xref: /openbmc/linux/tools/perf/util/map.c (revision 93d90ad7)
1 #include "symbol.h"
2 #include <errno.h>
3 #include <inttypes.h>
4 #include <limits.h>
5 #include <stdlib.h>
6 #include <string.h>
7 #include <stdio.h>
8 #include <unistd.h>
9 #include "map.h"
10 #include "thread.h"
11 #include "strlist.h"
12 #include "vdso.h"
13 #include "build-id.h"
14 #include "util.h"
15 #include "debug.h"
16 #include "machine.h"
17 #include <linux/string.h>
18 
19 const char *map_type__name[MAP__NR_TYPES] = {
20 	[MAP__FUNCTION] = "Functions",
21 	[MAP__VARIABLE] = "Variables",
22 };
23 
24 static inline int is_anon_memory(const char *filename)
25 {
26 	return !strcmp(filename, "//anon") ||
27 	       !strcmp(filename, "/dev/zero (deleted)") ||
28 	       !strcmp(filename, "/anon_hugepage (deleted)");
29 }
30 
31 static inline int is_no_dso_memory(const char *filename)
32 {
33 	return !strncmp(filename, "[stack", 6) ||
34 	       !strncmp(filename, "/SYSV",5)   ||
35 	       !strcmp(filename, "[heap]");
36 }
37 
38 static inline int is_android_lib(const char *filename)
39 {
40 	return !strncmp(filename, "/data/app-lib", 13) ||
41 	       !strncmp(filename, "/system/lib", 11);
42 }
43 
44 static inline bool replace_android_lib(const char *filename, char *newfilename)
45 {
46 	const char *libname;
47 	char *app_abi;
48 	size_t app_abi_length, new_length;
49 	size_t lib_length = 0;
50 
51 	libname  = strrchr(filename, '/');
52 	if (libname)
53 		lib_length = strlen(libname);
54 
55 	app_abi = getenv("APP_ABI");
56 	if (!app_abi)
57 		return false;
58 
59 	app_abi_length = strlen(app_abi);
60 
61 	if (!strncmp(filename, "/data/app-lib", 13)) {
62 		char *apk_path;
63 
64 		if (!app_abi_length)
65 			return false;
66 
67 		new_length = 7 + app_abi_length + lib_length;
68 
69 		apk_path = getenv("APK_PATH");
70 		if (apk_path) {
71 			new_length += strlen(apk_path) + 1;
72 			if (new_length > PATH_MAX)
73 				return false;
74 			snprintf(newfilename, new_length,
75 				 "%s/libs/%s/%s", apk_path, app_abi, libname);
76 		} else {
77 			if (new_length > PATH_MAX)
78 				return false;
79 			snprintf(newfilename, new_length,
80 				 "libs/%s/%s", app_abi, libname);
81 		}
82 		return true;
83 	}
84 
85 	if (!strncmp(filename, "/system/lib/", 11)) {
86 		char *ndk, *app;
87 		const char *arch;
88 		size_t ndk_length;
89 		size_t app_length;
90 
91 		ndk = getenv("NDK_ROOT");
92 		app = getenv("APP_PLATFORM");
93 
94 		if (!(ndk && app))
95 			return false;
96 
97 		ndk_length = strlen(ndk);
98 		app_length = strlen(app);
99 
100 		if (!(ndk_length && app_length && app_abi_length))
101 			return false;
102 
103 		arch = !strncmp(app_abi, "arm", 3) ? "arm" :
104 		       !strncmp(app_abi, "mips", 4) ? "mips" :
105 		       !strncmp(app_abi, "x86", 3) ? "x86" : NULL;
106 
107 		if (!arch)
108 			return false;
109 
110 		new_length = 27 + ndk_length +
111 			     app_length + lib_length
112 			   + strlen(arch);
113 
114 		if (new_length > PATH_MAX)
115 			return false;
116 		snprintf(newfilename, new_length,
117 			"%s/platforms/%s/arch-%s/usr/lib/%s",
118 			ndk, app, arch, libname);
119 
120 		return true;
121 	}
122 	return false;
123 }
124 
125 void map__init(struct map *map, enum map_type type,
126 	       u64 start, u64 end, u64 pgoff, struct dso *dso)
127 {
128 	map->type     = type;
129 	map->start    = start;
130 	map->end      = end;
131 	map->pgoff    = pgoff;
132 	map->reloc    = 0;
133 	map->dso      = dso;
134 	map->map_ip   = map__map_ip;
135 	map->unmap_ip = map__unmap_ip;
136 	RB_CLEAR_NODE(&map->rb_node);
137 	map->groups   = NULL;
138 	map->referenced = false;
139 	map->erange_warned = false;
140 }
141 
142 struct map *map__new(struct machine *machine, u64 start, u64 len,
143 		     u64 pgoff, u32 pid, u32 d_maj, u32 d_min, u64 ino,
144 		     u64 ino_gen, u32 prot, u32 flags, char *filename,
145 		     enum map_type type, struct thread *thread)
146 {
147 	struct map *map = malloc(sizeof(*map));
148 
149 	if (map != NULL) {
150 		char newfilename[PATH_MAX];
151 		struct dso *dso;
152 		int anon, no_dso, vdso, android;
153 
154 		android = is_android_lib(filename);
155 		anon = is_anon_memory(filename);
156 		vdso = is_vdso_map(filename);
157 		no_dso = is_no_dso_memory(filename);
158 
159 		map->maj = d_maj;
160 		map->min = d_min;
161 		map->ino = ino;
162 		map->ino_generation = ino_gen;
163 		map->prot = prot;
164 		map->flags = flags;
165 
166 		if ((anon || no_dso) && type == MAP__FUNCTION) {
167 			snprintf(newfilename, sizeof(newfilename), "/tmp/perf-%d.map", pid);
168 			filename = newfilename;
169 		}
170 
171 		if (android) {
172 			if (replace_android_lib(filename, newfilename))
173 				filename = newfilename;
174 		}
175 
176 		if (vdso) {
177 			pgoff = 0;
178 			dso = vdso__dso_findnew(machine, thread);
179 		} else
180 			dso = __dsos__findnew(&machine->user_dsos, filename);
181 
182 		if (dso == NULL)
183 			goto out_delete;
184 
185 		map__init(map, type, start, start + len, pgoff, dso);
186 
187 		if (anon || no_dso) {
188 			map->map_ip = map->unmap_ip = identity__map_ip;
189 
190 			/*
191 			 * Set memory without DSO as loaded. All map__find_*
192 			 * functions still return NULL, and we avoid the
193 			 * unnecessary map__load warning.
194 			 */
195 			if (type != MAP__FUNCTION)
196 				dso__set_loaded(dso, map->type);
197 		}
198 	}
199 	return map;
200 out_delete:
201 	free(map);
202 	return NULL;
203 }
204 
205 /*
206  * Constructor variant for modules (where we know from /proc/modules where
207  * they are loaded) and for vmlinux, where only after we load all the
208  * symbols we'll know where it starts and ends.
209  */
210 struct map *map__new2(u64 start, struct dso *dso, enum map_type type)
211 {
212 	struct map *map = calloc(1, (sizeof(*map) +
213 				     (dso->kernel ? sizeof(struct kmap) : 0)));
214 	if (map != NULL) {
215 		/*
216 		 * ->end will be filled after we load all the symbols
217 		 */
218 		map__init(map, type, start, 0, 0, dso);
219 	}
220 
221 	return map;
222 }
223 
224 void map__delete(struct map *map)
225 {
226 	free(map);
227 }
228 
229 void map__fixup_start(struct map *map)
230 {
231 	struct rb_root *symbols = &map->dso->symbols[map->type];
232 	struct rb_node *nd = rb_first(symbols);
233 	if (nd != NULL) {
234 		struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
235 		map->start = sym->start;
236 	}
237 }
238 
239 void map__fixup_end(struct map *map)
240 {
241 	struct rb_root *symbols = &map->dso->symbols[map->type];
242 	struct rb_node *nd = rb_last(symbols);
243 	if (nd != NULL) {
244 		struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
245 		map->end = sym->end;
246 	}
247 }
248 
249 #define DSO__DELETED "(deleted)"
250 
251 int map__load(struct map *map, symbol_filter_t filter)
252 {
253 	const char *name = map->dso->long_name;
254 	int nr;
255 
256 	if (dso__loaded(map->dso, map->type))
257 		return 0;
258 
259 	nr = dso__load(map->dso, map, filter);
260 	if (nr < 0) {
261 		if (map->dso->has_build_id) {
262 			char sbuild_id[BUILD_ID_SIZE * 2 + 1];
263 
264 			build_id__sprintf(map->dso->build_id,
265 					  sizeof(map->dso->build_id),
266 					  sbuild_id);
267 			pr_warning("%s with build id %s not found",
268 				   name, sbuild_id);
269 		} else
270 			pr_warning("Failed to open %s", name);
271 
272 		pr_warning(", continuing without symbols\n");
273 		return -1;
274 	} else if (nr == 0) {
275 #ifdef HAVE_LIBELF_SUPPORT
276 		const size_t len = strlen(name);
277 		const size_t real_len = len - sizeof(DSO__DELETED);
278 
279 		if (len > sizeof(DSO__DELETED) &&
280 		    strcmp(name + real_len + 1, DSO__DELETED) == 0) {
281 			pr_warning("%.*s was updated (is prelink enabled?). "
282 				"Restart the long running apps that use it!\n",
283 				   (int)real_len, name);
284 		} else {
285 			pr_warning("no symbols found in %s, maybe install "
286 				   "a debug package?\n", name);
287 		}
288 #endif
289 		return -1;
290 	}
291 
292 	return 0;
293 }
294 
295 struct symbol *map__find_symbol(struct map *map, u64 addr,
296 				symbol_filter_t filter)
297 {
298 	if (map__load(map, filter) < 0)
299 		return NULL;
300 
301 	return dso__find_symbol(map->dso, map->type, addr);
302 }
303 
304 struct symbol *map__find_symbol_by_name(struct map *map, const char *name,
305 					symbol_filter_t filter)
306 {
307 	if (map__load(map, filter) < 0)
308 		return NULL;
309 
310 	if (!dso__sorted_by_name(map->dso, map->type))
311 		dso__sort_by_name(map->dso, map->type);
312 
313 	return dso__find_symbol_by_name(map->dso, map->type, name);
314 }
315 
316 struct map *map__clone(struct map *map)
317 {
318 	return memdup(map, sizeof(*map));
319 }
320 
321 int map__overlap(struct map *l, struct map *r)
322 {
323 	if (l->start > r->start) {
324 		struct map *t = l;
325 		l = r;
326 		r = t;
327 	}
328 
329 	if (l->end > r->start)
330 		return 1;
331 
332 	return 0;
333 }
334 
335 size_t map__fprintf(struct map *map, FILE *fp)
336 {
337 	return fprintf(fp, " %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s\n",
338 		       map->start, map->end, map->pgoff, map->dso->name);
339 }
340 
341 size_t map__fprintf_dsoname(struct map *map, FILE *fp)
342 {
343 	const char *dsoname = "[unknown]";
344 
345 	if (map && map->dso && (map->dso->name || map->dso->long_name)) {
346 		if (symbol_conf.show_kernel_path && map->dso->long_name)
347 			dsoname = map->dso->long_name;
348 		else if (map->dso->name)
349 			dsoname = map->dso->name;
350 	}
351 
352 	return fprintf(fp, "%s", dsoname);
353 }
354 
355 int map__fprintf_srcline(struct map *map, u64 addr, const char *prefix,
356 			 FILE *fp)
357 {
358 	char *srcline;
359 	int ret = 0;
360 
361 	if (map && map->dso) {
362 		srcline = get_srcline(map->dso,
363 				      map__rip_2objdump(map, addr), NULL, true);
364 		if (srcline != SRCLINE_UNKNOWN)
365 			ret = fprintf(fp, "%s%s", prefix, srcline);
366 		free_srcline(srcline);
367 	}
368 	return ret;
369 }
370 
371 /**
372  * map__rip_2objdump - convert symbol start address to objdump address.
373  * @map: memory map
374  * @rip: symbol start address
375  *
376  * objdump wants/reports absolute IPs for ET_EXEC, and RIPs for ET_DYN.
377  * map->dso->adjust_symbols==1 for ET_EXEC-like cases except ET_REL which is
378  * relative to section start.
379  *
380  * Return: Address suitable for passing to "objdump --start-address="
381  */
382 u64 map__rip_2objdump(struct map *map, u64 rip)
383 {
384 	if (!map->dso->adjust_symbols)
385 		return rip;
386 
387 	if (map->dso->rel)
388 		return rip - map->pgoff;
389 
390 	return map->unmap_ip(map, rip) - map->reloc;
391 }
392 
393 /**
394  * map__objdump_2mem - convert objdump address to a memory address.
395  * @map: memory map
396  * @ip: objdump address
397  *
398  * Closely related to map__rip_2objdump(), this function takes an address from
399  * objdump and converts it to a memory address.  Note this assumes that @map
400  * contains the address.  To be sure the result is valid, check it forwards
401  * e.g. map__rip_2objdump(map->map_ip(map, map__objdump_2mem(map, ip))) == ip
402  *
403  * Return: Memory address.
404  */
405 u64 map__objdump_2mem(struct map *map, u64 ip)
406 {
407 	if (!map->dso->adjust_symbols)
408 		return map->unmap_ip(map, ip);
409 
410 	if (map->dso->rel)
411 		return map->unmap_ip(map, ip + map->pgoff);
412 
413 	return ip + map->reloc;
414 }
415 
416 void map_groups__init(struct map_groups *mg, struct machine *machine)
417 {
418 	int i;
419 	for (i = 0; i < MAP__NR_TYPES; ++i) {
420 		mg->maps[i] = RB_ROOT;
421 		INIT_LIST_HEAD(&mg->removed_maps[i]);
422 	}
423 	mg->machine = machine;
424 	mg->refcnt = 1;
425 }
426 
427 static void maps__delete(struct rb_root *maps)
428 {
429 	struct rb_node *next = rb_first(maps);
430 
431 	while (next) {
432 		struct map *pos = rb_entry(next, struct map, rb_node);
433 
434 		next = rb_next(&pos->rb_node);
435 		rb_erase(&pos->rb_node, maps);
436 		map__delete(pos);
437 	}
438 }
439 
440 static void maps__delete_removed(struct list_head *maps)
441 {
442 	struct map *pos, *n;
443 
444 	list_for_each_entry_safe(pos, n, maps, node) {
445 		list_del(&pos->node);
446 		map__delete(pos);
447 	}
448 }
449 
450 void map_groups__exit(struct map_groups *mg)
451 {
452 	int i;
453 
454 	for (i = 0; i < MAP__NR_TYPES; ++i) {
455 		maps__delete(&mg->maps[i]);
456 		maps__delete_removed(&mg->removed_maps[i]);
457 	}
458 }
459 
460 bool map_groups__empty(struct map_groups *mg)
461 {
462 	int i;
463 
464 	for (i = 0; i < MAP__NR_TYPES; ++i) {
465 		if (maps__first(&mg->maps[i]))
466 			return false;
467 		if (!list_empty(&mg->removed_maps[i]))
468 			return false;
469 	}
470 
471 	return true;
472 }
473 
474 struct map_groups *map_groups__new(struct machine *machine)
475 {
476 	struct map_groups *mg = malloc(sizeof(*mg));
477 
478 	if (mg != NULL)
479 		map_groups__init(mg, machine);
480 
481 	return mg;
482 }
483 
484 void map_groups__delete(struct map_groups *mg)
485 {
486 	map_groups__exit(mg);
487 	free(mg);
488 }
489 
490 void map_groups__put(struct map_groups *mg)
491 {
492 	if (--mg->refcnt == 0)
493 		map_groups__delete(mg);
494 }
495 
496 void map_groups__flush(struct map_groups *mg)
497 {
498 	int type;
499 
500 	for (type = 0; type < MAP__NR_TYPES; type++) {
501 		struct rb_root *root = &mg->maps[type];
502 		struct rb_node *next = rb_first(root);
503 
504 		while (next) {
505 			struct map *pos = rb_entry(next, struct map, rb_node);
506 			next = rb_next(&pos->rb_node);
507 			rb_erase(&pos->rb_node, root);
508 			/*
509 			 * We may have references to this map, for
510 			 * instance in some hist_entry instances, so
511 			 * just move them to a separate list.
512 			 */
513 			list_add_tail(&pos->node, &mg->removed_maps[pos->type]);
514 		}
515 	}
516 }
517 
518 struct symbol *map_groups__find_symbol(struct map_groups *mg,
519 				       enum map_type type, u64 addr,
520 				       struct map **mapp,
521 				       symbol_filter_t filter)
522 {
523 	struct map *map = map_groups__find(mg, type, addr);
524 
525 	/* Ensure map is loaded before using map->map_ip */
526 	if (map != NULL && map__load(map, filter) >= 0) {
527 		if (mapp != NULL)
528 			*mapp = map;
529 		return map__find_symbol(map, map->map_ip(map, addr), filter);
530 	}
531 
532 	return NULL;
533 }
534 
535 struct symbol *map_groups__find_symbol_by_name(struct map_groups *mg,
536 					       enum map_type type,
537 					       const char *name,
538 					       struct map **mapp,
539 					       symbol_filter_t filter)
540 {
541 	struct rb_node *nd;
542 
543 	for (nd = rb_first(&mg->maps[type]); nd; nd = rb_next(nd)) {
544 		struct map *pos = rb_entry(nd, struct map, rb_node);
545 		struct symbol *sym = map__find_symbol_by_name(pos, name, filter);
546 
547 		if (sym == NULL)
548 			continue;
549 		if (mapp != NULL)
550 			*mapp = pos;
551 		return sym;
552 	}
553 
554 	return NULL;
555 }
556 
557 int map_groups__find_ams(struct addr_map_symbol *ams, symbol_filter_t filter)
558 {
559 	if (ams->addr < ams->map->start || ams->addr >= ams->map->end) {
560 		if (ams->map->groups == NULL)
561 			return -1;
562 		ams->map = map_groups__find(ams->map->groups, ams->map->type,
563 					    ams->addr);
564 		if (ams->map == NULL)
565 			return -1;
566 	}
567 
568 	ams->al_addr = ams->map->map_ip(ams->map, ams->addr);
569 	ams->sym = map__find_symbol(ams->map, ams->al_addr, filter);
570 
571 	return ams->sym ? 0 : -1;
572 }
573 
574 size_t __map_groups__fprintf_maps(struct map_groups *mg, enum map_type type,
575 				  FILE *fp)
576 {
577 	size_t printed = fprintf(fp, "%s:\n", map_type__name[type]);
578 	struct rb_node *nd;
579 
580 	for (nd = rb_first(&mg->maps[type]); nd; nd = rb_next(nd)) {
581 		struct map *pos = rb_entry(nd, struct map, rb_node);
582 		printed += fprintf(fp, "Map:");
583 		printed += map__fprintf(pos, fp);
584 		if (verbose > 2) {
585 			printed += dso__fprintf(pos->dso, type, fp);
586 			printed += fprintf(fp, "--\n");
587 		}
588 	}
589 
590 	return printed;
591 }
592 
593 static size_t map_groups__fprintf_maps(struct map_groups *mg, FILE *fp)
594 {
595 	size_t printed = 0, i;
596 	for (i = 0; i < MAP__NR_TYPES; ++i)
597 		printed += __map_groups__fprintf_maps(mg, i, fp);
598 	return printed;
599 }
600 
601 static size_t __map_groups__fprintf_removed_maps(struct map_groups *mg,
602 						 enum map_type type, FILE *fp)
603 {
604 	struct map *pos;
605 	size_t printed = 0;
606 
607 	list_for_each_entry(pos, &mg->removed_maps[type], node) {
608 		printed += fprintf(fp, "Map:");
609 		printed += map__fprintf(pos, fp);
610 		if (verbose > 1) {
611 			printed += dso__fprintf(pos->dso, type, fp);
612 			printed += fprintf(fp, "--\n");
613 		}
614 	}
615 	return printed;
616 }
617 
618 static size_t map_groups__fprintf_removed_maps(struct map_groups *mg,
619 					       FILE *fp)
620 {
621 	size_t printed = 0, i;
622 	for (i = 0; i < MAP__NR_TYPES; ++i)
623 		printed += __map_groups__fprintf_removed_maps(mg, i, fp);
624 	return printed;
625 }
626 
627 size_t map_groups__fprintf(struct map_groups *mg, FILE *fp)
628 {
629 	size_t printed = map_groups__fprintf_maps(mg, fp);
630 	printed += fprintf(fp, "Removed maps:\n");
631 	return printed + map_groups__fprintf_removed_maps(mg, fp);
632 }
633 
634 int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map,
635 				   FILE *fp)
636 {
637 	struct rb_root *root = &mg->maps[map->type];
638 	struct rb_node *next = rb_first(root);
639 	int err = 0;
640 
641 	while (next) {
642 		struct map *pos = rb_entry(next, struct map, rb_node);
643 		next = rb_next(&pos->rb_node);
644 
645 		if (!map__overlap(pos, map))
646 			continue;
647 
648 		if (verbose >= 2) {
649 			fputs("overlapping maps:\n", fp);
650 			map__fprintf(map, fp);
651 			map__fprintf(pos, fp);
652 		}
653 
654 		rb_erase(&pos->rb_node, root);
655 		/*
656 		 * Now check if we need to create new maps for areas not
657 		 * overlapped by the new map:
658 		 */
659 		if (map->start > pos->start) {
660 			struct map *before = map__clone(pos);
661 
662 			if (before == NULL) {
663 				err = -ENOMEM;
664 				goto move_map;
665 			}
666 
667 			before->end = map->start;
668 			map_groups__insert(mg, before);
669 			if (verbose >= 2)
670 				map__fprintf(before, fp);
671 		}
672 
673 		if (map->end < pos->end) {
674 			struct map *after = map__clone(pos);
675 
676 			if (after == NULL) {
677 				err = -ENOMEM;
678 				goto move_map;
679 			}
680 
681 			after->start = map->end;
682 			map_groups__insert(mg, after);
683 			if (verbose >= 2)
684 				map__fprintf(after, fp);
685 		}
686 move_map:
687 		/*
688 		 * If we have references, just move them to a separate list.
689 		 */
690 		if (pos->referenced)
691 			list_add_tail(&pos->node, &mg->removed_maps[map->type]);
692 		else
693 			map__delete(pos);
694 
695 		if (err)
696 			return err;
697 	}
698 
699 	return 0;
700 }
701 
702 /*
703  * XXX This should not really _copy_ te maps, but refcount them.
704  */
705 int map_groups__clone(struct map_groups *mg,
706 		      struct map_groups *parent, enum map_type type)
707 {
708 	struct rb_node *nd;
709 	for (nd = rb_first(&parent->maps[type]); nd; nd = rb_next(nd)) {
710 		struct map *map = rb_entry(nd, struct map, rb_node);
711 		struct map *new = map__clone(map);
712 		if (new == NULL)
713 			return -ENOMEM;
714 		map_groups__insert(mg, new);
715 	}
716 	return 0;
717 }
718 
719 void maps__insert(struct rb_root *maps, struct map *map)
720 {
721 	struct rb_node **p = &maps->rb_node;
722 	struct rb_node *parent = NULL;
723 	const u64 ip = map->start;
724 	struct map *m;
725 
726 	while (*p != NULL) {
727 		parent = *p;
728 		m = rb_entry(parent, struct map, rb_node);
729 		if (ip < m->start)
730 			p = &(*p)->rb_left;
731 		else
732 			p = &(*p)->rb_right;
733 	}
734 
735 	rb_link_node(&map->rb_node, parent, p);
736 	rb_insert_color(&map->rb_node, maps);
737 }
738 
739 void maps__remove(struct rb_root *maps, struct map *map)
740 {
741 	rb_erase(&map->rb_node, maps);
742 }
743 
744 struct map *maps__find(struct rb_root *maps, u64 ip)
745 {
746 	struct rb_node **p = &maps->rb_node;
747 	struct rb_node *parent = NULL;
748 	struct map *m;
749 
750 	while (*p != NULL) {
751 		parent = *p;
752 		m = rb_entry(parent, struct map, rb_node);
753 		if (ip < m->start)
754 			p = &(*p)->rb_left;
755 		else if (ip >= m->end)
756 			p = &(*p)->rb_right;
757 		else
758 			return m;
759 	}
760 
761 	return NULL;
762 }
763 
764 struct map *maps__first(struct rb_root *maps)
765 {
766 	struct rb_node *first = rb_first(maps);
767 
768 	if (first)
769 		return rb_entry(first, struct map, rb_node);
770 	return NULL;
771 }
772 
773 struct map *maps__next(struct map *map)
774 {
775 	struct rb_node *next = rb_next(&map->rb_node);
776 
777 	if (next)
778 		return rb_entry(next, struct map, rb_node);
779 	return NULL;
780 }
781