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