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   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 void print_name(struct seq_file *m, struct lock_class *class)
  67 {
  68         char str[128];
  69         const char *name = class->name;
  70
  71         if (!name) {
  72                 name = __get_key_name(class->key, str);
  73                 seq_printf(m, "%s", name);
  74         } else{
  75                 seq_printf(m, "%s", name);
  76                 if (class->name_version > 1)
  77                         seq_printf(m, "#%d", class->name_version);
  78                 if (class->subclass)
  79                         seq_printf(m, "/%d", class->subclass);
  80         }
  81 }
  82
  83 static int l_show(struct seq_file *m, void *v)
  84 {
  85         struct lock_class *class = v;
  86         struct lock_list *entry;
  87         char usage[LOCK_USAGE_CHARS];
  88
  89         if (v == SEQ_START_TOKEN) {
  90                 seq_printf(m, "all lock classes:\n");
  91                 return 0;
  92         }
  93
  94         seq_printf(m, "%p", class->key);
  95 #ifdef CONFIG_DEBUG_LOCKDEP
  96         seq_printf(m, " OPS:%8ld", class->ops);
  97 #endif
  98 #ifdef CONFIG_PROVE_LOCKING
  99         seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
 100         seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
 101 #endif
 102
 103         get_usage_chars(class, usage);
 104         seq_printf(m, " %s", usage);
 105
 106         seq_printf(m, ": ");
 107         print_name(m, class);
 108         seq_puts(m, "\n");
 109
 110         list_for_each_entry(entry, &class->locks_after, entry) {
 111                 if (entry->distance == 1) {
 112                         seq_printf(m, " -> [%p] ", entry->class->key);
 113                         print_name(m, entry->class);
 114                         seq_puts(m, "\n");
 115                 }
 116         }
 117         seq_puts(m, "\n");
 118
 119         return 0;
 120 }
 121
 122 static const struct seq_operations lockdep_ops = {
 123         .start  = l_start,
 124         .next   = l_next,
 125         .stop   = l_stop,
 126         .show   = l_show,
 127 };
 128
 129 static int lockdep_open(struct inode *inode, struct file *file)
 130 {
 131         int res = seq_open(file, &lockdep_ops);
 132         if (!res) {
 133                 struct seq_file *m = file->private_data;
 134
 135                 if (!list_empty(&all_lock_classes))
 136                         m->private = list_entry(all_lock_classes.next,
 137                                         struct lock_class, lock_entry);
 138                 else
 139                         m->private = NULL;
 140         }
 141         return res;
 142 }
 143
 144 static const struct file_operations proc_lockdep_operations = {
 145         .open           = lockdep_open,
 146         .read           = seq_read,
 147         .llseek         = seq_lseek,
 148         .release        = seq_release,
 149 };
 150
 151 #ifdef CONFIG_PROVE_LOCKING
 152 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
 153 {
 154         struct lock_chain *chain;
 155
 156         (*pos)++;
 157
 158         if (v == SEQ_START_TOKEN)
 159                 chain = m->private;
 160         else {
 161                 chain = v;
 162
 163                 if (*pos < nr_lock_chains)
 164                         chain = lock_chains + *pos;
 165                 else
 166                         chain = NULL;
 167         }
 168
 169         return chain;
 170 }
 171
 172 static void *lc_start(struct seq_file *m, loff_t *pos)
 173 {
 174         if (*pos == 0)
 175                 return SEQ_START_TOKEN;
 176
 177         if (*pos < nr_lock_chains)
 178                 return lock_chains + *pos;
 179
 180         return NULL;
 181 }
 182
 183 static void lc_stop(struct seq_file *m, void *v)
 184 {
 185 }
 186
 187 static int lc_show(struct seq_file *m, void *v)
 188 {
 189         struct lock_chain *chain = v;
 190         struct lock_class *class;
 191         int i;
 192
 193         if (v == SEQ_START_TOKEN) {
 194                 seq_printf(m, "all lock chains:\n");
 195                 return 0;
 196         }
 197
 198         seq_printf(m, "irq_context: %d\n", chain->irq_context);
 199
 200         for (i = 0; i < chain->depth; i++) {
 201                 class = lock_chain_get_class(chain, i);
 202                 if (!class->key)
 203                         continue;
 204
 205                 seq_printf(m, "[%p] ", class->key);
 206                 print_name(m, class);
 207                 seq_puts(m, "\n");
 208         }
 209         seq_puts(m, "\n");
 210
 211         return 0;
 212 }
 213
 214 static const struct seq_operations lockdep_chains_ops = {
 215         .start  = lc_start,
 216         .next   = lc_next,
 217         .stop   = lc_stop,
 218         .show   = lc_show,
 219 };
 220
 221 static int lockdep_chains_open(struct inode *inode, struct file *file)
 222 {
 223         int res = seq_open(file, &lockdep_chains_ops);
 224         if (!res) {
 225                 struct seq_file *m = file->private_data;
 226
 227                 if (nr_lock_chains)
 228                         m->private = lock_chains;
 229                 else
 230                         m->private = NULL;
 231         }
 232         return res;
 233 }
 234
 235 static const struct file_operations proc_lockdep_chains_operations = {
 236         .open           = lockdep_chains_open,
 237         .read           = seq_read,
 238         .llseek         = seq_lseek,
 239         .release        = seq_release,
 240 };
 241 #endif /* CONFIG_PROVE_LOCKING */
 242
 243 static void lockdep_stats_debug_show(struct seq_file *m)
 244 {
 245 #ifdef CONFIG_DEBUG_LOCKDEP
 246         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 247                      hi2 = debug_atomic_read(&hardirqs_off_events),
 248                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 249                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 250                      si1 = debug_atomic_read(&softirqs_on_events),
 251                      si2 = debug_atomic_read(&softirqs_off_events),
 252                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 253                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 254
 255         seq_printf(m, " chain lookup misses:           %11u\n",
 256                 debug_atomic_read(&chain_lookup_misses));
 257         seq_printf(m, " chain lookup hits:             %11u\n",
 258                 debug_atomic_read(&chain_lookup_hits));
 259         seq_printf(m, " cyclic checks:                 %11u\n",
 260                 debug_atomic_read(&nr_cyclic_checks));
 261         seq_printf(m, " cyclic-check recursions:       %11u\n",
 262                 debug_atomic_read(&nr_cyclic_check_recursions));
 263         seq_printf(m, " find-mask forwards checks:     %11u\n",
 264                 debug_atomic_read(&nr_find_usage_forwards_checks));
 265         seq_printf(m, " find-mask forwards recursions: %11u\n",
 266                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 267         seq_printf(m, " find-mask backwards checks:    %11u\n",
 268                 debug_atomic_read(&nr_find_usage_backwards_checks));
 269         seq_printf(m, " find-mask backwards recursions:%11u\n",
 270                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 271
 272         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 273         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 274         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 275         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 276         seq_printf(m, " softirq on events:             %11u\n", si1);
 277         seq_printf(m, " softirq off events:            %11u\n", si2);
 278         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 279         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 280 #endif
 281 }
 282
 283 static int lockdep_stats_show(struct seq_file *m, void *v)
 284 {
 285         struct lock_class *class;
 286         unsigned long nr_unused = 0, nr_uncategorized = 0,
 287                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 288                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 289                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 290                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 291                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 292                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 293                       sum_forward_deps = 0, factor = 0;
 294
 295         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 296
 297                 if (class->usage_mask == 0)
 298                         nr_unused++;
 299                 if (class->usage_mask == LOCKF_USED)
 300                         nr_uncategorized++;
 301                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 302                         nr_irq_safe++;
 303                 if (class->usage_mask & LOCKF_ENABLED_IRQ)
 304                         nr_irq_unsafe++;
 305                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 306                         nr_softirq_safe++;
 307                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
 308                         nr_softirq_unsafe++;
 309                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 310                         nr_hardirq_safe++;
 311                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
 312                         nr_hardirq_unsafe++;
 313                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 314                         nr_irq_read_safe++;
 315                 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
 316                         nr_irq_read_unsafe++;
 317                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 318                         nr_softirq_read_safe++;
 319                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
 320                         nr_softirq_read_unsafe++;
 321                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 322                         nr_hardirq_read_safe++;
 323                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
 324                         nr_hardirq_read_unsafe++;
 325
 326 #ifdef CONFIG_PROVE_LOCKING
 327                 sum_forward_deps += lockdep_count_forward_deps(class);
 328 #endif
 329         }
 330 #ifdef CONFIG_DEBUG_LOCKDEP
 331         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 332 #endif
 333         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 334                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 335         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 336                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 337         seq_printf(m, " indirect dependencies:         %11lu\n",
 338                         sum_forward_deps);
 339
 340         /*
 341          * Total number of dependencies:
 342          *
 343          * All irq-safe locks may nest inside irq-unsafe locks,
 344          * plus all the other known dependencies:
 345          */
 346         seq_printf(m, " all direct dependencies:       %11lu\n",
 347                         nr_irq_unsafe * nr_irq_safe +
 348                         nr_hardirq_unsafe * nr_hardirq_safe +
 349                         nr_list_entries);
 350
 351         /*
 352          * Estimated factor between direct and indirect
 353          * dependencies:
 354          */
 355         if (nr_list_entries)
 356                 factor = sum_forward_deps / nr_list_entries;
 357
 358 #ifdef CONFIG_PROVE_LOCKING
 359         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 360                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 361         seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
 362                         nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
 363 #endif
 364
 365 #ifdef CONFIG_TRACE_IRQFLAGS
 366         seq_printf(m, " in-hardirq chains:             %11u\n",
 367                         nr_hardirq_chains);
 368         seq_printf(m, " in-softirq chains:             %11u\n",
 369                         nr_softirq_chains);
 370 #endif
 371         seq_printf(m, " in-process chains:             %11u\n",
 372                         nr_process_chains);
 373         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 374                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 375         seq_printf(m, " combined max dependencies:     %11u\n",
 376                         (nr_hardirq_chains + 1) *
 377                         (nr_softirq_chains + 1) *
 378                         (nr_process_chains + 1)
 379         );
 380         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 381                         nr_hardirq_safe);
 382         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 383                         nr_hardirq_unsafe);
 384         seq_printf(m, " softirq-safe locks:            %11lu\n",
 385                         nr_softirq_safe);
 386         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 387                         nr_softirq_unsafe);
 388         seq_printf(m, " irq-safe locks:                %11lu\n",
 389                         nr_irq_safe);
 390         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 391                         nr_irq_unsafe);
 392
 393         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 394                         nr_hardirq_read_safe);
 395         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 396                         nr_hardirq_read_unsafe);
 397         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 398                         nr_softirq_read_safe);
 399         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 400                         nr_softirq_read_unsafe);
 401         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 402                         nr_irq_read_safe);
 403         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 404                         nr_irq_read_unsafe);
 405
 406         seq_printf(m, " uncategorized locks:           %11lu\n",
 407                         nr_uncategorized);
 408         seq_printf(m, " unused locks:                  %11lu\n",
 409                         nr_unused);
 410         seq_printf(m, " max locking depth:             %11u\n",
 411                         max_lockdep_depth);
 412         seq_printf(m, " max recursion depth:           %11u\n",
 413                         max_recursion_depth);
 414 #ifdef CONFIG_PROVE_LOCKING
 415         seq_printf(m, " max bfs queue depth:           %11u\n",
 416                         max_bfs_queue_depth);
 417 #endif
 418         lockdep_stats_debug_show(m);
 419         seq_printf(m, " debug_locks:                   %11u\n",
 420                         debug_locks);
 421
 422         return 0;
 423 }
 424
 425 static int lockdep_stats_open(struct inode *inode, struct file *file)
 426 {
 427         return single_open(file, lockdep_stats_show, NULL);
 428 }
 429
 430 static const struct file_operations proc_lockdep_stats_operations = {
 431         .open           = lockdep_stats_open,
 432         .read           = seq_read,
 433         .llseek         = seq_lseek,
 434         .release        = single_release,
 435 };
 436
 437 #ifdef CONFIG_LOCK_STAT
 438
 439 struct lock_stat_data {
 440         struct lock_class *class;
 441         struct lock_class_stats stats;
 442 };
 443
 444 struct lock_stat_seq {
 445         struct lock_stat_data *iter;
 446         struct lock_stat_data *iter_end;
 447         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 448 };
 449
 450 /*
 451  * sort on absolute number of contentions
 452  */
 453 static int lock_stat_cmp(const void *l, const void *r)
 454 {
 455         const struct lock_stat_data *dl = l, *dr = r;
 456         unsigned long nl, nr;
 457
 458         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 459         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 460
 461         return nr - nl;
 462 }
 463
 464 static void seq_line(struct seq_file *m, char c, int offset, int length)
 465 {
 466         int i;
 467
 468         for (i = 0; i < offset; i++)
 469                 seq_puts(m, " ");
 470         for (i = 0; i < length; i++)
 471                 seq_printf(m, "%c", c);
 472         seq_puts(m, "\n");
 473 }
 474
 475 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 476 {
 477         s64 div;
 478         s32 rem;
 479
 480         nr += 5; /* for display rounding */
 481         div = div_s64_rem(nr, 1000, &rem);
 482         snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
 483 }
 484
 485 static void seq_time(struct seq_file *m, s64 time)
 486 {
 487         char num[15];
 488
 489         snprint_time(num, sizeof(num), time);
 490         seq_printf(m, " %14s", num);
 491 }
 492
 493 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 494 {
 495         seq_printf(m, "%14lu", lt->nr);
 496         seq_time(m, lt->min);
 497         seq_time(m, lt->max);
 498         seq_time(m, lt->total);
 499 }
 500
 501 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 502 {
 503         char name[39];
 504         struct lock_class *class;
 505         struct lock_class_stats *stats;
 506         int i, namelen;
 507
 508         class = data->class;
 509         stats = &data->stats;
 510
 511         namelen = 38;
 512         if (class->name_version > 1)
 513                 namelen -= 2; /* XXX truncates versions > 9 */
 514         if (class->subclass)
 515                 namelen -= 2;
 516
 517         if (!class->name) {
 518                 char str[KSYM_NAME_LEN];
 519                 const char *key_name;
 520
 521                 key_name = __get_key_name(class->key, str);
 522                 snprintf(name, namelen, "%s", key_name);
 523         } else {
 524                 snprintf(name, namelen, "%s", class->name);
 525         }
 526         namelen = strlen(name);
 527         if (class->name_version > 1) {
 528                 snprintf(name+namelen, 3, "#%d", class->name_version);
 529                 namelen += 2;
 530         }
 531         if (class->subclass) {
 532                 snprintf(name+namelen, 3, "/%d", class->subclass);
 533                 namelen += 2;
 534         }
 535
 536         if (stats->write_holdtime.nr) {
 537                 if (stats->read_holdtime.nr)
 538                         seq_printf(m, "%38s-W:", name);
 539                 else
 540                         seq_printf(m, "%40s:", name);
 541
 542                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
 543                 seq_lock_time(m, &stats->write_waittime);
 544                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
 545                 seq_lock_time(m, &stats->write_holdtime);
 546                 seq_puts(m, "\n");
 547         }
 548
 549         if (stats->read_holdtime.nr) {
 550                 seq_printf(m, "%38s-R:", name);
 551                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
 552                 seq_lock_time(m, &stats->read_waittime);
 553                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
 554                 seq_lock_time(m, &stats->read_holdtime);
 555                 seq_puts(m, "\n");
 556         }
 557
 558         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 559                 return;
 560
 561         if (stats->read_holdtime.nr)
 562                 namelen += 2;
 563
 564         for (i = 0; i < LOCKSTAT_POINTS; i++) {
 565                 char sym[KSYM_SYMBOL_LEN];
 566                 char ip[32];
 567
 568                 if (class->contention_point[i] == 0)
 569                         break;
 570
 571                 if (!i)
 572                         seq_line(m, '-', 40-namelen, namelen);
 573
 574                 sprint_symbol(sym, class->contention_point[i]);
 575                 snprintf(ip, sizeof(ip), "[<%p>]",
 576                                 (void *)class->contention_point[i]);
 577                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 578                                 stats->contention_point[i],
 579                                 ip, sym);
 580         }
 581         for (i = 0; i < LOCKSTAT_POINTS; i++) {
 582                 char sym[KSYM_SYMBOL_LEN];
 583                 char ip[32];
 584
 585                 if (class->contending_point[i] == 0)
 586                         break;
 587
 588                 if (!i)
 589                         seq_line(m, '-', 40-namelen, namelen);
 590
 591                 sprint_symbol(sym, class->contending_point[i]);
 592                 snprintf(ip, sizeof(ip), "[<%p>]",
 593                                 (void *)class->contending_point[i]);
 594                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 595                                 stats->contending_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 0.3\n");
 608
 609         if (unlikely(!debug_locks))
 610                 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
 611
 612         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 613         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
 614                         "%14s %14s\n",
 615                         "class name",
 616                         "con-bounces",
 617                         "contentions",
 618                         "waittime-min",
 619                         "waittime-max",
 620                         "waittime-total",
 621                         "acq-bounces",
 622                         "acquisitions",
 623                         "holdtime-min",
 624                         "holdtime-max",
 625                         "holdtime-total");
 626         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 627         seq_printf(m, "\n");
 628 }
 629
 630 static void *ls_start(struct seq_file *m, loff_t *pos)
 631 {
 632         struct lock_stat_seq *data = m->private;
 633
 634         if (*pos == 0)
 635                 return SEQ_START_TOKEN;
 636
 637         data->iter = data->stats + *pos;
 638         if (data->iter >= data->iter_end)
 639                 data->iter = NULL;
 640
 641         return data->iter;
 642 }
 643
 644 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 645 {
 646         struct lock_stat_seq *data = m->private;
 647
 648         (*pos)++;
 649
 650         if (v == SEQ_START_TOKEN)
 651                 data->iter = data->stats;
 652         else {
 653                 data->iter = v;
 654                 data->iter++;
 655         }
 656
 657         if (data->iter == data->iter_end)
 658                 data->iter = NULL;
 659
 660         return data->iter;
 661 }
 662
 663 static void ls_stop(struct seq_file *m, void *v)
 664 {
 665 }
 666
 667 static int ls_show(struct seq_file *m, void *v)
 668 {
 669         if (v == SEQ_START_TOKEN)
 670                 seq_header(m);
 671         else
 672                 seq_stats(m, v);
 673
 674         return 0;
 675 }
 676
 677 static struct seq_operations lockstat_ops = {
 678         .start  = ls_start,
 679         .next   = ls_next,
 680         .stop   = ls_stop,
 681         .show   = ls_show,
 682 };
 683
 684 static int lock_stat_open(struct inode *inode, struct file *file)
 685 {
 686         int res;
 687         struct lock_class *class;
 688         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
 689
 690         if (!data)
 691                 return -ENOMEM;
 692
 693         res = seq_open(file, &lockstat_ops);
 694         if (!res) {
 695                 struct lock_stat_data *iter = data->stats;
 696                 struct seq_file *m = file->private_data;
 697
 698                 data->iter = iter;
 699                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
 700                         iter->class = class;
 701                         iter->stats = lock_stats(class);
 702                         iter++;
 703                 }
 704                 data->iter_end = iter;
 705
 706                 sort(data->stats, data->iter_end - data->iter,
 707                                 sizeof(struct lock_stat_data),
 708                                 lock_stat_cmp, NULL);
 709
 710                 m->private = data;
 711         } else
 712                 vfree(data);
 713
 714         return res;
 715 }
 716
 717 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
 718                                size_t count, loff_t *ppos)
 719 {
 720         struct lock_class *class;
 721         char c;
 722
 723         if (count) {
 724                 if (get_user(c, buf))
 725                         return -EFAULT;
 726
 727                 if (c != '0')
 728                         return count;
 729
 730                 list_for_each_entry(class, &all_lock_classes, lock_entry)
 731                         clear_lock_stats(class);
 732         }
 733         return count;
 734 }
 735
 736 static int lock_stat_release(struct inode *inode, struct file *file)
 737 {
 738         struct seq_file *seq = file->private_data;
 739
 740         vfree(seq->private);
 741         seq->private = NULL;
 742         return seq_release(inode, file);
 743 }
 744
 745 static const struct file_operations proc_lock_stat_operations = {
 746         .open           = lock_stat_open,
 747         .write          = lock_stat_write,
 748         .read           = seq_read,
 749         .llseek         = seq_lseek,
 750         .release        = lock_stat_release,
 751 };
 752 #endif /* CONFIG_LOCK_STAT */
 753
 754 static int __init lockdep_proc_init(void)
 755 {
 756         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
 757 #ifdef CONFIG_PROVE_LOCKING
 758         proc_create("lockdep_chains", S_IRUSR, NULL,
 759                     &proc_lockdep_chains_operations);
 760 #endif
 761         proc_create("lockdep_stats", S_IRUSR, NULL,
 762                     &proc_lockdep_stats_operations);
 763
 764 #ifdef CONFIG_LOCK_STAT
 765         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
 766 #endif
 767
 768         return 0;
 769 }
 770
 771 __initcall(lockdep_proc_init);
 772