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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/export.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 
l_next(struct seq_file * m,void * v,loff_t * pos)26 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
27 {
28 	return seq_list_next(v, &all_lock_classes, pos);
29 }
30 
l_start(struct seq_file * m,loff_t * pos)31 static void *l_start(struct seq_file *m, loff_t *pos)
32 {
33 	return seq_list_start_head(&all_lock_classes, *pos);
34 }
35 
l_stop(struct seq_file * m,void * v)36 static void l_stop(struct seq_file *m, void *v)
37 {
38 }
39 
print_name(struct seq_file * m,struct lock_class * class)40 static void print_name(struct seq_file *m, struct lock_class *class)
41 {
42 	char str[KSYM_NAME_LEN];
43 	const char *name = class->name;
44 
45 	if (!name) {
46 		name = __get_key_name(class->key, str);
47 		seq_printf(m, "%s", name);
48 	} else{
49 		seq_printf(m, "%s", name);
50 		if (class->name_version > 1)
51 			seq_printf(m, "#%d", class->name_version);
52 		if (class->subclass)
53 			seq_printf(m, "/%d", class->subclass);
54 	}
55 }
56 
l_show(struct seq_file * m,void * v)57 static int l_show(struct seq_file *m, void *v)
58 {
59 	struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
60 	struct lock_list *entry;
61 	char usage[LOCK_USAGE_CHARS];
62 
63 	if (v == &all_lock_classes) {
64 		seq_printf(m, "all lock classes:\n");
65 		return 0;
66 	}
67 
68 	seq_printf(m, "%p", class->key);
69 #ifdef CONFIG_DEBUG_LOCKDEP
70 	seq_printf(m, " OPS:%8ld", class->ops);
71 #endif
72 #ifdef CONFIG_PROVE_LOCKING
73 	seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
74 	seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
75 #endif
76 
77 	get_usage_chars(class, usage);
78 	seq_printf(m, " %s", usage);
79 
80 	seq_printf(m, ": ");
81 	print_name(m, class);
82 	seq_puts(m, "\n");
83 
84 	list_for_each_entry(entry, &class->locks_after, entry) {
85 		if (entry->distance == 1) {
86 			seq_printf(m, " -> [%p] ", entry->class->key);
87 			print_name(m, entry->class);
88 			seq_puts(m, "\n");
89 		}
90 	}
91 	seq_puts(m, "\n");
92 
93 	return 0;
94 }
95 
96 static const struct seq_operations lockdep_ops = {
97 	.start	= l_start,
98 	.next	= l_next,
99 	.stop	= l_stop,
100 	.show	= l_show,
101 };
102 
lockdep_open(struct inode * inode,struct file * file)103 static int lockdep_open(struct inode *inode, struct file *file)
104 {
105 	return seq_open(file, &lockdep_ops);
106 }
107 
108 static const struct file_operations proc_lockdep_operations = {
109 	.open		= lockdep_open,
110 	.read		= seq_read,
111 	.llseek		= seq_lseek,
112 	.release	= seq_release,
113 };
114 
115 #ifdef CONFIG_PROVE_LOCKING
lc_start(struct seq_file * m,loff_t * pos)116 static void *lc_start(struct seq_file *m, loff_t *pos)
117 {
118 	if (*pos == 0)
119 		return SEQ_START_TOKEN;
120 
121 	if (*pos - 1 < nr_lock_chains)
122 		return lock_chains + (*pos - 1);
123 
124 	return NULL;
125 }
126 
lc_next(struct seq_file * m,void * v,loff_t * pos)127 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
128 {
129 	(*pos)++;
130 	return lc_start(m, pos);
131 }
132 
lc_stop(struct seq_file * m,void * v)133 static void lc_stop(struct seq_file *m, void *v)
134 {
135 }
136 
lc_show(struct seq_file * m,void * v)137 static int lc_show(struct seq_file *m, void *v)
138 {
139 	struct lock_chain *chain = v;
140 	struct lock_class *class;
141 	int i;
142 
143 	if (v == SEQ_START_TOKEN) {
144 		seq_printf(m, "all lock chains:\n");
145 		return 0;
146 	}
147 
148 	seq_printf(m, "irq_context: %d\n", chain->irq_context);
149 
150 	for (i = 0; i < chain->depth; i++) {
151 		class = lock_chain_get_class(chain, i);
152 		if (!class->key)
153 			continue;
154 
155 		seq_printf(m, "[%p] ", class->key);
156 		print_name(m, class);
157 		seq_puts(m, "\n");
158 	}
159 	seq_puts(m, "\n");
160 
161 	return 0;
162 }
163 
164 static const struct seq_operations lockdep_chains_ops = {
165 	.start	= lc_start,
166 	.next	= lc_next,
167 	.stop	= lc_stop,
168 	.show	= lc_show,
169 };
170 
lockdep_chains_open(struct inode * inode,struct file * file)171 static int lockdep_chains_open(struct inode *inode, struct file *file)
172 {
173 	return seq_open(file, &lockdep_chains_ops);
174 }
175 
176 static const struct file_operations proc_lockdep_chains_operations = {
177 	.open		= lockdep_chains_open,
178 	.read		= seq_read,
179 	.llseek		= seq_lseek,
180 	.release	= seq_release,
181 };
182 #endif /* CONFIG_PROVE_LOCKING */
183 
lockdep_stats_debug_show(struct seq_file * m)184 static void lockdep_stats_debug_show(struct seq_file *m)
185 {
186 #ifdef CONFIG_DEBUG_LOCKDEP
187 	unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
188 			   hi2 = debug_atomic_read(hardirqs_off_events),
189 			   hr1 = debug_atomic_read(redundant_hardirqs_on),
190 			   hr2 = debug_atomic_read(redundant_hardirqs_off),
191 			   si1 = debug_atomic_read(softirqs_on_events),
192 			   si2 = debug_atomic_read(softirqs_off_events),
193 			   sr1 = debug_atomic_read(redundant_softirqs_on),
194 			   sr2 = debug_atomic_read(redundant_softirqs_off);
195 
196 	seq_printf(m, " chain lookup misses:           %11llu\n",
197 		debug_atomic_read(chain_lookup_misses));
198 	seq_printf(m, " chain lookup hits:             %11llu\n",
199 		debug_atomic_read(chain_lookup_hits));
200 	seq_printf(m, " cyclic checks:                 %11llu\n",
201 		debug_atomic_read(nr_cyclic_checks));
202 	seq_printf(m, " find-mask forwards checks:     %11llu\n",
203 		debug_atomic_read(nr_find_usage_forwards_checks));
204 	seq_printf(m, " find-mask backwards checks:    %11llu\n",
205 		debug_atomic_read(nr_find_usage_backwards_checks));
206 
207 	seq_printf(m, " hardirq on events:             %11llu\n", hi1);
208 	seq_printf(m, " hardirq off events:            %11llu\n", hi2);
209 	seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
210 	seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
211 	seq_printf(m, " softirq on events:             %11llu\n", si1);
212 	seq_printf(m, " softirq off events:            %11llu\n", si2);
213 	seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
214 	seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
215 #endif
216 }
217 
lockdep_stats_show(struct seq_file * m,void * v)218 static int lockdep_stats_show(struct seq_file *m, void *v)
219 {
220 	struct lock_class *class;
221 	unsigned long nr_unused = 0, nr_uncategorized = 0,
222 		      nr_irq_safe = 0, nr_irq_unsafe = 0,
223 		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
224 		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
225 		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
226 		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
227 		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
228 		      sum_forward_deps = 0;
229 
230 	list_for_each_entry(class, &all_lock_classes, lock_entry) {
231 
232 		if (class->usage_mask == 0)
233 			nr_unused++;
234 		if (class->usage_mask == LOCKF_USED)
235 			nr_uncategorized++;
236 		if (class->usage_mask & LOCKF_USED_IN_IRQ)
237 			nr_irq_safe++;
238 		if (class->usage_mask & LOCKF_ENABLED_IRQ)
239 			nr_irq_unsafe++;
240 		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
241 			nr_softirq_safe++;
242 		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
243 			nr_softirq_unsafe++;
244 		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
245 			nr_hardirq_safe++;
246 		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
247 			nr_hardirq_unsafe++;
248 		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
249 			nr_irq_read_safe++;
250 		if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
251 			nr_irq_read_unsafe++;
252 		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
253 			nr_softirq_read_safe++;
254 		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
255 			nr_softirq_read_unsafe++;
256 		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
257 			nr_hardirq_read_safe++;
258 		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
259 			nr_hardirq_read_unsafe++;
260 
261 #ifdef CONFIG_PROVE_LOCKING
262 		sum_forward_deps += lockdep_count_forward_deps(class);
263 #endif
264 	}
265 #ifdef CONFIG_DEBUG_LOCKDEP
266 	DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
267 #endif
268 	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
269 			nr_lock_classes, MAX_LOCKDEP_KEYS);
270 	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
271 			nr_list_entries, MAX_LOCKDEP_ENTRIES);
272 	seq_printf(m, " indirect dependencies:         %11lu\n",
273 			sum_forward_deps);
274 
275 	/*
276 	 * Total number of dependencies:
277 	 *
278 	 * All irq-safe locks may nest inside irq-unsafe locks,
279 	 * plus all the other known dependencies:
280 	 */
281 	seq_printf(m, " all direct dependencies:       %11lu\n",
282 			nr_irq_unsafe * nr_irq_safe +
283 			nr_hardirq_unsafe * nr_hardirq_safe +
284 			nr_list_entries);
285 
286 #ifdef CONFIG_PROVE_LOCKING
287 	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
288 			nr_lock_chains, MAX_LOCKDEP_CHAINS);
289 	seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
290 			nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
291 #endif
292 
293 #ifdef CONFIG_TRACE_IRQFLAGS
294 	seq_printf(m, " in-hardirq chains:             %11u\n",
295 			nr_hardirq_chains);
296 	seq_printf(m, " in-softirq chains:             %11u\n",
297 			nr_softirq_chains);
298 #endif
299 	seq_printf(m, " in-process chains:             %11u\n",
300 			nr_process_chains);
301 	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
302 			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
303 	seq_printf(m, " combined max dependencies:     %11u\n",
304 			(nr_hardirq_chains + 1) *
305 			(nr_softirq_chains + 1) *
306 			(nr_process_chains + 1)
307 	);
308 	seq_printf(m, " hardirq-safe locks:            %11lu\n",
309 			nr_hardirq_safe);
310 	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
311 			nr_hardirq_unsafe);
312 	seq_printf(m, " softirq-safe locks:            %11lu\n",
313 			nr_softirq_safe);
314 	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
315 			nr_softirq_unsafe);
316 	seq_printf(m, " irq-safe locks:                %11lu\n",
317 			nr_irq_safe);
318 	seq_printf(m, " irq-unsafe locks:              %11lu\n",
319 			nr_irq_unsafe);
320 
321 	seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
322 			nr_hardirq_read_safe);
323 	seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
324 			nr_hardirq_read_unsafe);
325 	seq_printf(m, " softirq-read-safe locks:       %11lu\n",
326 			nr_softirq_read_safe);
327 	seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
328 			nr_softirq_read_unsafe);
329 	seq_printf(m, " irq-read-safe locks:           %11lu\n",
330 			nr_irq_read_safe);
331 	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
332 			nr_irq_read_unsafe);
333 
334 	seq_printf(m, " uncategorized locks:           %11lu\n",
335 			nr_uncategorized);
336 	seq_printf(m, " unused locks:                  %11lu\n",
337 			nr_unused);
338 	seq_printf(m, " max locking depth:             %11u\n",
339 			max_lockdep_depth);
340 #ifdef CONFIG_PROVE_LOCKING
341 	seq_printf(m, " max bfs queue depth:           %11u\n",
342 			max_bfs_queue_depth);
343 #endif
344 	lockdep_stats_debug_show(m);
345 	seq_printf(m, " debug_locks:                   %11u\n",
346 			debug_locks);
347 
348 	return 0;
349 }
350 
lockdep_stats_open(struct inode * inode,struct file * file)351 static int lockdep_stats_open(struct inode *inode, struct file *file)
352 {
353 	return single_open(file, lockdep_stats_show, NULL);
354 }
355 
356 static const struct file_operations proc_lockdep_stats_operations = {
357 	.open		= lockdep_stats_open,
358 	.read		= seq_read,
359 	.llseek		= seq_lseek,
360 	.release	= single_release,
361 };
362 
363 #ifdef CONFIG_LOCK_STAT
364 
365 struct lock_stat_data {
366 	struct lock_class *class;
367 	struct lock_class_stats stats;
368 };
369 
370 struct lock_stat_seq {
371 	struct lock_stat_data *iter_end;
372 	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
373 };
374 
375 /*
376  * sort on absolute number of contentions
377  */
lock_stat_cmp(const void * l,const void * r)378 static int lock_stat_cmp(const void *l, const void *r)
379 {
380 	const struct lock_stat_data *dl = l, *dr = r;
381 	unsigned long nl, nr;
382 
383 	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
384 	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
385 
386 	return nr - nl;
387 }
388 
seq_line(struct seq_file * m,char c,int offset,int length)389 static void seq_line(struct seq_file *m, char c, int offset, int length)
390 {
391 	int i;
392 
393 	for (i = 0; i < offset; i++)
394 		seq_puts(m, " ");
395 	for (i = 0; i < length; i++)
396 		seq_printf(m, "%c", c);
397 	seq_puts(m, "\n");
398 }
399 
snprint_time(char * buf,size_t bufsiz,s64 nr)400 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
401 {
402 	s64 div;
403 	s32 rem;
404 
405 	nr += 5; /* for display rounding */
406 	div = div_s64_rem(nr, 1000, &rem);
407 	snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
408 }
409 
seq_time(struct seq_file * m,s64 time)410 static void seq_time(struct seq_file *m, s64 time)
411 {
412 	char num[15];
413 
414 	snprint_time(num, sizeof(num), time);
415 	seq_printf(m, " %14s", num);
416 }
417 
seq_lock_time(struct seq_file * m,struct lock_time * lt)418 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
419 {
420 	seq_printf(m, "%14lu", lt->nr);
421 	seq_time(m, lt->min);
422 	seq_time(m, lt->max);
423 	seq_time(m, lt->total);
424 }
425 
seq_stats(struct seq_file * m,struct lock_stat_data * data)426 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
427 {
428 	char name[39];
429 	struct lock_class *class;
430 	struct lock_class_stats *stats;
431 	int i, namelen;
432 
433 	class = data->class;
434 	stats = &data->stats;
435 
436 	namelen = 38;
437 	if (class->name_version > 1)
438 		namelen -= 2; /* XXX truncates versions > 9 */
439 	if (class->subclass)
440 		namelen -= 2;
441 
442 	if (!class->name) {
443 		char str[KSYM_NAME_LEN];
444 		const char *key_name;
445 
446 		key_name = __get_key_name(class->key, str);
447 		snprintf(name, namelen, "%s", key_name);
448 	} else {
449 		snprintf(name, namelen, "%s", class->name);
450 	}
451 	namelen = strlen(name);
452 	if (class->name_version > 1) {
453 		snprintf(name+namelen, 3, "#%d", class->name_version);
454 		namelen += 2;
455 	}
456 	if (class->subclass) {
457 		snprintf(name+namelen, 3, "/%d", class->subclass);
458 		namelen += 2;
459 	}
460 
461 	if (stats->write_holdtime.nr) {
462 		if (stats->read_holdtime.nr)
463 			seq_printf(m, "%38s-W:", name);
464 		else
465 			seq_printf(m, "%40s:", name);
466 
467 		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
468 		seq_lock_time(m, &stats->write_waittime);
469 		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
470 		seq_lock_time(m, &stats->write_holdtime);
471 		seq_puts(m, "\n");
472 	}
473 
474 	if (stats->read_holdtime.nr) {
475 		seq_printf(m, "%38s-R:", name);
476 		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
477 		seq_lock_time(m, &stats->read_waittime);
478 		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
479 		seq_lock_time(m, &stats->read_holdtime);
480 		seq_puts(m, "\n");
481 	}
482 
483 	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
484 		return;
485 
486 	if (stats->read_holdtime.nr)
487 		namelen += 2;
488 
489 	for (i = 0; i < LOCKSTAT_POINTS; i++) {
490 		char ip[32];
491 
492 		if (class->contention_point[i] == 0)
493 			break;
494 
495 		if (!i)
496 			seq_line(m, '-', 40-namelen, namelen);
497 
498 		snprintf(ip, sizeof(ip), "[<%p>]",
499 				(void *)class->contention_point[i]);
500 		seq_printf(m, "%40s %14lu %29s %pS\n",
501 			   name, stats->contention_point[i],
502 			   ip, (void *)class->contention_point[i]);
503 	}
504 	for (i = 0; i < LOCKSTAT_POINTS; i++) {
505 		char ip[32];
506 
507 		if (class->contending_point[i] == 0)
508 			break;
509 
510 		if (!i)
511 			seq_line(m, '-', 40-namelen, namelen);
512 
513 		snprintf(ip, sizeof(ip), "[<%p>]",
514 				(void *)class->contending_point[i]);
515 		seq_printf(m, "%40s %14lu %29s %pS\n",
516 			   name, stats->contending_point[i],
517 			   ip, (void *)class->contending_point[i]);
518 	}
519 	if (i) {
520 		seq_puts(m, "\n");
521 		seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
522 		seq_puts(m, "\n");
523 	}
524 }
525 
seq_header(struct seq_file * m)526 static void seq_header(struct seq_file *m)
527 {
528 	seq_printf(m, "lock_stat version 0.3\n");
529 
530 	if (unlikely(!debug_locks))
531 		seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
532 
533 	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
534 	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
535 			"%14s %14s\n",
536 			"class name",
537 			"con-bounces",
538 			"contentions",
539 			"waittime-min",
540 			"waittime-max",
541 			"waittime-total",
542 			"acq-bounces",
543 			"acquisitions",
544 			"holdtime-min",
545 			"holdtime-max",
546 			"holdtime-total");
547 	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
548 	seq_printf(m, "\n");
549 }
550 
ls_start(struct seq_file * m,loff_t * pos)551 static void *ls_start(struct seq_file *m, loff_t *pos)
552 {
553 	struct lock_stat_seq *data = m->private;
554 	struct lock_stat_data *iter;
555 
556 	if (*pos == 0)
557 		return SEQ_START_TOKEN;
558 
559 	iter = data->stats + (*pos - 1);
560 	if (iter >= data->iter_end)
561 		iter = NULL;
562 
563 	return iter;
564 }
565 
ls_next(struct seq_file * m,void * v,loff_t * pos)566 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
567 {
568 	(*pos)++;
569 	return ls_start(m, pos);
570 }
571 
ls_stop(struct seq_file * m,void * v)572 static void ls_stop(struct seq_file *m, void *v)
573 {
574 }
575 
ls_show(struct seq_file * m,void * v)576 static int ls_show(struct seq_file *m, void *v)
577 {
578 	if (v == SEQ_START_TOKEN)
579 		seq_header(m);
580 	else
581 		seq_stats(m, v);
582 
583 	return 0;
584 }
585 
586 static const struct seq_operations lockstat_ops = {
587 	.start	= ls_start,
588 	.next	= ls_next,
589 	.stop	= ls_stop,
590 	.show	= ls_show,
591 };
592 
lock_stat_open(struct inode * inode,struct file * file)593 static int lock_stat_open(struct inode *inode, struct file *file)
594 {
595 	int res;
596 	struct lock_class *class;
597 	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
598 
599 	if (!data)
600 		return -ENOMEM;
601 
602 	res = seq_open(file, &lockstat_ops);
603 	if (!res) {
604 		struct lock_stat_data *iter = data->stats;
605 		struct seq_file *m = file->private_data;
606 
607 		list_for_each_entry(class, &all_lock_classes, lock_entry) {
608 			iter->class = class;
609 			iter->stats = lock_stats(class);
610 			iter++;
611 		}
612 		data->iter_end = iter;
613 
614 		sort(data->stats, data->iter_end - data->stats,
615 				sizeof(struct lock_stat_data),
616 				lock_stat_cmp, NULL);
617 
618 		m->private = data;
619 	} else
620 		vfree(data);
621 
622 	return res;
623 }
624 
lock_stat_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)625 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
626 			       size_t count, loff_t *ppos)
627 {
628 	struct lock_class *class;
629 	char c;
630 
631 	if (count) {
632 		if (get_user(c, buf))
633 			return -EFAULT;
634 
635 		if (c != '0')
636 			return count;
637 
638 		list_for_each_entry(class, &all_lock_classes, lock_entry)
639 			clear_lock_stats(class);
640 	}
641 	return count;
642 }
643 
lock_stat_release(struct inode * inode,struct file * file)644 static int lock_stat_release(struct inode *inode, struct file *file)
645 {
646 	struct seq_file *seq = file->private_data;
647 
648 	vfree(seq->private);
649 	return seq_release(inode, file);
650 }
651 
652 static const struct file_operations proc_lock_stat_operations = {
653 	.open		= lock_stat_open,
654 	.write		= lock_stat_write,
655 	.read		= seq_read,
656 	.llseek		= seq_lseek,
657 	.release	= lock_stat_release,
658 };
659 #endif /* CONFIG_LOCK_STAT */
660 
lockdep_proc_init(void)661 static int __init lockdep_proc_init(void)
662 {
663 	proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
664 #ifdef CONFIG_PROVE_LOCKING
665 	proc_create("lockdep_chains", S_IRUSR, NULL,
666 		    &proc_lockdep_chains_operations);
667 #endif
668 	proc_create("lockdep_stats", S_IRUSR, NULL,
669 		    &proc_lockdep_stats_operations);
670 
671 #ifdef CONFIG_LOCK_STAT
672 	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
673 		    &proc_lock_stat_operations);
674 #endif
675 
676 	return 0;
677 }
678 
679 __initcall(lockdep_proc_init);
680 
681