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         return seq_list_next(v, &all_lock_classes, pos);
  29 }
  30
  31 static void *l_start(struct seq_file *m, loff_t *pos)
  32 {
  33         return seq_list_start_head(&all_lock_classes, *pos);
  34 }
  35
  36 static void l_stop(struct seq_file *m, void *v)
  37 {
  38 }
  39
  40 static void print_name(struct seq_file *m, struct lock_class *class)
  41 {
  42         char str[128];
  43         const char *name = class->name;
  44
  45         if (!name) {
  46                 name = __get_key_name(class->key, str);
  47                 seq_printf(m, "%s", name);
  48         } else{
  49                 seq_printf(m, "%s", name);
  50                 if (class->name_version > 1)
  51                         seq_printf(m, "#%d", class->name_version);
  52                 if (class->subclass)
  53                         seq_printf(m, "/%d", class->subclass);
  54         }
  55 }
  56
  57 static int l_show(struct seq_file *m, void *v)
  58 {
  59         struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
  60         struct lock_list *entry;
  61         char usage[LOCK_USAGE_CHARS];
  62
  63         if (v == &all_lock_classes) {
  64                 seq_printf(m, "all lock classes:\n");
  65                 return 0;
  66         }
  67
  68         seq_printf(m, "%p", class->key);
  69 #ifdef CONFIG_DEBUG_LOCKDEP
  70         seq_printf(m, " OPS:%8ld", class->ops);
  71 #endif
  72 #ifdef CONFIG_PROVE_LOCKING
  73         seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
  74         seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
  75 #endif
  76
  77         get_usage_chars(class, usage);
  78         seq_printf(m, " %s", usage);
  79
  80         seq_printf(m, ": ");
  81         print_name(m, class);
  82         seq_puts(m, "\n");
  83
  84         list_for_each_entry(entry, &class->locks_after, entry) {
  85                 if (entry->distance == 1) {
  86                         seq_printf(m, " -> [%p] ", entry->class->key);
  87                         print_name(m, entry->class);
  88                         seq_puts(m, "\n");
  89                 }
  90         }
  91         seq_puts(m, "\n");
  92
  93         return 0;
  94 }
  95
  96 static const struct seq_operations lockdep_ops = {
  97         .start  = l_start,
  98         .next   = l_next,
  99         .stop   = l_stop,
 100         .show   = l_show,
 101 };
 102
 103 static int lockdep_open(struct inode *inode, struct file *file)
 104 {
 105         return seq_open(file, &lockdep_ops);
 106 }
 107
 108 static const struct file_operations proc_lockdep_operations = {
 109         .open           = lockdep_open,
 110         .read           = seq_read,
 111         .llseek         = seq_lseek,
 112         .release        = seq_release,
 113 };
 114
 115 #ifdef CONFIG_PROVE_LOCKING
 116 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
 117 {
 118         struct lock_chain *chain;
 119
 120         (*pos)++;
 121
 122         if (v == SEQ_START_TOKEN)
 123                 chain = m->private;
 124         else {
 125                 chain = v;
 126
 127                 if (*pos - 1 < nr_lock_chains)
 128                         chain = lock_chains + (*pos - 1);
 129                 else
 130                         chain = NULL;
 131         }
 132
 133         return chain;
 134 }
 135
 136 static void *lc_start(struct seq_file *m, loff_t *pos)
 137 {
 138         if (*pos == 0)
 139                 return SEQ_START_TOKEN;
 140
 141         if (*pos - 1 < nr_lock_chains)
 142                 return lock_chains + (*pos - 1);
 143
 144         return NULL;
 145 }
 146
 147 static void lc_stop(struct seq_file *m, void *v)
 148 {
 149 }
 150
 151 static int lc_show(struct seq_file *m, void *v)
 152 {
 153         struct lock_chain *chain = v;
 154         struct lock_class *class;
 155         int i;
 156
 157         if (v == SEQ_START_TOKEN) {
 158                 seq_printf(m, "all lock chains:\n");
 159                 return 0;
 160         }
 161
 162         seq_printf(m, "irq_context: %d\n", chain->irq_context);
 163
 164         for (i = 0; i < chain->depth; i++) {
 165                 class = lock_chain_get_class(chain, i);
 166                 if (!class->key)
 167                         continue;
 168
 169                 seq_printf(m, "[%p] ", class->key);
 170                 print_name(m, class);
 171                 seq_puts(m, "\n");
 172         }
 173         seq_puts(m, "\n");
 174
 175         return 0;
 176 }
 177
 178 static const struct seq_operations lockdep_chains_ops = {
 179         .start  = lc_start,
 180         .next   = lc_next,
 181         .stop   = lc_stop,
 182         .show   = lc_show,
 183 };
 184
 185 static int lockdep_chains_open(struct inode *inode, struct file *file)
 186 {
 187         int res = seq_open(file, &lockdep_chains_ops);
 188         if (!res) {
 189                 struct seq_file *m = file->private_data;
 190
 191                 if (nr_lock_chains)
 192                         m->private = lock_chains;
 193                 else
 194                         m->private = NULL;
 195         }
 196         return res;
 197 }
 198
 199 static const struct file_operations proc_lockdep_chains_operations = {
 200         .open           = lockdep_chains_open,
 201         .read           = seq_read,
 202         .llseek         = seq_lseek,
 203         .release        = seq_release,
 204 };
 205 #endif /* CONFIG_PROVE_LOCKING */
 206
 207 static void lockdep_stats_debug_show(struct seq_file *m)
 208 {
 209 #ifdef CONFIG_DEBUG_LOCKDEP
 210         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 211                      hi2 = debug_atomic_read(&hardirqs_off_events),
 212                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 213                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 214                      si1 = debug_atomic_read(&softirqs_on_events),
 215                      si2 = debug_atomic_read(&softirqs_off_events),
 216                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 217                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 218
 219         seq_printf(m, " chain lookup misses:           %11u\n",
 220                 debug_atomic_read(&chain_lookup_misses));
 221         seq_printf(m, " chain lookup hits:             %11u\n",
 222                 debug_atomic_read(&chain_lookup_hits));
 223         seq_printf(m, " cyclic checks:                 %11u\n",
 224                 debug_atomic_read(&nr_cyclic_checks));
 225         seq_printf(m, " cyclic-check recursions:       %11u\n",
 226                 debug_atomic_read(&nr_cyclic_check_recursions));
 227         seq_printf(m, " find-mask forwards checks:     %11u\n",
 228                 debug_atomic_read(&nr_find_usage_forwards_checks));
 229         seq_printf(m, " find-mask forwards recursions: %11u\n",
 230                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 231         seq_printf(m, " find-mask backwards checks:    %11u\n",
 232                 debug_atomic_read(&nr_find_usage_backwards_checks));
 233         seq_printf(m, " find-mask backwards recursions:%11u\n",
 234                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 235
 236         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 237         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 238         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 239         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 240         seq_printf(m, " softirq on events:             %11u\n", si1);
 241         seq_printf(m, " softirq off events:            %11u\n", si2);
 242         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 243         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 244 #endif
 245 }
 246
 247 static int lockdep_stats_show(struct seq_file *m, void *v)
 248 {
 249         struct lock_class *class;
 250         unsigned long nr_unused = 0, nr_uncategorized = 0,
 251                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 252                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 253                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 254                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 255                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 256                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 257                       sum_forward_deps = 0, factor = 0;
 258
 259         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 260
 261                 if (class->usage_mask == 0)
 262                         nr_unused++;
 263                 if (class->usage_mask == LOCKF_USED)
 264                         nr_uncategorized++;
 265                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 266                         nr_irq_safe++;
 267                 if (class->usage_mask & LOCKF_ENABLED_IRQ)
 268                         nr_irq_unsafe++;
 269                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 270                         nr_softirq_safe++;
 271                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
 272                         nr_softirq_unsafe++;
 273                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 274                         nr_hardirq_safe++;
 275                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
 276                         nr_hardirq_unsafe++;
 277                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 278                         nr_irq_read_safe++;
 279                 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
 280                         nr_irq_read_unsafe++;
 281                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 282                         nr_softirq_read_safe++;
 283                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
 284                         nr_softirq_read_unsafe++;
 285                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 286                         nr_hardirq_read_safe++;
 287                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
 288                         nr_hardirq_read_unsafe++;
 289
 290 #ifdef CONFIG_PROVE_LOCKING
 291                 sum_forward_deps += lockdep_count_forward_deps(class);
 292 #endif
 293         }
 294 #ifdef CONFIG_DEBUG_LOCKDEP
 295         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 296 #endif
 297         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 298                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 299         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 300                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 301         seq_printf(m, " indirect dependencies:         %11lu\n",
 302                         sum_forward_deps);
 303
 304         /*
 305          * Total number of dependencies:
 306          *
 307          * All irq-safe locks may nest inside irq-unsafe locks,
 308          * plus all the other known dependencies:
 309          */
 310         seq_printf(m, " all direct dependencies:       %11lu\n",
 311                         nr_irq_unsafe * nr_irq_safe +
 312                         nr_hardirq_unsafe * nr_hardirq_safe +
 313                         nr_list_entries);
 314
 315         /*
 316          * Estimated factor between direct and indirect
 317          * dependencies:
 318          */
 319         if (nr_list_entries)
 320                 factor = sum_forward_deps / nr_list_entries;
 321
 322 #ifdef CONFIG_PROVE_LOCKING
 323         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 324                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 325         seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
 326                         nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
 327 #endif
 328
 329 #ifdef CONFIG_TRACE_IRQFLAGS
 330         seq_printf(m, " in-hardirq chains:             %11u\n",
 331                         nr_hardirq_chains);
 332         seq_printf(m, " in-softirq chains:             %11u\n",
 333                         nr_softirq_chains);
 334 #endif
 335         seq_printf(m, " in-process chains:             %11u\n",
 336                         nr_process_chains);
 337         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 338                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 339         seq_printf(m, " combined max dependencies:     %11u\n",
 340                         (nr_hardirq_chains + 1) *
 341                         (nr_softirq_chains + 1) *
 342                         (nr_process_chains + 1)
 343         );
 344         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 345                         nr_hardirq_safe);
 346         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 347                         nr_hardirq_unsafe);
 348         seq_printf(m, " softirq-safe locks:            %11lu\n",
 349                         nr_softirq_safe);
 350         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 351                         nr_softirq_unsafe);
 352         seq_printf(m, " irq-safe locks:                %11lu\n",
 353                         nr_irq_safe);
 354         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 355                         nr_irq_unsafe);
 356
 357         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 358                         nr_hardirq_read_safe);
 359         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 360                         nr_hardirq_read_unsafe);
 361         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 362                         nr_softirq_read_safe);
 363         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 364                         nr_softirq_read_unsafe);
 365         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 366                         nr_irq_read_safe);
 367         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 368                         nr_irq_read_unsafe);
 369
 370         seq_printf(m, " uncategorized locks:           %11lu\n",
 371                         nr_uncategorized);
 372         seq_printf(m, " unused locks:                  %11lu\n",
 373                         nr_unused);
 374         seq_printf(m, " max locking depth:             %11u\n",
 375                         max_lockdep_depth);
 376         seq_printf(m, " max recursion depth:           %11u\n",
 377                         max_recursion_depth);
 378 #ifdef CONFIG_PROVE_LOCKING
 379         seq_printf(m, " max bfs queue depth:           %11u\n",
 380                         max_bfs_queue_depth);
 381 #endif
 382         lockdep_stats_debug_show(m);
 383         seq_printf(m, " debug_locks:                   %11u\n",
 384                         debug_locks);
 385
 386         return 0;
 387 }
 388
 389 static int lockdep_stats_open(struct inode *inode, struct file *file)
 390 {
 391         return single_open(file, lockdep_stats_show, NULL);
 392 }
 393
 394 static const struct file_operations proc_lockdep_stats_operations = {
 395         .open           = lockdep_stats_open,
 396         .read           = seq_read,
 397         .llseek         = seq_lseek,
 398         .release        = single_release,
 399 };
 400
 401 #ifdef CONFIG_LOCK_STAT
 402
 403 struct lock_stat_data {
 404         struct lock_class *class;
 405         struct lock_class_stats stats;
 406 };
 407
 408 struct lock_stat_seq {
 409         struct lock_stat_data *iter;
 410         struct lock_stat_data *iter_end;
 411         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 412 };
 413
 414 /*
 415  * sort on absolute number of contentions
 416  */
 417 static int lock_stat_cmp(const void *l, const void *r)
 418 {
 419         const struct lock_stat_data *dl = l, *dr = r;
 420         unsigned long nl, nr;
 421
 422         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 423         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 424
 425         return nr - nl;
 426 }
 427
 428 static void seq_line(struct seq_file *m, char c, int offset, int length)
 429 {
 430         int i;
 431
 432         for (i = 0; i < offset; i++)
 433                 seq_puts(m, " ");
 434         for (i = 0; i < length; i++)
 435                 seq_printf(m, "%c", c);
 436         seq_puts(m, "\n");
 437 }
 438
 439 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 440 {
 441         s64 div;
 442         s32 rem;
 443
 444         nr += 5; /* for display rounding */
 445         div = div_s64_rem(nr, 1000, &rem);
 446         snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
 447 }
 448
 449 static void seq_time(struct seq_file *m, s64 time)
 450 {
 451         char num[15];
 452
 453         snprint_time(num, sizeof(num), time);
 454         seq_printf(m, " %14s", num);
 455 }
 456
 457 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 458 {
 459         seq_printf(m, "%14lu", lt->nr);
 460         seq_time(m, lt->min);
 461         seq_time(m, lt->max);
 462         seq_time(m, lt->total);
 463 }
 464
 465 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 466 {
 467         char name[39];
 468         struct lock_class *class;
 469         struct lock_class_stats *stats;
 470         int i, namelen;
 471
 472         class = data->class;
 473         stats = &data->stats;
 474
 475         namelen = 38;
 476         if (class->name_version > 1)
 477                 namelen -= 2; /* XXX truncates versions > 9 */
 478         if (class->subclass)
 479                 namelen -= 2;
 480
 481         if (!class->name) {
 482                 char str[KSYM_NAME_LEN];
 483                 const char *key_name;
 484
 485                 key_name = __get_key_name(class->key, str);
 486                 snprintf(name, namelen, "%s", key_name);
 487         } else {
 488                 snprintf(name, namelen, "%s", class->name);
 489         }
 490         namelen = strlen(name);
 491         if (class->name_version > 1) {
 492                 snprintf(name+namelen, 3, "#%d", class->name_version);
 493                 namelen += 2;
 494         }
 495         if (class->subclass) {
 496                 snprintf(name+namelen, 3, "/%d", class->subclass);
 497                 namelen += 2;
 498         }
 499
 500         if (stats->write_holdtime.nr) {
 501                 if (stats->read_holdtime.nr)
 502                         seq_printf(m, "%38s-W:", name);
 503                 else
 504                         seq_printf(m, "%40s:", name);
 505
 506                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
 507                 seq_lock_time(m, &stats->write_waittime);
 508                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
 509                 seq_lock_time(m, &stats->write_holdtime);
 510                 seq_puts(m, "\n");
 511         }
 512
 513         if (stats->read_holdtime.nr) {
 514                 seq_printf(m, "%38s-R:", name);
 515                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
 516                 seq_lock_time(m, &stats->read_waittime);
 517                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
 518                 seq_lock_time(m, &stats->read_holdtime);
 519                 seq_puts(m, "\n");
 520         }
 521
 522         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 523                 return;
 524
 525         if (stats->read_holdtime.nr)
 526                 namelen += 2;
 527
 528         for (i = 0; i < LOCKSTAT_POINTS; i++) {
 529                 char sym[KSYM_SYMBOL_LEN];
 530                 char ip[32];
 531
 532                 if (class->contention_point[i] == 0)
 533                         break;
 534
 535                 if (!i)
 536                         seq_line(m, '-', 40-namelen, namelen);
 537
 538                 sprint_symbol(sym, class->contention_point[i]);
 539                 snprintf(ip, sizeof(ip), "[<%p>]",
 540                                 (void *)class->contention_point[i]);
 541                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 542                                 stats->contention_point[i],
 543                                 ip, sym);
 544         }
 545         for (i = 0; i < LOCKSTAT_POINTS; i++) {
 546                 char sym[KSYM_SYMBOL_LEN];
 547                 char ip[32];
 548
 549                 if (class->contending_point[i] == 0)
 550                         break;
 551
 552                 if (!i)
 553                         seq_line(m, '-', 40-namelen, namelen);
 554
 555                 sprint_symbol(sym, class->contending_point[i]);
 556                 snprintf(ip, sizeof(ip), "[<%p>]",
 557                                 (void *)class->contending_point[i]);
 558                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 559                                 stats->contending_point[i],
 560                                 ip, sym);
 561         }
 562         if (i) {
 563                 seq_puts(m, "\n");
 564                 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
 565                 seq_puts(m, "\n");
 566         }
 567 }
 568
 569 static void seq_header(struct seq_file *m)
 570 {
 571         seq_printf(m, "lock_stat version 0.3\n");
 572
 573         if (unlikely(!debug_locks))
 574                 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
 575
 576         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 577         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
 578                         "%14s %14s\n",
 579                         "class name",
 580                         "con-bounces",
 581                         "contentions",
 582                         "waittime-min",
 583                         "waittime-max",
 584                         "waittime-total",
 585                         "acq-bounces",
 586                         "acquisitions",
 587                         "holdtime-min",
 588                         "holdtime-max",
 589                         "holdtime-total");
 590         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 591         seq_printf(m, "\n");
 592 }
 593
 594 static void *ls_start(struct seq_file *m, loff_t *pos)
 595 {
 596         struct lock_stat_seq *data = m->private;
 597
 598         if (*pos == 0)
 599                 return SEQ_START_TOKEN;
 600
 601         data->iter = data->stats + (*pos - 1);
 602         if (data->iter >= data->iter_end)
 603                 data->iter = NULL;
 604
 605         return data->iter;
 606 }
 607
 608 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 609 {
 610         struct lock_stat_seq *data = m->private;
 611
 612         (*pos)++;
 613
 614         if (v == SEQ_START_TOKEN)
 615                 data->iter = data->stats;
 616         else {
 617                 data->iter = v;
 618                 data->iter++;
 619         }
 620
 621         if (data->iter == data->iter_end)
 622                 data->iter = NULL;
 623
 624         return data->iter;
 625 }
 626
 627 static void ls_stop(struct seq_file *m, void *v)
 628 {
 629 }
 630
 631 static int ls_show(struct seq_file *m, void *v)
 632 {
 633         if (v == SEQ_START_TOKEN)
 634                 seq_header(m);
 635         else
 636                 seq_stats(m, v);
 637
 638         return 0;
 639 }
 640
 641 static struct seq_operations lockstat_ops = {
 642         .start  = ls_start,
 643         .next   = ls_next,
 644         .stop   = ls_stop,
 645         .show   = ls_show,
 646 };
 647
 648 static int lock_stat_open(struct inode *inode, struct file *file)
 649 {
 650         int res;
 651         struct lock_class *class;
 652         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
 653
 654         if (!data)
 655                 return -ENOMEM;
 656
 657         res = seq_open(file, &lockstat_ops);
 658         if (!res) {
 659                 struct lock_stat_data *iter = data->stats;
 660                 struct seq_file *m = file->private_data;
 661
 662                 data->iter = iter;
 663                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
 664                         iter->class = class;
 665                         iter->stats = lock_stats(class);
 666                         iter++;
 667                 }
 668                 data->iter_end = iter;
 669
 670                 sort(data->stats, data->iter_end - data->iter,
 671                                 sizeof(struct lock_stat_data),
 672                                 lock_stat_cmp, NULL);
 673
 674                 m->private = data;
 675         } else
 676                 vfree(data);
 677
 678         return res;
 679 }
 680
 681 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
 682                                size_t count, loff_t *ppos)
 683 {
 684         struct lock_class *class;
 685         char c;
 686
 687         if (count) {
 688                 if (get_user(c, buf))
 689                         return -EFAULT;
 690
 691                 if (c != '0')
 692                         return count;
 693
 694                 list_for_each_entry(class, &all_lock_classes, lock_entry)
 695                         clear_lock_stats(class);
 696         }
 697         return count;
 698 }
 699
 700 static int lock_stat_release(struct inode *inode, struct file *file)
 701 {
 702         struct seq_file *seq = file->private_data;
 703
 704         vfree(seq->private);
 705         seq->private = NULL;
 706         return seq_release(inode, file);
 707 }
 708
 709 static const struct file_operations proc_lock_stat_operations = {
 710         .open           = lock_stat_open,
 711         .write          = lock_stat_write,
 712         .read           = seq_read,
 713         .llseek         = seq_lseek,
 714         .release        = lock_stat_release,
 715 };
 716 #endif /* CONFIG_LOCK_STAT */
 717
 718 static int __init lockdep_proc_init(void)
 719 {
 720         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
 721 #ifdef CONFIG_PROVE_LOCKING
 722         proc_create("lockdep_chains", S_IRUSR, NULL,
 723                     &proc_lockdep_chains_operations);
 724 #endif
 725         proc_create("lockdep_stats", S_IRUSR, NULL,
 726                     &proc_lockdep_stats_operations);
 727
 728 #ifdef CONFIG_LOCK_STAT
 729         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
 730 #endif
 731
 732         return 0;
 733 }
 734
 735 __initcall(lockdep_proc_init);
 736