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 #ifdef CONFIG_PROVE_LOCKING
 182 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
 183 {
 184         struct lock_chain *chain;
 185
 186         (*pos)++;
 187
 188         if (v == SEQ_START_TOKEN)
 189                 chain = m->private;
 190         else {
 191                 chain = v;
 192
 193                 if (*pos < nr_lock_chains)
 194                         chain = lock_chains + *pos;
 195                 else
 196                         chain = NULL;
 197         }
 198
 199         return chain;
 200 }
 201
 202 static void *lc_start(struct seq_file *m, loff_t *pos)
 203 {
 204         if (*pos == 0)
 205                 return SEQ_START_TOKEN;
 206
 207         if (*pos < nr_lock_chains)
 208                 return lock_chains + *pos;
 209
 210         return NULL;
 211 }
 212
 213 static void lc_stop(struct seq_file *m, void *v)
 214 {
 215 }
 216
 217 static int lc_show(struct seq_file *m, void *v)
 218 {
 219         struct lock_chain *chain = v;
 220         struct lock_class *class;
 221         int i;
 222
 223         if (v == SEQ_START_TOKEN) {
 224                 seq_printf(m, "all lock chains:\n");
 225                 return 0;
 226         }
 227
 228         seq_printf(m, "irq_context: %d\n", chain->irq_context);
 229
 230         for (i = 0; i < chain->depth; i++) {
 231                 class = lock_chain_get_class(chain, i);
 232                 seq_printf(m, "[%p] ", class->key);
 233                 print_name(m, class);
 234                 seq_puts(m, "\n");
 235         }
 236         seq_puts(m, "\n");
 237
 238         return 0;
 239 }
 240
 241 static const struct seq_operations lockdep_chains_ops = {
 242         .start  = lc_start,
 243         .next   = lc_next,
 244         .stop   = lc_stop,
 245         .show   = lc_show,
 246 };
 247
 248 static int lockdep_chains_open(struct inode *inode, struct file *file)
 249 {
 250         int res = seq_open(file, &lockdep_chains_ops);
 251         if (!res) {
 252                 struct seq_file *m = file->private_data;
 253
 254                 if (nr_lock_chains)
 255                         m->private = lock_chains;
 256                 else
 257                         m->private = NULL;
 258         }
 259         return res;
 260 }
 261
 262 static const struct file_operations proc_lockdep_chains_operations = {
 263         .open           = lockdep_chains_open,
 264         .read           = seq_read,
 265         .llseek         = seq_lseek,
 266         .release        = seq_release,
 267 };
 268 #endif /* CONFIG_PROVE_LOCKING */
 269
 270 static void lockdep_stats_debug_show(struct seq_file *m)
 271 {
 272 #ifdef CONFIG_DEBUG_LOCKDEP
 273         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 274                      hi2 = debug_atomic_read(&hardirqs_off_events),
 275                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 276                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 277                      si1 = debug_atomic_read(&softirqs_on_events),
 278                      si2 = debug_atomic_read(&softirqs_off_events),
 279                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 280                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 281
 282         seq_printf(m, " chain lookup misses:           %11u\n",
 283                 debug_atomic_read(&chain_lookup_misses));
 284         seq_printf(m, " chain lookup hits:             %11u\n",
 285                 debug_atomic_read(&chain_lookup_hits));
 286         seq_printf(m, " cyclic checks:                 %11u\n",
 287                 debug_atomic_read(&nr_cyclic_checks));
 288         seq_printf(m, " cyclic-check recursions:       %11u\n",
 289                 debug_atomic_read(&nr_cyclic_check_recursions));
 290         seq_printf(m, " find-mask forwards checks:     %11u\n",
 291                 debug_atomic_read(&nr_find_usage_forwards_checks));
 292         seq_printf(m, " find-mask forwards recursions: %11u\n",
 293                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 294         seq_printf(m, " find-mask backwards checks:    %11u\n",
 295                 debug_atomic_read(&nr_find_usage_backwards_checks));
 296         seq_printf(m, " find-mask backwards recursions:%11u\n",
 297                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 298
 299         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 300         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 301         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 302         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 303         seq_printf(m, " softirq on events:             %11u\n", si1);
 304         seq_printf(m, " softirq off events:            %11u\n", si2);
 305         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 306         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 307 #endif
 308 }
 309
 310 static int lockdep_stats_show(struct seq_file *m, void *v)
 311 {
 312         struct lock_class *class;
 313         unsigned long nr_unused = 0, nr_uncategorized = 0,
 314                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 315                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 316                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 317                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 318                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 319                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 320                       sum_forward_deps = 0, factor = 0;
 321
 322         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 323
 324                 if (class->usage_mask == 0)
 325                         nr_unused++;
 326                 if (class->usage_mask == LOCKF_USED)
 327                         nr_uncategorized++;
 328                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 329                         nr_irq_safe++;
 330                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
 331                         nr_irq_unsafe++;
 332                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 333                         nr_softirq_safe++;
 334                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
 335                         nr_softirq_unsafe++;
 336                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 337                         nr_hardirq_safe++;
 338                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
 339                         nr_hardirq_unsafe++;
 340                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 341                         nr_irq_read_safe++;
 342                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
 343                         nr_irq_read_unsafe++;
 344                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 345                         nr_softirq_read_safe++;
 346                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
 347                         nr_softirq_read_unsafe++;
 348                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 349                         nr_hardirq_read_safe++;
 350                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
 351                         nr_hardirq_read_unsafe++;
 352
 353                 sum_forward_deps += count_forward_deps(class);
 354         }
 355 #ifdef CONFIG_DEBUG_LOCKDEP
 356         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 357 #endif
 358         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 359                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 360         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 361                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 362         seq_printf(m, " indirect dependencies:         %11lu\n",
 363                         sum_forward_deps);
 364
 365         /*
 366          * Total number of dependencies:
 367          *
 368          * All irq-safe locks may nest inside irq-unsafe locks,
 369          * plus all the other known dependencies:
 370          */
 371         seq_printf(m, " all direct dependencies:       %11lu\n",
 372                         nr_irq_unsafe * nr_irq_safe +
 373                         nr_hardirq_unsafe * nr_hardirq_safe +
 374                         nr_list_entries);
 375
 376         /*
 377          * Estimated factor between direct and indirect
 378          * dependencies:
 379          */
 380         if (nr_list_entries)
 381                 factor = sum_forward_deps / nr_list_entries;
 382
 383 #ifdef CONFIG_PROVE_LOCKING
 384         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 385                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 386         seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
 387                         nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
 388 #endif
 389
 390 #ifdef CONFIG_TRACE_IRQFLAGS
 391         seq_printf(m, " in-hardirq chains:             %11u\n",
 392                         nr_hardirq_chains);
 393         seq_printf(m, " in-softirq chains:             %11u\n",
 394                         nr_softirq_chains);
 395 #endif
 396         seq_printf(m, " in-process chains:             %11u\n",
 397                         nr_process_chains);
 398         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 399                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 400         seq_printf(m, " combined max dependencies:     %11u\n",
 401                         (nr_hardirq_chains + 1) *
 402                         (nr_softirq_chains + 1) *
 403                         (nr_process_chains + 1)
 404         );
 405         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 406                         nr_hardirq_safe);
 407         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 408                         nr_hardirq_unsafe);
 409         seq_printf(m, " softirq-safe locks:            %11lu\n",
 410                         nr_softirq_safe);
 411         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 412                         nr_softirq_unsafe);
 413         seq_printf(m, " irq-safe locks:                %11lu\n",
 414                         nr_irq_safe);
 415         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 416                         nr_irq_unsafe);
 417
 418         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 419                         nr_hardirq_read_safe);
 420         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 421                         nr_hardirq_read_unsafe);
 422         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 423                         nr_softirq_read_safe);
 424         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 425                         nr_softirq_read_unsafe);
 426         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 427                         nr_irq_read_safe);
 428         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 429                         nr_irq_read_unsafe);
 430
 431         seq_printf(m, " uncategorized locks:           %11lu\n",
 432                         nr_uncategorized);
 433         seq_printf(m, " unused locks:                  %11lu\n",
 434                         nr_unused);
 435         seq_printf(m, " max locking depth:             %11u\n",
 436                         max_lockdep_depth);
 437         seq_printf(m, " max recursion depth:           %11u\n",
 438                         max_recursion_depth);
 439         lockdep_stats_debug_show(m);
 440         seq_printf(m, " debug_locks:                   %11u\n",
 441                         debug_locks);
 442
 443         return 0;
 444 }
 445
 446 static int lockdep_stats_open(struct inode *inode, struct file *file)
 447 {
 448         return single_open(file, lockdep_stats_show, NULL);
 449 }
 450
 451 static const struct file_operations proc_lockdep_stats_operations = {
 452         .open           = lockdep_stats_open,
 453         .read           = seq_read,
 454         .llseek         = seq_lseek,
 455         .release        = single_release,
 456 };
 457
 458 #ifdef CONFIG_LOCK_STAT
 459
 460 struct lock_stat_data {
 461         struct lock_class *class;
 462         struct lock_class_stats stats;
 463 };
 464
 465 struct lock_stat_seq {
 466         struct lock_stat_data *iter;
 467         struct lock_stat_data *iter_end;
 468         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 469 };
 470
 471 /*
 472  * sort on absolute number of contentions
 473  */
 474 static int lock_stat_cmp(const void *l, const void *r)
 475 {
 476         const struct lock_stat_data *dl = l, *dr = r;
 477         unsigned long nl, nr;
 478
 479         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 480         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 481
 482         return nr - nl;
 483 }
 484
 485 static void seq_line(struct seq_file *m, char c, int offset, int length)
 486 {
 487         int i;
 488
 489         for (i = 0; i < offset; i++)
 490                 seq_puts(m, " ");
 491         for (i = 0; i < length; i++)
 492                 seq_printf(m, "%c", c);
 493         seq_puts(m, "\n");
 494 }
 495
 496 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 497 {
 498         unsigned long rem;
 499
 500         rem = do_div(nr, 1000); /* XXX: do_div_signed */
 501         snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
 502 }
 503
 504 static void seq_time(struct seq_file *m, s64 time)
 505 {
 506         char num[15];
 507
 508         snprint_time(num, sizeof(num), time);
 509         seq_printf(m, " %14s", num);
 510 }
 511
 512 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 513 {
 514         seq_printf(m, "%14lu", lt->nr);
 515         seq_time(m, lt->min);
 516         seq_time(m, lt->max);
 517         seq_time(m, lt->total);
 518 }
 519
 520 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 521 {
 522         char name[39];
 523         struct lock_class *class;
 524         struct lock_class_stats *stats;
 525         int i, namelen;
 526
 527         class = data->class;
 528         stats = &data->stats;
 529
 530         namelen = 38;
 531         if (class->name_version > 1)
 532                 namelen -= 2; /* XXX truncates versions > 9 */
 533         if (class->subclass)
 534                 namelen -= 2;
 535
 536         if (!class->name) {
 537                 char str[KSYM_NAME_LEN];
 538                 const char *key_name;
 539
 540                 key_name = __get_key_name(class->key, str);
 541                 snprintf(name, namelen, "%s", key_name);
 542         } else {
 543                 snprintf(name, namelen, "%s", class->name);
 544         }
 545         namelen = strlen(name);
 546         if (class->name_version > 1) {
 547                 snprintf(name+namelen, 3, "#%d", class->name_version);
 548                 namelen += 2;
 549         }
 550         if (class->subclass) {
 551                 snprintf(name+namelen, 3, "/%d", class->subclass);
 552                 namelen += 2;
 553         }
 554
 555         if (stats->write_holdtime.nr) {
 556                 if (stats->read_holdtime.nr)
 557                         seq_printf(m, "%38s-W:", name);
 558                 else
 559                         seq_printf(m, "%40s:", name);
 560
 561                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
 562                 seq_lock_time(m, &stats->write_waittime);
 563                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
 564                 seq_lock_time(m, &stats->write_holdtime);
 565                 seq_puts(m, "\n");
 566         }
 567
 568         if (stats->read_holdtime.nr) {
 569                 seq_printf(m, "%38s-R:", name);
 570                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
 571                 seq_lock_time(m, &stats->read_waittime);
 572                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
 573                 seq_lock_time(m, &stats->read_holdtime);
 574                 seq_puts(m, "\n");
 575         }
 576
 577         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 578                 return;
 579
 580         if (stats->read_holdtime.nr)
 581                 namelen += 2;
 582
 583         for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
 584                 char sym[KSYM_SYMBOL_LEN];
 585                 char ip[32];
 586
 587                 if (class->contention_point[i] == 0)
 588                         break;
 589
 590                 if (!i)
 591                         seq_line(m, '-', 40-namelen, namelen);
 592
 593                 sprint_symbol(sym, class->contention_point[i]);
 594                 snprintf(ip, sizeof(ip), "[<%p>]",
 595                                 (void *)class->contention_point[i]);
 596                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 597                                 stats->contention_point[i],
 598                                 ip, sym);
 599         }
 600         if (i) {
 601                 seq_puts(m, "\n");
 602                 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
 603                 seq_puts(m, "\n");
 604         }
 605 }
 606
 607 static void seq_header(struct seq_file *m)
 608 {
 609         seq_printf(m, "lock_stat version 0.2\n");
 610         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 611         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
 612                         "%14s %14s\n",
 613                         "class name",
 614                         "con-bounces",
 615                         "contentions",
 616                         "waittime-min",
 617                         "waittime-max",
 618                         "waittime-total",
 619                         "acq-bounces",
 620                         "acquisitions",
 621                         "holdtime-min",
 622                         "holdtime-max",
 623                         "holdtime-total");
 624         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
 625         seq_printf(m, "\n");
 626 }
 627
 628 static void *ls_start(struct seq_file *m, loff_t *pos)
 629 {
 630         struct lock_stat_seq *data = m->private;
 631
 632         if (*pos == 0)
 633                 return SEQ_START_TOKEN;
 634
 635         data->iter = data->stats + *pos;
 636         if (data->iter >= data->iter_end)
 637                 data->iter = NULL;
 638
 639         return data->iter;
 640 }
 641
 642 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 643 {
 644         struct lock_stat_seq *data = m->private;
 645
 646         (*pos)++;
 647
 648         if (v == SEQ_START_TOKEN)
 649                 data->iter = data->stats;
 650         else {
 651                 data->iter = v;
 652                 data->iter++;
 653         }
 654
 655         if (data->iter == data->iter_end)
 656                 data->iter = NULL;
 657
 658         return data->iter;
 659 }
 660
 661 static void ls_stop(struct seq_file *m, void *v)
 662 {
 663 }
 664
 665 static int ls_show(struct seq_file *m, void *v)
 666 {
 667         if (v == SEQ_START_TOKEN)
 668                 seq_header(m);
 669         else
 670                 seq_stats(m, v);
 671
 672         return 0;
 673 }
 674
 675 static struct seq_operations lockstat_ops = {
 676         .start  = ls_start,
 677         .next   = ls_next,
 678         .stop   = ls_stop,
 679         .show   = ls_show,
 680 };
 681
 682 static int lock_stat_open(struct inode *inode, struct file *file)
 683 {
 684         int res;
 685         struct lock_class *class;
 686         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
 687
 688         if (!data)
 689                 return -ENOMEM;
 690
 691         res = seq_open(file, &lockstat_ops);
 692         if (!res) {
 693                 struct lock_stat_data *iter = data->stats;
 694                 struct seq_file *m = file->private_data;
 695
 696                 data->iter = iter;
 697                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
 698                         iter->class = class;
 699                         iter->stats = lock_stats(class);
 700                         iter++;
 701                 }
 702                 data->iter_end = iter;
 703
 704                 sort(data->stats, data->iter_end - data->iter,
 705                                 sizeof(struct lock_stat_data),
 706                                 lock_stat_cmp, NULL);
 707
 708                 m->private = data;
 709         } else
 710                 vfree(data);
 711
 712         return res;
 713 }
 714
 715 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
 716                                size_t count, loff_t *ppos)
 717 {
 718         struct lock_class *class;
 719         char c;
 720
 721         if (count) {
 722                 if (get_user(c, buf))
 723                         return -EFAULT;
 724
 725                 if (c != '0')
 726                         return count;
 727
 728                 list_for_each_entry(class, &all_lock_classes, lock_entry)
 729                         clear_lock_stats(class);
 730         }
 731         return count;
 732 }
 733
 734 static int lock_stat_release(struct inode *inode, struct file *file)
 735 {
 736         struct seq_file *seq = file->private_data;
 737
 738         vfree(seq->private);
 739         seq->private = NULL;
 740         return seq_release(inode, file);
 741 }
 742
 743 static const struct file_operations proc_lock_stat_operations = {
 744         .open           = lock_stat_open,
 745         .write          = lock_stat_write,
 746         .read           = seq_read,
 747         .llseek         = seq_lseek,
 748         .release        = lock_stat_release,
 749 };
 750 #endif /* CONFIG_LOCK_STAT */
 751
 752 static int __init lockdep_proc_init(void)
 753 {
 754         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
 755 #ifdef CONFIG_PROVE_LOCKING
 756         proc_create("lockdep_chains", S_IRUSR, NULL,
 757                     &proc_lockdep_chains_operations);
 758 #endif
 759         proc_create("lockdep_stats", S_IRUSR, NULL,
 760                     &proc_lockdep_stats_operations);
 761
 762 #ifdef CONFIG_LOCK_STAT
 763         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
 764 #endif
 765
 766         return 0;
 767 }
 768
 769 __initcall(lockdep_proc_init);
 770