linux/kernel/lockdep_proc.c
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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
  26static 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
  47static 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
  62static void l_stop(struct seq_file *m, void *v)
  63{
  64}
  65
  66static 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
  83static 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
 122static const struct seq_operations lockdep_ops = {
 123        .start  = l_start,
 124        .next   = l_next,
 125        .stop   = l_stop,
 126        .show   = l_show,
 127};
 128
 129static 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
 144static 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
 152static 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
 172static 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
 183static void lc_stop(struct seq_file *m, void *v)
 184{
 185}
 186
 187static 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
 214static 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
 221static 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
 235static 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
 243static 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
 283static 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        lockdep_stats_debug_show(m);
 415        seq_printf(m, " debug_locks:                   %11u\n",
 416                        debug_locks);
 417
 418        return 0;
 419}
 420
 421static int lockdep_stats_open(struct inode *inode, struct file *file)
 422{
 423        return single_open(file, lockdep_stats_show, NULL);
 424}
 425
 426static const struct file_operations proc_lockdep_stats_operations = {
 427        .open           = lockdep_stats_open,
 428        .read           = seq_read,
 429        .llseek         = seq_lseek,
 430        .release        = single_release,
 431};
 432
 433#ifdef CONFIG_LOCK_STAT
 434
 435struct lock_stat_data {
 436        struct lock_class *class;
 437        struct lock_class_stats stats;
 438};
 439
 440struct lock_stat_seq {
 441        struct lock_stat_data *iter;
 442        struct lock_stat_data *iter_end;
 443        struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 444};
 445
 446/*
 447 * sort on absolute number of contentions
 448 */
 449static int lock_stat_cmp(const void *l, const void *r)
 450{
 451        const struct lock_stat_data *dl = l, *dr = r;
 452        unsigned long nl, nr;
 453
 454        nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 455        nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 456
 457        return nr - nl;
 458}
 459
 460static void seq_line(struct seq_file *m, char c, int offset, int length)
 461{
 462        int i;
 463
 464        for (i = 0; i < offset; i++)
 465                seq_puts(m, " ");
 466        for (i = 0; i < length; i++)
 467                seq_printf(m, "%c", c);
 468        seq_puts(m, "\n");
 469}
 470
 471static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 472{
 473        s64 div;
 474        s32 rem;
 475
 476        nr += 5; /* for display rounding */
 477        div = div_s64_rem(nr, 1000, &rem);
 478        snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
 479}
 480
 481static void seq_time(struct seq_file *m, s64 time)
 482{
 483        char num[15];
 484
 485        snprint_time(num, sizeof(num), time);
 486        seq_printf(m, " %14s", num);
 487}
 488
 489static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 490{
 491        seq_printf(m, "%14lu", lt->nr);
 492        seq_time(m, lt->min);
 493        seq_time(m, lt->max);
 494        seq_time(m, lt->total);
 495}
 496
 497static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 498{
 499        char name[39];
 500        struct lock_class *class;
 501        struct lock_class_stats *stats;
 502        int i, namelen;
 503
 504        class = data->class;
 505        stats = &data->stats;
 506
 507        namelen = 38;
 508        if (class->name_version > 1)
 509                namelen -= 2; /* XXX truncates versions > 9 */
 510        if (class->subclass)
 511                namelen -= 2;
 512
 513        if (!class->name) {
 514                char str[KSYM_NAME_LEN];
 515                const char *key_name;
 516
 517                key_name = __get_key_name(class->key, str);
 518                snprintf(name, namelen, "%s", key_name);
 519        } else {
 520                snprintf(name, namelen, "%s", class->name);
 521        }
 522        namelen = strlen(name);
 523        if (class->name_version > 1) {
 524                snprintf(name+namelen, 3, "#%d", class->name_version);
 525                namelen += 2;
 526        }
 527        if (class->subclass) {
 528                snprintf(name+namelen, 3, "/%d", class->subclass);
 529                namelen += 2;
 530        }
 531
 532        if (stats->write_holdtime.nr) {
 533                if (stats->read_holdtime.nr)
 534                        seq_printf(m, "%38s-W:", name);
 535                else
 536                        seq_printf(m, "%40s:", name);
 537
 538                seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
 539                seq_lock_time(m, &stats->write_waittime);
 540                seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
 541                seq_lock_time(m, &stats->write_holdtime);
 542                seq_puts(m, "\n");
 543        }
 544
 545        if (stats->read_holdtime.nr) {
 546                seq_printf(m, "%38s-R:", name);
 547                seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
 548                seq_lock_time(m, &stats->read_waittime);
 549                seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
 550                seq_lock_time(m, &stats->read_holdtime);
 551                seq_puts(m, "\n");
 552        }
 553
 554        if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 555                return;
 556
 557        if (stats->read_holdtime.nr)
 558                namelen += 2;
 559
 560        for (i = 0; i < LOCKSTAT_POINTS; i++) {
 561                char sym[KSYM_SYMBOL_LEN];
 562                char ip[32];
 563
 564                if (class->contention_point[i] == 0)
 565                        break;
 566
 567                if (!i)
 568                        seq_line(m, '-', 40-namelen, namelen);
 569
 570                sprint_symbol(sym, class->contention_point[i]);
 571                snprintf(ip, sizeof(ip), "[<%p>]",
 572                                (void *)class->contention_point[i]);
 573                seq_printf(m, "%40s %14lu %29s %s\n", name,
 574                                stats->contention_point[i],
 575                                ip, sym);
 576        }
 577        for (i = 0; i < LOCKSTAT_POINTS; i++) {
 578                char sym[KSYM_SYMBOL_LEN];
 579                char ip[32];
 580
 581                if (class->contending_point[i] == 0)
 582                        break;
 583
 584                if (!i)
 585                        seq_line(m, '-', 40-namelen, namelen);
 586
 587                sprint_symbol(sym, class->contending_point[i]);
 588                snprintf(ip, sizeof(ip), "[<%p>]",
 589                                (void *)class->contending_point[i]);
 590                seq_printf(m, "%40s %14lu %29s %s\n", name,
 591                                stats->contending_point[i],
 592                                ip, sym);
 593        }
 594        if (i) {
 595                seq_puts(m, "\n");
 596                seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
 597                seq_puts(m, "\n");
 598        }
 599}
 600
 601static void seq_header(struct seq_file *m)
 602{
 603        seq_printf(m, "lock_stat version 0.3\n");
 604
 605        if (unlikely(!debug_locks))
 606                seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
 607
 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
 626static 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
 640static 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
 659static void ls_stop(struct seq_file *m, void *v)
 660{
 661}
 662
 663static 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
 673static struct seq_operations lockstat_ops = {
 674        .start  = ls_start,
 675        .next   = ls_next,
 676        .stop   = ls_stop,
 677        .show   = ls_show,
 678};
 679
 680static 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
 713static 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
 732static 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
 741static 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
 750static int __init lockdep_proc_init(void)
 751{
 752        proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
 753#ifdef CONFIG_PROVE_LOCKING
 754        proc_create("lockdep_chains", S_IRUSR, NULL,
 755                    &proc_lockdep_chains_operations);
 756#endif
 757        proc_create("lockdep_stats", S_IRUSR, NULL,
 758                    &proc_lockdep_stats_operations);
 759
 760#ifdef CONFIG_LOCK_STAT
 761        proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
 762#endif
 763
 764        return 0;
 765}
 766
 767__initcall(lockdep_proc_init);
 768
 769