimated factor between direct and indirect
 376          * dependencies:
 377          */
 378         if (nr_list_entries)
 379                 factor = sum_forward_deps / nr_list_entries;
 380
 381 #ifdef CONFIG_PROVE_LOCKING
 382         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 383                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 384         seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
 385                         atomic_read(&nr_chain_hlocks), MAX_LOCKDEP_CHAIN_HLOCKS);
 386 #endif
 387
 388 #ifdef CONFIG_TRACE_IRQFLAGS
 389         seq_printf(m, " in-hardirq chains:             %11u\n",
 390                         nr_hardirq_chains);
 391         seq_printf(m, " in-softirq chains:             %11u\n",
 392                         nr_softirq_chains);
 393 #endif
 394         seq_printf(m, " in-process chains:             %11u\n",
 395                         nr_process_chains);
 396         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 397                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 398         seq_printf(m, " combined max dependencies:     %11u\n",
 399                         (nr_hardirq_chains + 1) *
 400                         (nr_softirq_chains + 1) *
 401                         (nr_process_chains + 1)
 402         );
 403         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 404                         nr_hardirq_safe);
 405         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 406                         nr_hardirq_unsafe);
 407         seq_printf(m, " softirq-safe locks:            %11lu\n",
 408                         nr_softirq_safe);
 409         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 410                         nr_softirq_unsafe);
 411         seq_printf(m, " irq-safe locks:                %11lu\n",
 412                         nr_irq_safe);
 413         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 414                         nr_irq_unsafe);
 415
 416         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 417                         nr_hardirq_read_safe);
 418         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 419                         nr_hardirq_read_unsafe);
 420         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 421                         nr_softirq_read_safe);
 422         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 423                         nr_softirq_read_unsafe);
 424         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 425                         nr_irq_read_safe);
 426         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 427                         nr_irq_read_unsafe);
 428
 429         seq_printf(m, " uncategorized locks:           %11lu\n",
 430                         nr_uncategorized);
 431         seq_printf(m, " unused locks:                  %11lu\n",
 432                         nr_unused);
 433         seq_printf(m, " max locking depth:             %11u\n",
 434                         max_lockdep_depth);
 435         seq_printf(m, " max recursion depth:           %11u\n",
 436                         max_recursion_depth);
 437         lockdep_stats_debug_show(m);
 438         seq_printf(m, " debug_locks:                   %11u\n",
 439                         debug_locks);
 440
 441         return 0;
 442 }
 443
 444 static int lockdep_stats_open(struct inode *inode, struct file *file)
 445 {
 446         return single_open(file, lockdep_stats_show, NULL);
 447 }
 448
 449 static const struct file_operations proc_lockdep_stats_operations = {
 450         .open           = lockdep_stats_open,
 451         .read           = seq_read,
 452         .llseek         = seq_lseek,
 453         .release        = single_release,
 454 };
 455
 456 #ifdef CONFIG_LOCK_STAT
 457
 458 struct lock_stat_data {
 459         struct lock_class *class;
 460         struct lock_class_stats stats;
 461 };
 462
 463 struct lock_stat_seq {
 464         struct lock_stat_data *iter;
 465         struct lock_stat_data *iter_end;
 466         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 467 };
 468
 469 /*
 470  * sort on absolute number of contentions
 471  */
 472 static int lock_stat_cmp(const void *l, const void *r)
 473 {
 474         const struct lock_stat_data *dl = l, *dr = r;
 475         unsigned long nl, nr;
 476
 477         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 478         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 479
 480         return nr - nl;
 481 }
 482
 483 static void seq_line(struct seq_file *m, char c, int offset, int length)
 484 {
 485         int i;
 486
 487         for (i = 0; i < offset; i++)
 488                 seq_puts(m, " ");
 489         for (i = 0; i < length; i++)
 490                 seq_printf(m, "%c", c);
 491         seq_puts(m, "\n");
 492 }
 493
 494 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 495 {
 496         unsigned long rem;
 497
 498         rem = do_div(nr, 1000); /* XXX: do_div_signed */
 499         snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
 500 }
 501
 502 static void seq_time(struct seq_file *m, s64 time)
 503 {
 504         char num[15];
 505
 506         snprint_time(num, sizeof(num), time);
 507         seq_printf(m, " %14s", num);
 508 }
 509
 510 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 511 {
 512         seq_printf(m, "%14lu", lt->nr);
 513         seq_time(m, lt->min);
 514         seq_time(m, lt->max);
 515         seq_time(m, lt->total);
 516 }
 517
 518 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 519 {
 520         char name[39];
 521         struct lock_class *class;
 522         struct lock_class_stats *stats;
 523         int i, namelen;
 524
 525         class = data->class;
 526         stats = &data->stats;
 527
 528         namelen = 38;
 529         if (class->name_version > 1)
 530                 namelen -= 2; /* XXX truncates versions > 9 */
 531         if (class->subclass)
 532                 namelen -= 2;
 533
 534         if (!class->name) {
 535                 char str[KSYM_NAME_LEN];
 536                 const char *key_name;
 537
 538                 key_name = __get_key_name(class->key, str);
 539                 snprintf(name, namelen, "%s", key_name);
 540         } else {
 541                 snprintf(name, namelen, "%s", class->name);
 542         }
 543         namelen = strlen(name);
 544         if (class->name_version > 1) {
 545                 snprintf(name+namelen, 3, "#%d", class->name_version);
 546                 namelen += 2;
 547         }
 548         if (class->subclass) {
 549                 snprintf(name+namelen, 3, "/%d", class->subclass);
 550                 namelen += 2;
 551         }
 552
 553         if (stats->write_holdtime.nr) {
 554                 if (stats->read_holdtime.nr)
 555                         seq_printf(m, "%38s-W:", name);
 556                 else
 557                         seq_printf(m, "%40s:", name);
 558
 559                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
 560                 seq_lock_time(m, &stats->write_waittime);
 561                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
 562                 seq_lock_time(m, &stats->write_holdtime);
 563                 seq_puts(m, "\n");
 564         }
 565
 566         if (stats->read_holdtime.nr) {
 567                 seq_printf(m, "%38s-R:", name);
 568                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
 569                 seq_lock_time(m, &stats->read_waittime);
 570                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
 571                 seq_lock_time(m, &stats->read_holdtime);
 572                 seq_puts(m, "\n");
 573         }
 574
 575         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 576                 return;
 577
 578         if (stats->read_holdtime.nr)
 579                 namelen += 2;
 580
 581         for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
 582                 char sym[KSYM_SYMBOL_LEN];
 583                 char ip[32];
 584
 585                 if (class->contention_point[i] == 0)
 586                         break;
 587
 588                 if (!i)
 589                         seq_line(m, '-', 40-namelen, namelen);
 590
 591                 sprint_symbol(sym, class->contention_point[i]);
 592                 snprintf(ip, sizeof(ip), "[<%p>]",
 593                                 (void *)class->contention_point[i]);
 594                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 595                                 stats->contention_point[i],
 596                                 ip, sym);
 597         }
 598         if (i) {
 599                 seq_puts(m, "\n");
 600                 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
 601                 seq_puts(m, "\n");
 602         }
 603 }
 604
 605 static void seq_header(struct seq_file *m)
 606 {
 607         seq_printf(m, "lock_stat version 0.2\n");
 608         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 609         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
 610                         "%14s %14s\n",
 611                         "class name",
 612                         "con-bounces",
 613                         "contentions",
 614                         "waittime-min",
 615                         "waittime-max",
 616                         "waittime-total",
 617                         "acq-bounces",
 618                         "acquisitions",
 619                         "holdtime-min",
 620                         "holdtime-max",
 621                         "holdtime-total");
 622         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 623         seq_printf(m, "\n");
 624 }
 625
 626 static void *ls_start(struct seq_file *m, loff_t *pos)
 627 {
 628         struct lock_stat_seq *data = m->private;
 629
 630         if (*pos == 0)
 631                 return SEQ_START_TOKEN;
 632
 633         data->iter = data->stats + *pos;
 634         if (data->iter >= data->iter_end)
 635                 data->iter = NULL;
 636
 637         return data->iter;
 638 }
 639
 640 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 641 {
 642         struct lock_stat_seq *data = m->private;
 643
 644         (*pos)++;
 645
 646         if (v == SEQ_START_TOKEN)
 647                 data->iter = data->stats;
 648         else {
 649                 data->iter = v;
 650                 data->iter++;
 651         }
 652
 653         if (data->iter == data->iter_end)
 654                 data->iter = NULL;
 655
 656         return data->iter;
 657 }
 658
 659 static void ls_stop(struct seq_file *m, void *v)
 660 {
 661 }
 662
 663 static int ls_show(struct seq_file *m, void *v)
 664 {
 665         if (v == SEQ_START_TOKEN)
 666                 seq_header(m);
 667         else
 668                 seq_stats(m, v);
 669
 670         return 0;
 671 }
 672
 673 static struct seq_operations lockstat_ops = {
 674         .start  = ls_start,
 675         .next   = ls_next,
 676         .stop   = ls_stop,
 677         .show   = ls_show,
 678 };
 679
 680 static int lock_stat_open(struct inode *inode, struct file *file)
 681 {
 682         int res;
 683         struct lock_class *class;
 684         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
 685
 686         if (!data)
 687                 return -ENOMEM;
 688
 689         res = seq_open(file, &lockstat_ops);
 690         if (!res) {
 691                 struct lock_stat_data *iter = data->stats;
 692                 struct seq_file *m = file->private_data;
 693
 694                 data->iter = iter;
 695                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
 696                         iter->class = class;
 697                         iter->stats = lock_stats(class);
 698                         iter++;
 699                 }
 700                 data->iter_end = iter;
 701
 702                 sort(data->stats, data->iter_end - data->iter,
 703                                 sizeof(struct lock_stat_data),
 704                                 lock_stat_cmp, NULL);
 705
 706                 m->private = data;
 707         } else
 708                 vfree(data);
 709
 710         return res;
 711 }
 712
 713 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
 714                                size_t count, loff_t *ppos)
 715 {
 716         struct lock_class *class;
 717         char c;
 718
 719         if (count) {
 720                 if (get_user(c, buf))
 721                         return -EFAULT;
 722
 723                 if (c != '0')
 724                         return count;
 725
 726                 list_for_each_entry(class, &all_lock_classes, lock_entry)
 727                         clear_lock_stats(class);
 728         }
 729         return count;
 730 }
 731
 732 static int lock_stat_release(struct inode *inode, struct file *file)
 733 {
 734         struct seq_file *seq = file->private_data;
 735
 736         vfree(seq->private);
 737         seq->private = NULL;
 738         return seq_release(inode, file);
 739 }
 740
 741 static const struct file_operations proc_lock_stat_operations = {
 742         .open           = lock_stat_open,
 743         .write          = lock_stat_write,
 744         .read           = seq_read,
 745         .llseek         = seq_lseek,
 746         .release        = lock_stat_release,
 747 };
 748 #endif /* CONFIG_LOCK_STAT */
 749
 750 static int __init lockdep_proc_init(void)
 751 {
 752         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
 753         proc_create("lockdep_chains", S_IRUSR, NULL,
 754                     &proc_lockdep_chains_operations);
 755         proc_create("lockdep_stats", S_IRUSR, NULL,
 756                     &proc_lockdep_stats_operations);
 757
 758 #ifdef CONFIG_LOCK_STAT
 759         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
 760 #endif
 761
 762         return 0;
 763 }
 764
 765 __initcall(lockdep_proc_init);
 766