fba81f16e3462a99466a3fda597f29631e0e1a9f
[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 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
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_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 #ifdef CONFIG_PROVE_LOCKING
415         seq_printf(m, " max bfs queue depth:           %11u\n",
416                         max_bfs_queue_depth);
417 #endif
418         lockdep_stats_debug_show(m);
419         seq_printf(m, " debug_locks:                   %11u\n",
420                         debug_locks);
421
422         return 0;
423 }
424
425 static int lockdep_stats_open(struct inode *inode, struct file *file)
426 {
427         return single_open(file, lockdep_stats_show, NULL);
428 }
429
430 static const struct file_operations proc_lockdep_stats_operations = {
431         .open           = lockdep_stats_open,
432         .read           = seq_read,
433         .llseek         = seq_lseek,
434         .release        = single_release,
435 };
436
437 #ifdef CONFIG_LOCK_STAT
438
439 struct lock_stat_data {
440         struct lock_class *class;
441         struct lock_class_stats stats;
442 };
443
444 struct lock_stat_seq {
445         struct lock_stat_data *iter;
446         struct lock_stat_data *iter_end;
447         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
448 };
449
450 /*
451  * sort on absolute number of contentions
452  */
453 static int lock_stat_cmp(const void *l, const void *r)
454 {
455         const struct lock_stat_data *dl = l, *dr = r;
456         unsigned long nl, nr;
457
458         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
459         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
460
461         return nr - nl;
462 }
463
464 static void seq_line(struct seq_file *m, char c, int offset, int length)
465 {
466         int i;
467
468         for (i = 0; i < offset; i++)
469                 seq_puts(m, " ");
470         for (i = 0; i < length; i++)
471                 seq_printf(m, "%c", c);
472         seq_puts(m, "\n");
473 }
474
475 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
476 {
477         s64 div;
478         s32 rem;
479
480         nr += 5; /* for display rounding */
481         div = div_s64_rem(nr, 1000, &rem);
482         snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
483 }
484
485 static void seq_time(struct seq_file *m, s64 time)
486 {
487         char num[15];
488
489         snprint_time(num, sizeof(num), time);
490         seq_printf(m, " %14s", num);
491 }
492
493 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
494 {
495         seq_printf(m, "%14lu", lt->nr);
496         seq_time(m, lt->min);
497         seq_time(m, lt->max);
498         seq_time(m, lt->total);
499 }
500
501 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
502 {
503         char name[39];
504         struct lock_class *class;
505         struct lock_class_stats *stats;
506         int i, namelen;
507
508         class = data->class;
509         stats = &data->stats;
510
511         namelen = 38;
512         if (class->name_version > 1)
513                 namelen -= 2; /* XXX truncates versions > 9 */
514         if (class->subclass)
515                 namelen -= 2;
516
517         if (!class->name) {
518                 char str[KSYM_NAME_LEN];
519                 const char *key_name;
520
521                 key_name = __get_key_name(class->key, str);
522                 snprintf(name, namelen, "%s", key_name);
523         } else {
524                 snprintf(name, namelen, "%s", class->name);
525         }
526         namelen = strlen(name);
527         if (class->name_version > 1) {
528                 snprintf(name+namelen, 3, "#%d", class->name_version);
529                 namelen += 2;
530         }
531         if (class->subclass) {
532                 snprintf(name+namelen, 3, "/%d", class->subclass);
533                 namelen += 2;
534         }
535
536         if (stats->write_holdtime.nr) {
537                 if (stats->read_holdtime.nr)
538                         seq_printf(m, "%38s-W:", name);
539                 else
540                         seq_printf(m, "%40s:", name);
541
542                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
543                 seq_lock_time(m, &stats->write_waittime);
544                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
545                 seq_lock_time(m, &stats->write_holdtime);
546                 seq_puts(m, "\n");
547         }
548
549         if (stats->read_holdtime.nr) {
550                 seq_printf(m, "%38s-R:", name);
551                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
552                 seq_lock_time(m, &stats->read_waittime);
553                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
554                 seq_lock_time(m, &stats->read_holdtime);
555                 seq_puts(m, "\n");
556         }
557
558         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
559                 return;
560
561         if (stats->read_holdtime.nr)
562                 namelen += 2;
563
564         for (i = 0; i < LOCKSTAT_POINTS; i++) {
565                 char sym[KSYM_SYMBOL_LEN];
566                 char ip[32];
567
568                 if (class->contention_point[i] == 0)
569                         break;
570
571                 if (!i)
572                         seq_line(m, '-', 40-namelen, namelen);
573
574                 sprint_symbol(sym, class->contention_point[i]);
575                 snprintf(ip, sizeof(ip), "[<%p>]",
576                                 (void *)class->contention_point[i]);
577                 seq_printf(m, "%40s %14lu %29s %s\n", name,
578                                 stats->contention_point[i],
579                                 ip, sym);
580         }
581         for (i = 0; i < LOCKSTAT_POINTS; i++) {
582                 char sym[KSYM_SYMBOL_LEN];
583                 char ip[32];
584
585                 if (class->contending_point[i] == 0)
586                         break;
587
588                 if (!i)
589                         seq_line(m, '-', 40-namelen, namelen);
590
591                 sprint_symbol(sym, class->contending_point[i]);
592                 snprintf(ip, sizeof(ip), "[<%p>]",
593                                 (void *)class->contending_point[i]);
594                 seq_printf(m, "%40s %14lu %29s %s\n", name,
595                                 stats->contending_point[i],
596                                 ip, sym);
597         }
598         if (i) {
599                 seq_puts(m, "\n");
600                 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
601                 seq_puts(m, "\n");
602         }
603 }
604
605 static void seq_header(struct seq_file *m)
606 {
607         seq_printf(m, "lock_stat version 0.3\n");
608
609         if (unlikely(!debug_locks))
610                 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
611
612         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
613         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
614                         "%14s %14s\n",
615                         "class name",
616                         "con-bounces",
617                         "contentions",
618                         "waittime-min",
619                         "waittime-max",
620                         "waittime-total",
621                         "acq-bounces",
622                         "acquisitions",
623                         "holdtime-min",
624                         "holdtime-max",
625                         "holdtime-total");
626         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
627         seq_printf(m, "\n");
628 }
629
630 static void *ls_start(struct seq_file *m, loff_t *pos)
631 {
632         struct lock_stat_seq *data = m->private;
633
634         if (*pos == 0)
635                 return SEQ_START_TOKEN;
636
637         data->iter = data->stats + *pos;
638         if (data->iter >= data->iter_end)
639                 data->iter = NULL;
640
641         return data->iter;
642 }
643
644 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
645 {
646         struct lock_stat_seq *data = m->private;
647
648         (*pos)++;
649
650         if (v == SEQ_START_TOKEN)
651                 data->iter = data->stats;
652         else {
653                 data->iter = v;
654                 data->iter++;
655         }
656
657         if (data->iter == data->iter_end)
658                 data->iter = NULL;
659
660         return data->iter;
661 }
662
663 static void ls_stop(struct seq_file *m, void *v)
664 {
665 }
666
667 static int ls_show(struct seq_file *m, void *v)
668 {
669         if (v == SEQ_START_TOKEN)
670                 seq_header(m);
671         else
672                 seq_stats(m, v);
673
674         return 0;
675 }
676
677 static struct seq_operations lockstat_ops = {
678         .start  = ls_start,
679         .next   = ls_next,
680         .stop   = ls_stop,
681         .show   = ls_show,
682 };
683
684 static int lock_stat_open(struct inode *inode, struct file *file)
685 {
686         int res;
687         struct lock_class *class;
688         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
689
690         if (!data)
691                 return -ENOMEM;
692
693         res = seq_open(file, &lockstat_ops);
694         if (!res) {
695                 struct lock_stat_data *iter = data->stats;
696                 struct seq_file *m = file->private_data;
697
698                 data->iter = iter;
699                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
700                         iter->class = class;
701                         iter->stats = lock_stats(class);
702                         iter++;
703                 }
704                 data->iter_end = iter;
705
706                 sort(data->stats, data->iter_end - data->iter,
707                                 sizeof(struct lock_stat_data),
708                                 lock_stat_cmp, NULL);
709
710                 m->private = data;
711         } else
712                 vfree(data);
713
714         return res;
715 }
716
717 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
718                                size_t count, loff_t *ppos)
719 {
720         struct lock_class *class;
721         char c;
722
723         if (count) {
724                 if (get_user(c, buf))
725                         return -EFAULT;
726
727                 if (c != '0')
728                         return count;
729
730                 list_for_each_entry(class, &all_lock_classes, lock_entry)
731                         clear_lock_stats(class);
732         }
733         return count;
734 }
735
736 static int lock_stat_release(struct inode *inode, struct file *file)
737 {
738         struct seq_file *seq = file->private_data;
739
740         vfree(seq->private);
741         seq->private = NULL;
742         return seq_release(inode, file);
743 }
744
745 static const struct file_operations proc_lock_stat_operations = {
746         .open           = lock_stat_open,
747         .write          = lock_stat_write,
748         .read           = seq_read,
749         .llseek         = seq_lseek,
750         .release        = lock_stat_release,
751 };
752 #endif /* CONFIG_LOCK_STAT */
753
754 static int __init lockdep_proc_init(void)
755 {
756         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
757 #ifdef CONFIG_PROVE_LOCKING
758         proc_create("lockdep_chains", S_IRUSR, NULL,
759                     &proc_lockdep_chains_operations);
760 #endif
761         proc_create("lockdep_stats", S_IRUSR, NULL,
762                     &proc_lockdep_stats_operations);
763
764 #ifdef CONFIG_LOCK_STAT
765         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
766 #endif
767
768         return 0;
769 }
770
771 __initcall(lockdep_proc_init);
772