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1 /*
2  * kernel/lockdep_proc.c
3  *
4  * Runtime locking correctness validator
5  *
6  * Started by Ingo Molnar:
7  *
8  *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
10  *
11  * Code for /proc/lockdep and /proc/lockdep_stats:
12  *
13  */
14 #include <linux/module.h>
15 #include <linux/proc_fs.h>
16 #include <linux/seq_file.h>
17 #include <linux/kallsyms.h>
18 #include <linux/debug_locks.h>
19 #include <linux/vmalloc.h>
20 #include <linux/sort.h>
21 #include <asm/uaccess.h>
22 #include <asm/div64.h>
23 
24 #include "lockdep_internals.h"
25 
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 	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 
l_start(struct seq_file * m,loff_t * pos)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 
l_stop(struct seq_file * m,void * v)62 static void l_stop(struct seq_file *m, void *v)
63 {
64 }
65 
print_name(struct seq_file * m,struct lock_class * class)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 
l_show(struct seq_file * m,void * v)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 
lockdep_open(struct inode * inode,struct file * file)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
lc_next(struct seq_file * m,void * v,loff_t * pos)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 
lc_start(struct seq_file * m,loff_t * pos)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 
lc_stop(struct seq_file * m,void * v)183 static void lc_stop(struct seq_file *m, void *v)
184 {
185 }
186 
lc_show(struct seq_file * m,void * v)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 
lockdep_chains_open(struct inode * inode,struct file * file)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 
lockdep_stats_debug_show(struct seq_file * m)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 
lockdep_stats_show(struct seq_file * m,void * v)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 
lockdep_stats_open(struct inode * inode,struct file * file)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  */
lock_stat_cmp(const void * l,const void * r)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 
seq_line(struct seq_file * m,char c,int offset,int length)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 
snprint_time(char * buf,size_t bufsiz,s64 nr)471 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
472 {
473 	s64 div;
474 	s32 rem;
475 
476 	nr += 5; /* for display rounding */
477 	div = div_s64_rem(nr, 1000, &rem);
478 	snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
479 }
480 
seq_time(struct seq_file * m,s64 time)481 static void seq_time(struct seq_file *m, s64 time)
482 {
483 	char num[15];
484 
485 	snprint_time(num, sizeof(num), time);
486 	seq_printf(m, " %14s", num);
487 }
488 
seq_lock_time(struct seq_file * m,struct lock_time * lt)489 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
490 {
491 	seq_printf(m, "%14lu", lt->nr);
492 	seq_time(m, lt->min);
493 	seq_time(m, lt->max);
494 	seq_time(m, lt->total);
495 }
496 
seq_stats(struct seq_file * m,struct lock_stat_data * data)497 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
498 {
499 	char name[39];
500 	struct lock_class *class;
501 	struct lock_class_stats *stats;
502 	int i, namelen;
503 
504 	class = data->class;
505 	stats = &data->stats;
506 
507 	namelen = 38;
508 	if (class->name_version > 1)
509 		namelen -= 2; /* XXX truncates versions > 9 */
510 	if (class->subclass)
511 		namelen -= 2;
512 
513 	if (!class->name) {
514 		char str[KSYM_NAME_LEN];
515 		const char *key_name;
516 
517 		key_name = __get_key_name(class->key, str);
518 		snprintf(name, namelen, "%s", key_name);
519 	} else {
520 		snprintf(name, namelen, "%s", class->name);
521 	}
522 	namelen = strlen(name);
523 	if (class->name_version > 1) {
524 		snprintf(name+namelen, 3, "#%d", class->name_version);
525 		namelen += 2;
526 	}
527 	if (class->subclass) {
528 		snprintf(name+namelen, 3, "/%d", class->subclass);
529 		namelen += 2;
530 	}
531 
532 	if (stats->write_holdtime.nr) {
533 		if (stats->read_holdtime.nr)
534 			seq_printf(m, "%38s-W:", name);
535 		else
536 			seq_printf(m, "%40s:", name);
537 
538 		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
539 		seq_lock_time(m, &stats->write_waittime);
540 		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
541 		seq_lock_time(m, &stats->write_holdtime);
542 		seq_puts(m, "\n");
543 	}
544 
545 	if (stats->read_holdtime.nr) {
546 		seq_printf(m, "%38s-R:", name);
547 		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
548 		seq_lock_time(m, &stats->read_waittime);
549 		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
550 		seq_lock_time(m, &stats->read_holdtime);
551 		seq_puts(m, "\n");
552 	}
553 
554 	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
555 		return;
556 
557 	if (stats->read_holdtime.nr)
558 		namelen += 2;
559 
560 	for (i = 0; i < LOCKSTAT_POINTS; i++) {
561 		char sym[KSYM_SYMBOL_LEN];
562 		char ip[32];
563 
564 		if (class->contention_point[i] == 0)
565 			break;
566 
567 		if (!i)
568 			seq_line(m, '-', 40-namelen, namelen);
569 
570 		sprint_symbol(sym, class->contention_point[i]);
571 		snprintf(ip, sizeof(ip), "[<%p>]",
572 				(void *)class->contention_point[i]);
573 		seq_printf(m, "%40s %14lu %29s %s\n", name,
574 				stats->contention_point[i],
575 				ip, sym);
576 	}
577 	for (i = 0; i < LOCKSTAT_POINTS; i++) {
578 		char sym[KSYM_SYMBOL_LEN];
579 		char ip[32];
580 
581 		if (class->contending_point[i] == 0)
582 			break;
583 
584 		if (!i)
585 			seq_line(m, '-', 40-namelen, namelen);
586 
587 		sprint_symbol(sym, class->contending_point[i]);
588 		snprintf(ip, sizeof(ip), "[<%p>]",
589 				(void *)class->contending_point[i]);
590 		seq_printf(m, "%40s %14lu %29s %s\n", name,
591 				stats->contending_point[i],
592 				ip, sym);
593 	}
594 	if (i) {
595 		seq_puts(m, "\n");
596 		seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
597 		seq_puts(m, "\n");
598 	}
599 }
600 
seq_header(struct seq_file * m)601 static void seq_header(struct seq_file *m)
602 {
603 	seq_printf(m, "lock_stat version 0.3\n");
604 	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
605 	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
606 			"%14s %14s\n",
607 			"class name",
608 			"con-bounces",
609 			"contentions",
610 			"waittime-min",
611 			"waittime-max",
612 			"waittime-total",
613 			"acq-bounces",
614 			"acquisitions",
615 			"holdtime-min",
616 			"holdtime-max",
617 			"holdtime-total");
618 	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
619 	seq_printf(m, "\n");
620 }
621 
ls_start(struct seq_file * m,loff_t * pos)622 static void *ls_start(struct seq_file *m, loff_t *pos)
623 {
624 	struct lock_stat_seq *data = m->private;
625 
626 	if (*pos == 0)
627 		return SEQ_START_TOKEN;
628 
629 	data->iter = data->stats + *pos;
630 	if (data->iter >= data->iter_end)
631 		data->iter = NULL;
632 
633 	return data->iter;
634 }
635 
ls_next(struct seq_file * m,void * v,loff_t * pos)636 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
637 {
638 	struct lock_stat_seq *data = m->private;
639 
640 	(*pos)++;
641 
642 	if (v == SEQ_START_TOKEN)
643 		data->iter = data->stats;
644 	else {
645 		data->iter = v;
646 		data->iter++;
647 	}
648 
649 	if (data->iter == data->iter_end)
650 		data->iter = NULL;
651 
652 	return data->iter;
653 }
654 
ls_stop(struct seq_file * m,void * v)655 static void ls_stop(struct seq_file *m, void *v)
656 {
657 }
658 
ls_show(struct seq_file * m,void * v)659 static int ls_show(struct seq_file *m, void *v)
660 {
661 	if (v == SEQ_START_TOKEN)
662 		seq_header(m);
663 	else
664 		seq_stats(m, v);
665 
666 	return 0;
667 }
668 
669 static struct seq_operations lockstat_ops = {
670 	.start	= ls_start,
671 	.next	= ls_next,
672 	.stop	= ls_stop,
673 	.show	= ls_show,
674 };
675 
lock_stat_open(struct inode * inode,struct file * file)676 static int lock_stat_open(struct inode *inode, struct file *file)
677 {
678 	int res;
679 	struct lock_class *class;
680 	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
681 
682 	if (!data)
683 		return -ENOMEM;
684 
685 	res = seq_open(file, &lockstat_ops);
686 	if (!res) {
687 		struct lock_stat_data *iter = data->stats;
688 		struct seq_file *m = file->private_data;
689 
690 		data->iter = iter;
691 		list_for_each_entry(class, &all_lock_classes, lock_entry) {
692 			iter->class = class;
693 			iter->stats = lock_stats(class);
694 			iter++;
695 		}
696 		data->iter_end = iter;
697 
698 		sort(data->stats, data->iter_end - data->iter,
699 				sizeof(struct lock_stat_data),
700 				lock_stat_cmp, NULL);
701 
702 		m->private = data;
703 	} else
704 		vfree(data);
705 
706 	return res;
707 }
708 
lock_stat_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)709 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
710 			       size_t count, loff_t *ppos)
711 {
712 	struct lock_class *class;
713 	char c;
714 
715 	if (count) {
716 		if (get_user(c, buf))
717 			return -EFAULT;
718 
719 		if (c != '0')
720 			return count;
721 
722 		list_for_each_entry(class, &all_lock_classes, lock_entry)
723 			clear_lock_stats(class);
724 	}
725 	return count;
726 }
727 
lock_stat_release(struct inode * inode,struct file * file)728 static int lock_stat_release(struct inode *inode, struct file *file)
729 {
730 	struct seq_file *seq = file->private_data;
731 
732 	vfree(seq->private);
733 	seq->private = NULL;
734 	return seq_release(inode, file);
735 }
736 
737 static const struct file_operations proc_lock_stat_operations = {
738 	.open		= lock_stat_open,
739 	.write		= lock_stat_write,
740 	.read		= seq_read,
741 	.llseek		= seq_lseek,
742 	.release	= lock_stat_release,
743 };
744 #endif /* CONFIG_LOCK_STAT */
745 
lockdep_proc_init(void)746 static int __init lockdep_proc_init(void)
747 {
748 	proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
749 #ifdef CONFIG_PROVE_LOCKING
750 	proc_create("lockdep_chains", S_IRUSR, NULL,
751 		    &proc_lockdep_chains_operations);
752 #endif
753 	proc_create("lockdep_stats", S_IRUSR, NULL,
754 		    &proc_lockdep_stats_operations);
755 
756 #ifdef CONFIG_LOCK_STAT
757 	proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
758 #endif
759 
760 	return 0;
761 }
762 
763 __initcall(lockdep_proc_init);
764 
765