Merge commit 'linus/master' into merge-linus
[linux-2.6.git] / 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 void print_name(struct seq_file *m, struct lock_class *class)
67 {
68         char str[128];
69         const char *name = class->name;
70
71         if (!name) {
72                 name = __get_key_name(class->key, str);
73                 seq_printf(m, "%s", name);
74         } else{
75                 seq_printf(m, "%s", name);
76                 if (class->name_version > 1)
77                         seq_printf(m, "#%d", class->name_version);
78                 if (class->subclass)
79                         seq_printf(m, "/%d", class->subclass);
80         }
81 }
82
83 static int l_show(struct seq_file *m, void *v)
84 {
85         struct lock_class *class = v;
86         struct lock_list *entry;
87         char c1, c2, c3, c4;
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, &c1, &c2, &c3, &c4);
104         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
105
106         seq_printf(m, ": ");
107         print_name(m, class);
108         seq_puts(m, "\n");
109
110         list_for_each_entry(entry, &class->locks_after, entry) {
111                 if (entry->distance == 1) {
112                         seq_printf(m, " -> [%p] ", entry->class->key);
113                         print_name(m, entry->class);
114                         seq_puts(m, "\n");
115                 }
116         }
117         seq_puts(m, "\n");
118
119         return 0;
120 }
121
122 static const struct seq_operations lockdep_ops = {
123         .start  = l_start,
124         .next   = l_next,
125         .stop   = l_stop,
126         .show   = l_show,
127 };
128
129 static int lockdep_open(struct inode *inode, struct file *file)
130 {
131         int res = seq_open(file, &lockdep_ops);
132         if (!res) {
133                 struct seq_file *m = file->private_data;
134
135                 if (!list_empty(&all_lock_classes))
136                         m->private = list_entry(all_lock_classes.next,
137                                         struct lock_class, lock_entry);
138                 else
139                         m->private = NULL;
140         }
141         return res;
142 }
143
144 static const struct file_operations proc_lockdep_operations = {
145         .open           = lockdep_open,
146         .read           = seq_read,
147         .llseek         = seq_lseek,
148         .release        = seq_release,
149 };
150
151 #ifdef CONFIG_PROVE_LOCKING
152 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
153 {
154         struct lock_chain *chain;
155
156         (*pos)++;
157
158         if (v == SEQ_START_TOKEN)
159                 chain = m->private;
160         else {
161                 chain = v;
162
163                 if (*pos < nr_lock_chains)
164                         chain = lock_chains + *pos;
165                 else
166                         chain = NULL;
167         }
168
169         return chain;
170 }
171
172 static void *lc_start(struct seq_file *m, loff_t *pos)
173 {
174         if (*pos == 0)
175                 return SEQ_START_TOKEN;
176
177         if (*pos < nr_lock_chains)
178                 return lock_chains + *pos;
179
180         return NULL;
181 }
182
183 static void lc_stop(struct seq_file *m, void *v)
184 {
185 }
186
187 static int lc_show(struct seq_file *m, void *v)
188 {
189         struct lock_chain *chain = v;
190         struct lock_class *class;
191         int i;
192
193         if (v == SEQ_START_TOKEN) {
194                 seq_printf(m, "all lock chains:\n");
195                 return 0;
196         }
197
198         seq_printf(m, "irq_context: %d\n", chain->irq_context);
199
200         for (i = 0; i < chain->depth; i++) {
201                 class = lock_chain_get_class(chain, i);
202                 if (!class->key)
203                         continue;
204
205                 seq_printf(m, "[%p] ", class->key);
206                 print_name(m, class);
207                 seq_puts(m, "\n");
208         }
209         seq_puts(m, "\n");
210
211         return 0;
212 }
213
214 static const struct seq_operations lockdep_chains_ops = {
215         .start  = lc_start,
216         .next   = lc_next,
217         .stop   = lc_stop,
218         .show   = lc_show,
219 };
220
221 static int lockdep_chains_open(struct inode *inode, struct file *file)
222 {
223         int res = seq_open(file, &lockdep_chains_ops);
224         if (!res) {
225                 struct seq_file *m = file->private_data;
226
227                 if (nr_lock_chains)
228                         m->private = lock_chains;
229                 else
230                         m->private = NULL;
231         }
232         return res;
233 }
234
235 static const struct file_operations proc_lockdep_chains_operations = {
236         .open           = lockdep_chains_open,
237         .read           = seq_read,
238         .llseek         = seq_lseek,
239         .release        = seq_release,
240 };
241 #endif /* CONFIG_PROVE_LOCKING */
242
243 static void lockdep_stats_debug_show(struct seq_file *m)
244 {
245 #ifdef CONFIG_DEBUG_LOCKDEP
246         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
247                      hi2 = debug_atomic_read(&hardirqs_off_events),
248                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
249                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
250                      si1 = debug_atomic_read(&softirqs_on_events),
251                      si2 = debug_atomic_read(&softirqs_off_events),
252                      sr1 = debug_atomic_read(&redundant_softirqs_on),
253                      sr2 = debug_atomic_read(&redundant_softirqs_off);
254
255         seq_printf(m, " chain lookup misses:           %11u\n",
256                 debug_atomic_read(&chain_lookup_misses));
257         seq_printf(m, " chain lookup hits:             %11u\n",
258                 debug_atomic_read(&chain_lookup_hits));
259         seq_printf(m, " cyclic checks:                 %11u\n",
260                 debug_atomic_read(&nr_cyclic_checks));
261         seq_printf(m, " cyclic-check recursions:       %11u\n",
262                 debug_atomic_read(&nr_cyclic_check_recursions));
263         seq_printf(m, " find-mask forwards checks:     %11u\n",
264                 debug_atomic_read(&nr_find_usage_forwards_checks));
265         seq_printf(m, " find-mask forwards recursions: %11u\n",
266                 debug_atomic_read(&nr_find_usage_forwards_recursions));
267         seq_printf(m, " find-mask backwards checks:    %11u\n",
268                 debug_atomic_read(&nr_find_usage_backwards_checks));
269         seq_printf(m, " find-mask backwards recursions:%11u\n",
270                 debug_atomic_read(&nr_find_usage_backwards_recursions));
271
272         seq_printf(m, " hardirq on events:             %11u\n", hi1);
273         seq_printf(m, " hardirq off events:            %11u\n", hi2);
274         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
275         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
276         seq_printf(m, " softirq on events:             %11u\n", si1);
277         seq_printf(m, " softirq off events:            %11u\n", si2);
278         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
279         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
280 #endif
281 }
282
283 static int lockdep_stats_show(struct seq_file *m, void *v)
284 {
285         struct lock_class *class;
286         unsigned long nr_unused = 0, nr_uncategorized = 0,
287                       nr_irq_safe = 0, nr_irq_unsafe = 0,
288                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
289                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
290                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
291                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
292                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
293                       sum_forward_deps = 0, factor = 0;
294
295         list_for_each_entry(class, &all_lock_classes, lock_entry) {
296
297                 if (class->usage_mask == 0)
298                         nr_unused++;
299                 if (class->usage_mask == LOCKF_USED)
300                         nr_uncategorized++;
301                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
302                         nr_irq_safe++;
303                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
304                         nr_irq_unsafe++;
305                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
306                         nr_softirq_safe++;
307                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
308                         nr_softirq_unsafe++;
309                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
310                         nr_hardirq_safe++;
311                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
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_IRQS_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_SOFTIRQS_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_HARDIRQS_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
421 static int lockdep_stats_open(struct inode *inode, struct file *file)
422 {
423         return single_open(file, lockdep_stats_show, NULL);
424 }
425
426 static 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
435 struct lock_stat_data {
436         struct lock_class *class;
437         struct lock_class_stats stats;
438 };
439
440 struct 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  */
449 static 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
460 static 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
471 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
472 {
473         unsigned long rem;
474
475         nr += 5; /* for display rounding */
476         rem = do_div(nr, 1000); /* XXX: do_div_signed */
477         snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, (int)rem/10);
478 }
479
480 static void seq_time(struct seq_file *m, s64 time)
481 {
482         char num[15];
483
484         snprint_time(num, sizeof(num), time);
485         seq_printf(m, " %14s", num);
486 }
487
488 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
489 {
490         seq_printf(m, "%14lu", lt->nr);
491         seq_time(m, lt->min);
492         seq_time(m, lt->max);
493         seq_time(m, lt->total);
494 }
495
496 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
497 {
498         char name[39];
499         struct lock_class *class;
500         struct lock_class_stats *stats;
501         int i, namelen;
502
503         class = data->class;
504         stats = &data->stats;
505
506         namelen = 38;
507         if (class->name_version > 1)
508                 namelen -= 2; /* XXX truncates versions > 9 */
509         if (class->subclass)
510                 namelen -= 2;
511
512         if (!class->name) {
513                 char str[KSYM_NAME_LEN];
514                 const char *key_name;
515
516                 key_name = __get_key_name(class->key, str);
517                 snprintf(name, namelen, "%s", key_name);
518         } else {
519                 snprintf(name, namelen, "%s", class->name);
520         }
521         namelen = strlen(name);
522         if (class->name_version > 1) {
523                 snprintf(name+namelen, 3, "#%d", class->name_version);
524                 namelen += 2;
525         }
526         if (class->subclass) {
527                 snprintf(name+namelen, 3, "/%d", class->subclass);
528                 namelen += 2;
529         }
530
531         if (stats->write_holdtime.nr) {
532                 if (stats->read_holdtime.nr)
533                         seq_printf(m, "%38s-W:", name);
534                 else
535                         seq_printf(m, "%40s:", name);
536
537                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
538                 seq_lock_time(m, &stats->write_waittime);
539                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
540                 seq_lock_time(m, &stats->write_holdtime);
541                 seq_puts(m, "\n");
542         }
543
544         if (stats->read_holdtime.nr) {
545                 seq_printf(m, "%38s-R:", name);
546                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
547                 seq_lock_time(m, &stats->read_waittime);
548                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
549                 seq_lock_time(m, &stats->read_holdtime);
550                 seq_puts(m, "\n");
551         }
552
553         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
554                 return;
555
556         if (stats->read_holdtime.nr)
557                 namelen += 2;
558
559         for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
560                 char sym[KSYM_SYMBOL_LEN];
561                 char ip[32];
562
563                 if (class->contention_point[i] == 0)
564                         break;
565
566                 if (!i)
567                         seq_line(m, '-', 40-namelen, namelen);
568
569                 sprint_symbol(sym, class->contention_point[i]);
570                 snprintf(ip, sizeof(ip), "[<%p>]",
571                                 (void *)class->contention_point[i]);
572                 seq_printf(m, "%40s %14lu %29s %s\n", name,
573                                 stats->contention_point[i],
574                                 ip, sym);
575         }
576         if (i) {
577                 seq_puts(m, "\n");
578                 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
579                 seq_puts(m, "\n");
580         }
581 }
582
583 static void seq_header(struct seq_file *m)
584 {
585         seq_printf(m, "lock_stat version 0.2\n");
586         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
587         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
588                         "%14s %14s\n",
589                         "class name",
590                         "con-bounces",
591                         "contentions",
592                         "waittime-min",
593                         "waittime-max",
594                         "waittime-total",
595                         "acq-bounces",
596                         "acquisitions",
597                         "holdtime-min",
598                         "holdtime-max",
599                         "holdtime-total");
600         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
601         seq_printf(m, "\n");
602 }
603
604 static void *ls_start(struct seq_file *m, loff_t *pos)
605 {
606         struct lock_stat_seq *data = m->private;
607
608         if (*pos == 0)
609                 return SEQ_START_TOKEN;
610
611         data->iter = data->stats + *pos;
612         if (data->iter >= data->iter_end)
613                 data->iter = NULL;
614
615         return data->iter;
616 }
617
618 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
619 {
620         struct lock_stat_seq *data = m->private;
621
622         (*pos)++;
623
624         if (v == SEQ_START_TOKEN)
625                 data->iter = data->stats;
626         else {
627                 data->iter = v;
628                 data->iter++;
629         }
630
631         if (data->iter == data->iter_end)
632                 data->iter = NULL;
633
634         return data->iter;
635 }
636
637 static void ls_stop(struct seq_file *m, void *v)
638 {
639 }
640
641 static int ls_show(struct seq_file *m, void *v)
642 {
643         if (v == SEQ_START_TOKEN)
644                 seq_header(m);
645         else
646                 seq_stats(m, v);
647
648         return 0;
649 }
650
651 static struct seq_operations lockstat_ops = {
652         .start  = ls_start,
653         .next   = ls_next,
654         .stop   = ls_stop,
655         .show   = ls_show,
656 };
657
658 static int lock_stat_open(struct inode *inode, struct file *file)
659 {
660         int res;
661         struct lock_class *class;
662         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
663
664         if (!data)
665                 return -ENOMEM;
666
667         res = seq_open(file, &lockstat_ops);
668         if (!res) {
669                 struct lock_stat_data *iter = data->stats;
670                 struct seq_file *m = file->private_data;
671
672                 data->iter = iter;
673                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
674                         iter->class = class;
675                         iter->stats = lock_stats(class);
676                         iter++;
677                 }
678                 data->iter_end = iter;
679
680                 sort(data->stats, data->iter_end - data->iter,
681                                 sizeof(struct lock_stat_data),
682                                 lock_stat_cmp, NULL);
683
684                 m->private = data;
685         } else
686                 vfree(data);
687
688         return res;
689 }
690
691 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
692                                size_t count, loff_t *ppos)
693 {
694         struct lock_class *class;
695         char c;
696
697         if (count) {
698                 if (get_user(c, buf))
699                         return -EFAULT;
700
701                 if (c != '0')
702                         return count;
703
704                 list_for_each_entry(class, &all_lock_classes, lock_entry)
705                         clear_lock_stats(class);
706         }
707         return count;
708 }
709
710 static int lock_stat_release(struct inode *inode, struct file *file)
711 {
712         struct seq_file *seq = file->private_data;
713
714         vfree(seq->private);
715         seq->private = NULL;
716         return seq_release(inode, file);
717 }
718
719 static const struct file_operations proc_lock_stat_operations = {
720         .open           = lock_stat_open,
721         .write          = lock_stat_write,
722         .read           = seq_read,
723         .llseek         = seq_lseek,
724         .release        = lock_stat_release,
725 };
726 #endif /* CONFIG_LOCK_STAT */
727
728 static int __init lockdep_proc_init(void)
729 {
730         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
731 #ifdef CONFIG_PROVE_LOCKING
732         proc_create("lockdep_chains", S_IRUSR, NULL,
733                     &proc_lockdep_chains_operations);
734 #endif
735         proc_create("lockdep_stats", S_IRUSR, NULL,
736                     &proc_lockdep_stats_operations);
737
738 #ifdef CONFIG_LOCK_STAT
739         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
740 #endif
741
742         return 0;
743 }
744
745 __initcall(lockdep_proc_init);
746