lockdep: add lock_class information to lock_chain and output it
[linux-3.10.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 unsigned long count_forward_deps(struct lock_class *class)
67 {
68         struct lock_list *entry;
69         unsigned long ret = 1;
70
71         /*
72          * Recurse this class's dependency list:
73          */
74         list_for_each_entry(entry, &class->locks_after, entry)
75                 ret += count_forward_deps(entry->class);
76
77         return ret;
78 }
79
80 static unsigned long count_backward_deps(struct lock_class *class)
81 {
82         struct lock_list *entry;
83         unsigned long ret = 1;
84
85         /*
86          * Recurse this class's dependency list:
87          */
88         list_for_each_entry(entry, &class->locks_before, entry)
89                 ret += count_backward_deps(entry->class);
90
91         return ret;
92 }
93
94 static void print_name(struct seq_file *m, struct lock_class *class)
95 {
96         char str[128];
97         const char *name = class->name;
98
99         if (!name) {
100                 name = __get_key_name(class->key, str);
101                 seq_printf(m, "%s", name);
102         } else{
103                 seq_printf(m, "%s", name);
104                 if (class->name_version > 1)
105                         seq_printf(m, "#%d", class->name_version);
106                 if (class->subclass)
107                         seq_printf(m, "/%d", class->subclass);
108         }
109 }
110
111 static int l_show(struct seq_file *m, void *v)
112 {
113         unsigned long nr_forward_deps, nr_backward_deps;
114         struct lock_class *class = v;
115         struct lock_list *entry;
116         char c1, c2, c3, c4;
117
118         if (v == SEQ_START_TOKEN) {
119                 seq_printf(m, "all lock classes:\n");
120                 return 0;
121         }
122
123         seq_printf(m, "%p", class->key);
124 #ifdef CONFIG_DEBUG_LOCKDEP
125         seq_printf(m, " OPS:%8ld", class->ops);
126 #endif
127         nr_forward_deps = count_forward_deps(class);
128         seq_printf(m, " FD:%5ld", nr_forward_deps);
129
130         nr_backward_deps = count_backward_deps(class);
131         seq_printf(m, " BD:%5ld", nr_backward_deps);
132
133         get_usage_chars(class, &c1, &c2, &c3, &c4);
134         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
135
136         seq_printf(m, ": ");
137         print_name(m, class);
138         seq_puts(m, "\n");
139
140         list_for_each_entry(entry, &class->locks_after, entry) {
141                 if (entry->distance == 1) {
142                         seq_printf(m, " -> [%p] ", entry->class->key);
143                         print_name(m, entry->class);
144                         seq_puts(m, "\n");
145                 }
146         }
147         seq_puts(m, "\n");
148
149         return 0;
150 }
151
152 static const struct seq_operations lockdep_ops = {
153         .start  = l_start,
154         .next   = l_next,
155         .stop   = l_stop,
156         .show   = l_show,
157 };
158
159 static int lockdep_open(struct inode *inode, struct file *file)
160 {
161         int res = seq_open(file, &lockdep_ops);
162         if (!res) {
163                 struct seq_file *m = file->private_data;
164
165                 if (!list_empty(&all_lock_classes))
166                         m->private = list_entry(all_lock_classes.next,
167                                         struct lock_class, lock_entry);
168                 else
169                         m->private = NULL;
170         }
171         return res;
172 }
173
174 static const struct file_operations proc_lockdep_operations = {
175         .open           = lockdep_open,
176         .read           = seq_read,
177         .llseek         = seq_lseek,
178         .release        = seq_release,
179 };
180
181 #ifdef CONFIG_PROVE_LOCKING
182 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
183 {
184         struct lock_chain *chain;
185
186         (*pos)++;
187
188         if (v == SEQ_START_TOKEN)
189                 chain = m->private;
190         else {
191                 chain = v;
192
193                 if (*pos < nr_lock_chains)
194                         chain = lock_chains + *pos;
195                 else
196                         chain = NULL;
197         }
198
199         return chain;
200 }
201
202 static void *lc_start(struct seq_file *m, loff_t *pos)
203 {
204         if (*pos == 0)
205                 return SEQ_START_TOKEN;
206
207         if (*pos < nr_lock_chains)
208                 return lock_chains + *pos;
209
210         return NULL;
211 }
212
213 static void lc_stop(struct seq_file *m, void *v)
214 {
215 }
216
217 static int lc_show(struct seq_file *m, void *v)
218 {
219         struct lock_chain *chain = v;
220         struct lock_class *class;
221         int i;
222
223         if (v == SEQ_START_TOKEN) {
224                 seq_printf(m, "all lock chains:\n");
225                 return 0;
226         }
227
228         seq_printf(m, "irq_context: %d\n", chain->irq_context);
229
230         for (i = 0; i < chain->depth; i++) {
231                 class = lock_chain_get_class(chain, i);
232                 seq_printf(m, "[%p] ", class->key);
233                 print_name(m, class);
234                 seq_puts(m, "\n");
235         }
236         seq_puts(m, "\n");
237
238         return 0;
239 }
240
241 static const struct seq_operations lockdep_chains_ops = {
242         .start  = lc_start,
243         .next   = lc_next,
244         .stop   = lc_stop,
245         .show   = lc_show,
246 };
247
248 static int lockdep_chains_open(struct inode *inode, struct file *file)
249 {
250         int res = seq_open(file, &lockdep_chains_ops);
251         if (!res) {
252                 struct seq_file *m = file->private_data;
253
254                 if (nr_lock_chains)
255                         m->private = lock_chains;
256                 else
257                         m->private = NULL;
258         }
259         return res;
260 }
261
262 static const struct file_operations proc_lockdep_chains_operations = {
263         .open           = lockdep_chains_open,
264         .read           = seq_read,
265         .llseek         = seq_lseek,
266         .release        = seq_release,
267 };
268 #endif /* CONFIG_PROVE_LOCKING */
269
270 static void lockdep_stats_debug_show(struct seq_file *m)
271 {
272 #ifdef CONFIG_DEBUG_LOCKDEP
273         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
274                      hi2 = debug_atomic_read(&hardirqs_off_events),
275                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
276                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
277                      si1 = debug_atomic_read(&softirqs_on_events),
278                      si2 = debug_atomic_read(&softirqs_off_events),
279                      sr1 = debug_atomic_read(&redundant_softirqs_on),
280                      sr2 = debug_atomic_read(&redundant_softirqs_off);
281
282         seq_printf(m, " chain lookup misses:           %11u\n",
283                 debug_atomic_read(&chain_lookup_misses));
284         seq_printf(m, " chain lookup hits:             %11u\n",
285                 debug_atomic_read(&chain_lookup_hits));
286         seq_printf(m, " cyclic checks:                 %11u\n",
287                 debug_atomic_read(&nr_cyclic_checks));
288         seq_printf(m, " cyclic-check recursions:       %11u\n",
289                 debug_atomic_read(&nr_cyclic_check_recursions));
290         seq_printf(m, " find-mask forwards checks:     %11u\n",
291                 debug_atomic_read(&nr_find_usage_forwards_checks));
292         seq_printf(m, " find-mask forwards recursions: %11u\n",
293                 debug_atomic_read(&nr_find_usage_forwards_recursions));
294         seq_printf(m, " find-mask backwards checks:    %11u\n",
295                 debug_atomic_read(&nr_find_usage_backwards_checks));
296         seq_printf(m, " find-mask backwards recursions:%11u\n",
297                 debug_atomic_read(&nr_find_usage_backwards_recursions));
298
299         seq_printf(m, " hardirq on events:             %11u\n", hi1);
300         seq_printf(m, " hardirq off events:            %11u\n", hi2);
301         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
302         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
303         seq_printf(m, " softirq on events:             %11u\n", si1);
304         seq_printf(m, " softirq off events:            %11u\n", si2);
305         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
306         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
307 #endif
308 }
309
310 static int lockdep_stats_show(struct seq_file *m, void *v)
311 {
312         struct lock_class *class;
313         unsigned long nr_unused = 0, nr_uncategorized = 0,
314                       nr_irq_safe = 0, nr_irq_unsafe = 0,
315                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
316                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
317                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
318                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
319                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
320                       sum_forward_deps = 0, factor = 0;
321
322         list_for_each_entry(class, &all_lock_classes, lock_entry) {
323
324                 if (class->usage_mask == 0)
325                         nr_unused++;
326                 if (class->usage_mask == LOCKF_USED)
327                         nr_uncategorized++;
328                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
329                         nr_irq_safe++;
330                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
331                         nr_irq_unsafe++;
332                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
333                         nr_softirq_safe++;
334                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
335                         nr_softirq_unsafe++;
336                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
337                         nr_hardirq_safe++;
338                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
339                         nr_hardirq_unsafe++;
340                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
341                         nr_irq_read_safe++;
342                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
343                         nr_irq_read_unsafe++;
344                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
345                         nr_softirq_read_safe++;
346                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
347                         nr_softirq_read_unsafe++;
348                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
349                         nr_hardirq_read_safe++;
350                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
351                         nr_hardirq_read_unsafe++;
352
353                 sum_forward_deps += count_forward_deps(class);
354         }
355 #ifdef CONFIG_DEBUG_LOCKDEP
356         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
357 #endif
358         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
359                         nr_lock_classes, MAX_LOCKDEP_KEYS);
360         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
361                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
362         seq_printf(m, " indirect dependencies:         %11lu\n",
363                         sum_forward_deps);
364
365         /*
366          * Total number of dependencies:
367          *
368          * All irq-safe locks may nest inside irq-unsafe locks,
369          * plus all the other known dependencies:
370          */
371         seq_printf(m, " all direct dependencies:       %11lu\n",
372                         nr_irq_unsafe * nr_irq_safe +
373                         nr_hardirq_unsafe * nr_hardirq_safe +
374                         nr_list_entries);
375
376         /*
377          * Estimated factor between direct and indirect
378          * dependencies:
379          */
380         if (nr_list_entries)
381                 factor = sum_forward_deps / nr_list_entries;
382
383 #ifdef CONFIG_PROVE_LOCKING
384         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
385                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
386         seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
387                         nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
388 #endif
389
390 #ifdef CONFIG_TRACE_IRQFLAGS
391         seq_printf(m, " in-hardirq chains:             %11u\n",
392                         nr_hardirq_chains);
393         seq_printf(m, " in-softirq chains:             %11u\n",
394                         nr_softirq_chains);
395 #endif
396         seq_printf(m, " in-process chains:             %11u\n",
397                         nr_process_chains);
398         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
399                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
400         seq_printf(m, " combined max dependencies:     %11u\n",
401                         (nr_hardirq_chains + 1) *
402                         (nr_softirq_chains + 1) *
403                         (nr_process_chains + 1)
404         );
405         seq_printf(m, " hardirq-safe locks:            %11lu\n",
406                         nr_hardirq_safe);
407         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
408                         nr_hardirq_unsafe);
409         seq_printf(m, " softirq-safe locks:            %11lu\n",
410                         nr_softirq_safe);
411         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
412                         nr_softirq_unsafe);
413         seq_printf(m, " irq-safe locks:                %11lu\n",
414                         nr_irq_safe);
415         seq_printf(m, " irq-unsafe locks:              %11lu\n",
416                         nr_irq_unsafe);
417
418         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
419                         nr_hardirq_read_safe);
420         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
421                         nr_hardirq_read_unsafe);
422         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
423                         nr_softirq_read_safe);
424         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
425                         nr_softirq_read_unsafe);
426         seq_printf(m, " irq-read-safe locks:           %11lu\n",
427                         nr_irq_read_safe);
428         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
429                         nr_irq_read_unsafe);
430
431         seq_printf(m, " uncategorized locks:           %11lu\n",
432                         nr_uncategorized);
433         seq_printf(m, " unused locks:                  %11lu\n",
434                         nr_unused);
435         seq_printf(m, " max locking depth:             %11u\n",
436                         max_lockdep_depth);
437         seq_printf(m, " max recursion depth:           %11u\n",
438                         max_recursion_depth);
439         lockdep_stats_debug_show(m);
440         seq_printf(m, " debug_locks:                   %11u\n",
441                         debug_locks);
442
443         return 0;
444 }
445
446 static int lockdep_stats_open(struct inode *inode, struct file *file)
447 {
448         return single_open(file, lockdep_stats_show, NULL);
449 }
450
451 static const struct file_operations proc_lockdep_stats_operations = {
452         .open           = lockdep_stats_open,
453         .read           = seq_read,
454         .llseek         = seq_lseek,
455         .release        = single_release,
456 };
457
458 #ifdef CONFIG_LOCK_STAT
459
460 struct lock_stat_data {
461         struct lock_class *class;
462         struct lock_class_stats stats;
463 };
464
465 struct lock_stat_seq {
466         struct lock_stat_data *iter;
467         struct lock_stat_data *iter_end;
468         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
469 };
470
471 /*
472  * sort on absolute number of contentions
473  */
474 static int lock_stat_cmp(const void *l, const void *r)
475 {
476         const struct lock_stat_data *dl = l, *dr = r;
477         unsigned long nl, nr;
478
479         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
480         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
481
482         return nr - nl;
483 }
484
485 static void seq_line(struct seq_file *m, char c, int offset, int length)
486 {
487         int i;
488
489         for (i = 0; i < offset; i++)
490                 seq_puts(m, " ");
491         for (i = 0; i < length; i++)
492                 seq_printf(m, "%c", c);
493         seq_puts(m, "\n");
494 }
495
496 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
497 {
498         unsigned long rem;
499
500         rem = do_div(nr, 1000); /* XXX: do_div_signed */
501         snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
502 }
503
504 static void seq_time(struct seq_file *m, s64 time)
505 {
506         char num[15];
507
508         snprint_time(num, sizeof(num), time);
509         seq_printf(m, " %14s", num);
510 }
511
512 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
513 {
514         seq_printf(m, "%14lu", lt->nr);
515         seq_time(m, lt->min);
516         seq_time(m, lt->max);
517         seq_time(m, lt->total);
518 }
519
520 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
521 {
522         char name[39];
523         struct lock_class *class;
524         struct lock_class_stats *stats;
525         int i, namelen;
526
527         class = data->class;
528         stats = &data->stats;
529
530         namelen = 38;
531         if (class->name_version > 1)
532                 namelen -= 2; /* XXX truncates versions > 9 */
533         if (class->subclass)
534                 namelen -= 2;
535
536         if (!class->name) {
537                 char str[KSYM_NAME_LEN];
538                 const char *key_name;
539
540                 key_name = __get_key_name(class->key, str);
541                 snprintf(name, namelen, "%s", key_name);
542         } else {
543                 snprintf(name, namelen, "%s", class->name);
544         }
545         namelen = strlen(name);
546         if (class->name_version > 1) {
547                 snprintf(name+namelen, 3, "#%d", class->name_version);
548                 namelen += 2;
549         }
550         if (class->subclass) {
551                 snprintf(name+namelen, 3, "/%d", class->subclass);
552                 namelen += 2;
553         }
554
555         if (stats->write_holdtime.nr) {
556                 if (stats->read_holdtime.nr)
557                         seq_printf(m, "%38s-W:", name);
558                 else
559                         seq_printf(m, "%40s:", name);
560
561                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
562                 seq_lock_time(m, &stats->write_waittime);
563                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
564                 seq_lock_time(m, &stats->write_holdtime);
565                 seq_puts(m, "\n");
566         }
567
568         if (stats->read_holdtime.nr) {
569                 seq_printf(m, "%38s-R:", name);
570                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
571                 seq_lock_time(m, &stats->read_waittime);
572                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
573                 seq_lock_time(m, &stats->read_holdtime);
574                 seq_puts(m, "\n");
575         }
576
577         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
578                 return;
579
580         if (stats->read_holdtime.nr)
581                 namelen += 2;
582
583         for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
584                 char sym[KSYM_SYMBOL_LEN];
585                 char ip[32];
586
587                 if (class->contention_point[i] == 0)
588                         break;
589
590                 if (!i)
591                         seq_line(m, '-', 40-namelen, namelen);
592
593                 sprint_symbol(sym, class->contention_point[i]);
594                 snprintf(ip, sizeof(ip), "[<%p>]",
595                                 (void *)class->contention_point[i]);
596                 seq_printf(m, "%40s %14lu %29s %s\n", name,
597                                 stats->contention_point[i],
598                                 ip, sym);
599         }
600         if (i) {
601                 seq_puts(m, "\n");
602                 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
603                 seq_puts(m, "\n");
604         }
605 }
606
607 static void seq_header(struct seq_file *m)
608 {
609         seq_printf(m, "lock_stat version 0.2\n");
610         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
611         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
612                         "%14s %14s\n",
613                         "class name",
614                         "con-bounces",
615                         "contentions",
616                         "waittime-min",
617                         "waittime-max",
618                         "waittime-total",
619                         "acq-bounces",
620                         "acquisitions",
621                         "holdtime-min",
622                         "holdtime-max",
623                         "holdtime-total");
624         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
625         seq_printf(m, "\n");
626 }
627
628 static void *ls_start(struct seq_file *m, loff_t *pos)
629 {
630         struct lock_stat_seq *data = m->private;
631
632         if (*pos == 0)
633                 return SEQ_START_TOKEN;
634
635         data->iter = data->stats + *pos;
636         if (data->iter >= data->iter_end)
637                 data->iter = NULL;
638
639         return data->iter;
640 }
641
642 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
643 {
644         struct lock_stat_seq *data = m->private;
645
646         (*pos)++;
647
648         if (v == SEQ_START_TOKEN)
649                 data->iter = data->stats;
650         else {
651                 data->iter = v;
652                 data->iter++;
653         }
654
655         if (data->iter == data->iter_end)
656                 data->iter = NULL;
657
658         return data->iter;
659 }
660
661 static void ls_stop(struct seq_file *m, void *v)
662 {
663 }
664
665 static int ls_show(struct seq_file *m, void *v)
666 {
667         if (v == SEQ_START_TOKEN)
668                 seq_header(m);
669         else
670                 seq_stats(m, v);
671
672         return 0;
673 }
674
675 static struct seq_operations lockstat_ops = {
676         .start  = ls_start,
677         .next   = ls_next,
678         .stop   = ls_stop,
679         .show   = ls_show,
680 };
681
682 static int lock_stat_open(struct inode *inode, struct file *file)
683 {
684         int res;
685         struct lock_class *class;
686         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
687
688         if (!data)
689                 return -ENOMEM;
690
691         res = seq_open(file, &lockstat_ops);
692         if (!res) {
693                 struct lock_stat_data *iter = data->stats;
694                 struct seq_file *m = file->private_data;
695
696                 data->iter = iter;
697                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
698                         iter->class = class;
699                         iter->stats = lock_stats(class);
700                         iter++;
701                 }
702                 data->iter_end = iter;
703
704                 sort(data->stats, data->iter_end - data->iter,
705                                 sizeof(struct lock_stat_data),
706                                 lock_stat_cmp, NULL);
707
708                 m->private = data;
709         } else
710                 vfree(data);
711
712         return res;
713 }
714
715 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
716                                size_t count, loff_t *ppos)
717 {
718         struct lock_class *class;
719         char c;
720
721         if (count) {
722                 if (get_user(c, buf))
723                         return -EFAULT;
724
725                 if (c != '0')
726                         return count;
727
728                 list_for_each_entry(class, &all_lock_classes, lock_entry)
729                         clear_lock_stats(class);
730         }
731         return count;
732 }
733
734 static int lock_stat_release(struct inode *inode, struct file *file)
735 {
736         struct seq_file *seq = file->private_data;
737
738         vfree(seq->private);
739         seq->private = NULL;
740         return seq_release(inode, file);
741 }
742
743 static const struct file_operations proc_lock_stat_operations = {
744         .open           = lock_stat_open,
745         .write          = lock_stat_write,
746         .read           = seq_read,
747         .llseek         = seq_lseek,
748         .release        = lock_stat_release,
749 };
750 #endif /* CONFIG_LOCK_STAT */
751
752 static int __init lockdep_proc_init(void)
753 {
754         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
755 #ifdef CONFIG_PROVE_LOCKING
756         proc_create("lockdep_chains", S_IRUSR, NULL,
757                     &proc_lockdep_chains_operations);
758 #endif
759         proc_create("lockdep_stats", S_IRUSR, NULL,
760                     &proc_lockdep_stats_operations);
761
762 #ifdef CONFIG_LOCK_STAT
763         proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
764 #endif
765
766         return 0;
767 }
768
769 __initcall(lockdep_proc_init);
770