summaryrefslogtreecommitdiffstats
path: root/drivers/base/devres.c
blob: e038e2b3b7ea4a7d53d2d7c189f9dbac269ea228 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/base/devres.c - device resource management
 *
 * Copyright (c) 2006  SUSE Linux Products GmbH
 * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/percpu.h>

#include <asm/sections.h>

#include "base.h"

struct devres_node {
	struct list_head		entry;
	dr_release_t			release;
#ifdef CONFIG_DEBUG_DEVRES
	const char			*name;
	size_t				size;
#endif
};

struct devres {
	struct devres_node		node;
	/*
	 * Some archs want to perform DMA into kmalloc caches
	 * and need a guaranteed alignment larger than
	 * the alignment of a 64-bit integer.
	 * Thus we use ARCH_KMALLOC_MINALIGN here and get exactly the same
	 * buffer alignment as if it was allocated by plain kmalloc().
	 */
	u8 __aligned(ARCH_KMALLOC_MINALIGN) data[];
};

struct devres_group {
	struct devres_node		node[2];
	void				*id;
	int				color;
	/* -- 8 pointers */
};

#ifdef CONFIG_DEBUG_DEVRES
static int log_devres = 0;
module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);

static void set_node_dbginfo(struct devres_node *node, const char *name,
			     size_t size)
{
	node->name = name;
	node->size = size;
}

static void devres_log(struct device *dev, struct devres_node *node,
		       const char *op)
{
	if (unlikely(log_devres))
		dev_err(dev, "DEVRES %3s %p %s (%lu bytes)\n",
			op, node, node->name, (unsigned long)node->size);
}
#else /* CONFIG_DEBUG_DEVRES */
#define set_node_dbginfo(node, n, s)	do {} while (0)
#define devres_log(dev, node, op)	do {} while (0)
#endif /* CONFIG_DEBUG_DEVRES */

/*
 * Release functions for devres group.  These callbacks are used only
 * for identification.
 */
static void group_open_release(struct device *dev, void *res)
{
	/* noop */
}

static void group_close_release(struct device *dev, void *res)
{
	/* noop */
}

static struct devres_group * node_to_group(struct devres_node *node)
{
	if (node->release == &group_open_release)
		return container_of(node, struct devres_group, node[0]);
	if (node->release == &group_close_release)
		return container_of(node, struct devres_group, node[1]);
	return NULL;
}

static __always_inline struct devres * alloc_dr(dr_release_t release,
						size_t size, gfp_t gfp, int nid)
{
	size_t tot_size;
	struct devres *dr;

	/* We must catch any near-SIZE_MAX cases that could overflow. */
	if (unlikely(check_add_overflow(sizeof(struct devres), size,
					&tot_size)))
		return NULL;

	dr = kmalloc_node_track_caller(tot_size, gfp, nid);
	if (unlikely(!dr))
		return NULL;

	memset(dr, 0, offsetof(struct devres, data));

	INIT_LIST_HEAD(&dr->node.entry);
	dr->node.release = release;
	return dr;
}

static void add_dr(struct device *dev, struct devres_node *node)
{
	devres_log(dev, node, "ADD");
	BUG_ON(!list_empty(&node->entry));
	list_add_tail(&node->entry, &dev->devres_head);
}

#ifdef CONFIG_DEBUG_DEVRES
void * __devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp, int nid,
		      const char *name)
{
	struct devres *dr;

	dr = alloc_dr(release, size, gfp | __GFP_ZERO, nid);
	if (unlikely(!dr))
		return NULL;
	set_node_dbginfo(&dr->node, name, size);
	return dr->data;
}
EXPORT_SYMBOL_GPL(__devres_alloc_node);
#else
/**
 * devres_alloc - Allocate device resource data
 * @release: Release function devres will be associated with
 * @size: Allocation size
 * @gfp: Allocation flags
 * @nid: NUMA node
 *
 * Allocate devres of @size bytes.  The allocated area is zeroed, then
 * associated with @release.  The returned pointer can be passed to
 * other devres_*() functions.
 *
 * RETURNS:
 * Pointer to allocated devres on success, NULL on failure.
 */
void * devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp, int nid)
{
	struct devres *dr;

	dr = alloc_dr(release, size, gfp | __GFP_ZERO, nid);
	if (unlikely(!dr))
		return NULL;
	return dr->data;
}
EXPORT_SYMBOL_GPL(devres_alloc_node);
#endif

/**
 * devres_for_each_res - Resource iterator
 * @dev: Device to iterate resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 * @fn: Function to be called for each matched resource.
 * @data: Data for @fn, the 3rd parameter of @fn
 *
 * Call @fn for each devres of @dev which is associated with @release
 * and for which @match returns 1.
 *
 * RETURNS:
 * 	void
 */
void devres_for_each_res(struct device *dev, dr_release_t release,
			dr_match_t match, void *match_data,
			void (*fn)(struct device *, void *, void *),
			void *data)
{
	struct devres_node *node;
	struct devres_node *tmp;
	unsigned long flags;

	if (!fn)
		return;

	spin_lock_irqsave(&dev->devres_lock, flags);
	list_for_each_entry_safe_reverse(node, tmp,
			&dev->devres_head, entry) {
		struct devres *dr = container_of(node, struct devres, node);

		if (node->release != release)
			continue;
		if (match && !match(dev, dr->data, match_data))
			continue;
		fn(dev, dr->data, data);
	}
	spin_unlock_irqrestore(&dev->devres_lock, flags);
}
EXPORT_SYMBOL_GPL(devres_for_each_res);

/**
 * devres_free - Free device resource data
 * @res: Pointer to devres data to free
 *
 * Free devres created with devres_alloc().
 */
void devres_free(void *res)
{
	if (res) {
		struct devres *dr = container_of(res, struct devres, data);

		BUG_ON(!list_empty(&dr->node.entry));
		kfree(dr);
	}
}
EXPORT_SYMBOL_GPL(devres_free);

/**
 * devres_add - Register device resource
 * @dev: Device to add resource to
 * @res: Resource to register
 *
 * Register devres @res to @dev.  @res should have been allocated
 * using devres_alloc().  On driver detach, the associated release
 * function will be invoked and devres will be freed automatically.
 */
void devres_add(struct device *dev, void *res)
{
	struct devres *dr = container_of(res, struct devres, data);
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	add_dr(dev, &dr->node);
	spin_unlock_irqrestore(&dev->devres_lock, flags);
}
EXPORT_SYMBOL_GPL(devres_add);

static struct devres *find_dr(struct device *dev, dr_release_t release,
			      dr_match_t match, void *match_data)
{
	struct devres_node *node;

	list_for_each_entry_reverse(node, &dev->devres_head, entry) {
		struct devres *dr = container_of(node, struct devres, node);

		if (node->release != release)
			continue;
		if (match && !match(dev, dr->data, match_data))
			continue;
		return dr;
	}

	return NULL;
}

/**
 * devres_find - Find device resource
 * @dev: Device to lookup resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev which is associated with @release
 * and for which @match returns 1.  If @match is NULL, it's considered
 * to match all.
 *
 * RETURNS:
 * Pointer to found devres, NULL if not found.
 */
void * devres_find(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	struct devres *dr;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	dr = find_dr(dev, release, match, match_data);
	spin_unlock_irqrestore(&dev->devres_lock, flags);

	if (dr)
		return dr->data;
	return NULL;
}
EXPORT_SYMBOL_GPL(devres_find);

/**
 * devres_get - Find devres, if non-existent, add one atomically
 * @dev: Device to lookup or add devres for
 * @new_res: Pointer to new initialized devres to add if not found
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev which has the same release function
 * as @new_res and for which @match return 1.  If found, @new_res is
 * freed; otherwise, @new_res is added atomically.
 *
 * RETURNS:
 * Pointer to found or added devres.
 */
void * devres_get(struct device *dev, void *new_res,
		  dr_match_t match, void *match_data)
{
	struct devres *new_dr = container_of(new_res, struct devres, data);
	struct devres *dr;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	dr = find_dr(dev, new_dr->node.release, match, match_data);
	if (!dr) {
		add_dr(dev, &new_dr->node);
		dr = new_dr;
		new_res = NULL;
	}
	spin_unlock_irqrestore(&dev->devres_lock, flags);
	devres_free(new_res);

	return dr->data;
}
EXPORT_SYMBOL_GPL(devres_get);

/**
 * devres_remove - Find a device resource and remove it
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically and
 * returned.
 *
 * RETURNS:
 * Pointer to removed devres on success, NULL if not found.
 */
void * devres_remove(struct device *dev, dr_release_t release,
		     dr_match_t match, void *match_data)
{
	struct devres *dr;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);
	dr = find_dr(dev, release, match, match_data);
	if (dr) {
		list_del_init(&dr->node.entry);
		devres_log(dev, &dr->node, "REM");
	}
	spin_unlock_irqrestore(&dev->devres_lock, flags);

	if (dr)
		return dr->data;
	return NULL;
}
EXPORT_SYMBOL_GPL(devres_remove);

/**
 * devres_destroy - Find a device resource and destroy it
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically and freed.
 *
 * Note that the release function for the resource will not be called,
 * only the devres-allocated data will be freed.  The caller becomes
 * responsible for freeing any other data.
 *
 * RETURNS:
 * 0 if devres is found and freed, -ENOENT if not found.
 */
int devres_destroy(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	void *res;

	res = devres_remove(dev, release, match, match_data);
	if (unlikely(!res))
		return -ENOENT;

	devres_free(res);
	return 0;
}
EXPORT_SYMBOL_GPL(devres_destroy);


/**
 * devres_release - Find a device resource and destroy it, calling release
 * @dev: Device to find resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 *
 * Find the latest devres of @dev associated with @release and for
 * which @match returns 1.  If @match is NULL, it's considered to
 * match all.  If found, the resource is removed atomically, the
 * release function called and the resource freed.
 *
 * RETURNS:
 * 0 if devres is found and freed, -ENOENT if not found.
 */
int devres_release(struct device *dev, dr_release_t release,
		   dr_match_t match, void *match_data)
{
	void *res;

	res = devres_remove(dev, release, match, match_data);
	if (unlikely(!res))
		return -ENOENT;

	(*release)(dev, res);
	devres_free(res);
	return 0;
}
EXPORT_SYMBOL_GPL(devres_release);

static int remove_nodes(struct device *dev,
			struct list_head *first, struct list_head *end,
			struct list_head *todo)
{
	int cnt = 0, nr_groups = 0;
	struct list_head *cur;

	/* First pass - move normal devres entries to @todo and clear
	 * devres_group colors.
	 */
	cur = first;
	while (cur != end) {
		struct devres_node *node;
		struct devres_group *grp;

		node = list_entry(cur, struct devres_node, entry);
		cur = cur->next;

		grp = node_to_group(node);
		if (grp) {
			/* clear color of group markers in the first pass */
			grp->color = 0;
			nr_groups++;
		} else {
			/* regular devres entry */
			if (&node->entry == first)
				first = first->next;
			list_move_tail(&node->entry, todo);
			cnt++;
		}
	}

	if (!nr_groups)
		return cnt;

	/* Second pass - Scan groups and color them.  A group gets
	 * color value of two iff the group is wholly contained in
	 * [cur, end).  That is, for a closed group, both opening and
	 * closing markers should be in the range, while just the
	 * opening marker is enough for an open group.
	 */
	cur = first;
	while (cur != end) {
		struct devres_node *node;
		struct devres_group *grp;

		node = list_entry(cur, struct devres_node, entry);
		cur = cur->next;

		grp = node_to_group(node);
		BUG_ON(!grp || list_empty(&grp->node[0].entry));

		grp->color++;
		if (list_empty(&grp->node[1].entry))
			grp->color++;

		BUG_ON(grp->color <= 0 || grp->color > 2);
		if (grp->color == 2) {
			/* No need to update cur or end.  The removed
			 * nodes are always before both.
			 */
			list_move_tail(&grp->node[0].entry, todo);
			list_del_init(&grp->node[1].entry);
		}
	}

	return cnt;
}

static int release_nodes(struct device *dev, struct list_head *first,
			 struct list_head *end, unsigned long flags)
	__releases(&dev->devres_lock)
{
	LIST_HEAD(todo);
	int cnt;
	struct devres *dr, *tmp;

	cnt = remove_nodes(dev, first, end, &todo);

	spin_unlock_irqrestore(&dev->devres_lock, flags);

	/* Release.  Note that both devres and devres_group are
	 * handled as devres in the following loop.  This is safe.
	 */
	list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
		devres_log(dev, &dr->node, "REL");
		dr->node.release(dev, dr->data);
		kfree(dr);
	}

	return cnt;
}

/**
 * devres_release_all - Release all managed resources
 * @dev: Device to release resources for
 *
 * Release all resources associated with @dev.  This function is
 * called on driver detach.
 */
int devres_release_all(struct device *dev)
{
	unsigned long flags;

	/* Looks like an uninitialized device structure */
	if (WARN_ON(dev->devres_head.next == NULL))
		return -ENODEV;
	spin_lock_irqsave(&dev->devres_lock, flags);
	return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
			     flags);
}

/**
 * devres_open_group - Open a new devres group
 * @dev: Device to open devres group for
 * @id: Separator ID
 * @gfp: Allocation flags
 *
 * Open a new devres group for @dev with @id.  For @id, using a
 * pointer to an object which won't be used for another group is
 * recommended.  If @id is NULL, address-wise unique ID is created.
 *
 * RETURNS:
 * ID of the new group, NULL on failure.
 */
void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
{
	struct devres_group *grp;
	unsigned long flags;

	grp = kmalloc(sizeof(*grp), gfp);
	if (unlikely(!grp))
		return NULL;

	grp->node[0].release = &group_open_release;
	grp->node[1].release = &group_close_release;
	INIT_LIST_HEAD(&grp->node[0].entry);
	INIT_LIST_HEAD(&grp->node[1].entry);
	set_node_dbginfo(&grp->node[0], "grp<", 0);
	set_node_dbginfo(&grp->node[1], "grp>", 0);
	grp->id = grp;
	if (id)
		grp->id = id;

	spin_lock_irqsave(&dev->devres_lock, flags);
	add_dr(dev, &grp->node[0]);
	spin_unlock_irqrestore(&dev->devres_lock, flags);
	return grp->id;
}
EXPORT_SYMBOL_GPL(devres_open_group);

/* Find devres group with ID @id.  If @id is NULL, look for the latest. */
static struct devres_group * find_group(struct device *dev, void *id)
{
	struct devres_node *node;

	list_for_each_entry_reverse(node, &dev->devres_head, entry) {
		struct devres_group *grp;

		if (node->release != &group_open_release)
			continue;

		grp = container_of(node, struct devres_group, node[0]);

		if (id) {
			if (grp->id == id)
				return grp;
		} else if (list_empty(&grp->node[1].entry))
			return grp;
	}

	return NULL;
}

/**
 * devres_close_group - Close a devres group
 * @dev: Device to close devres group for
 * @id: ID of target group, can be NULL
 *
 * Close the group identified by @id.  If @id is NULL, the latest open
 * group is selected.
 */
void devres_close_group(struct device *dev, void *id)
{
	struct devres_group *grp;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);

	grp = find_group(dev, id);
	if (grp)
		add_dr(dev, &grp->node[1]);
	else
		WARN_ON(1);

	spin_unlock_irqrestore(&dev->devres_lock, flags);
}
EXPORT_SYMBOL_GPL(devres_close_group);

/**
 * devres_remove_group - Remove a devres group
 * @dev: Device to remove group for
 * @id: ID of target group, can be NULL
 *
 * Remove the group identified by @id.  If @id is NULL, the latest
 * open group is selected.  Note that removing a group doesn't affect
 * any other resources.
 */
void devres_remove_group(struct device *dev, void *id)
{
	struct devres_group *grp;
	unsigned long flags;

	spin_lock_irqsave(&dev->devres_lock, flags);

	grp = find_group(dev, id);
	if (grp) {
		list_del_init(&grp->node[0].entry);
		list_del_init(&grp->node[1].entry);
		devres_log(dev, &grp->node[0], "REM");
	} else
		WARN_ON(1);

	spin_unlock_irqrestore(&dev->devres_lock, flags);

	kfree(grp);
}
EXPORT_SYMBOL_GPL(devres_remove_group);

/**
 * devres_release_group - Release resources in a devres group
 * @dev: Device to release group for
 * @id: ID of target group, can be NULL
 *
 * Release all resources in the group identified by @id.  If @id is
 * NULL, the latest open group is selected.  The selected group and
 * groups properly nested inside the selected group are removed.
 *
 * RETURNS:
 * The number of released non-group resources.
 */
int devres_release_group(struct device *dev, void *id)
{
	struct devres_group *grp;
	unsigned long flags;
	int cnt = 0;

	spin_lock_irqsave(&dev->devres_lock, flags);

	grp = find_group(dev, id);
	if (grp) {
		struct list_head *first = &grp->node[0].entry;
		struct list_head *end = &dev->devres_head;

		if (!list_empty(&grp->node[1].entry))
			end = grp->node[1].entry.next;

		cnt = release_nodes(dev, first, end, flags);
	} else {
		WARN_ON(1);
		spin_unlock_irqrestore(&dev->devres_lock, flags);
	}

	return cnt;
}
EXPORT_SYMBOL_GPL(devres_release_group);

/*
 * Custom devres actions allow inserting a simple function call
 * into the teadown sequence.
 */

struct action_devres {
	void *data;
	void (*action)(void *);
};

static int devm_action_match(struct device *dev, void *res, void *p)
{
	struct action_devres *devres = res;
	struct action_devres *target = p;

	return devres->action == target->action &&
	       devres->data == target->data;
}

static void devm_action_release(struct device *dev, void *res)
{
	struct action_devres *devres = res;

	devres->action(devres->data);
}

/**
 * devm_add_action() - add a custom action to list of managed resources
 * @dev: Device that owns the action
 * @action: Function that should be called
 * @data: Pointer to data passed to @action implementation
 *
 * This adds a custom action to the list of managed resources so that
 * it gets executed as part of standard resource unwinding.
 */
int devm_add_action(struct device *dev, void (*action)(void *), void *data)
{
	struct action_devres *devres;

	devres = devres_alloc(devm_action_release,
			      sizeof(struct action_devres), GFP_KERNEL);
	if (!devres)
		return -ENOMEM;

	devres->data = data;
	devres->action = action;

	devres_add(dev, devres);
	return 0;
}
EXPORT_SYMBOL_GPL(devm_add_action);

/**
 * devm_remove_action() - removes previously added custom action
 * @dev: Device that owns the action
 * @action: Function implementing the action
 * @data: Pointer to data passed to @action implementation
 *
 * Removes instance of @action previously added by devm_add_action().
 * Both action and data should match one of the existing entries.
 */
void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
{
	struct action_devres devres = {
		.data = data,
		.action = action,
	};

	WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
			       &devres));

}
EXPORT_SYMBOL_GPL(devm_remove_action);

/*
 * Managed kmalloc/kfree
 */
static void devm_kmalloc_release(struct device *dev, void *res)
{
	/* noop */
}

static int devm_kmalloc_match(struct device *dev, void *res, void *data)
{
	return res == data;
}

/**
 * devm_kmalloc - Resource-managed kmalloc
 * @dev: Device to allocate memory for
 * @size: Allocation size
 * @gfp: Allocation gfp flags
 *
 * Managed kmalloc.  Memory allocated with this function is
 * automatically freed on driver detach.  Like all other devres
 * resources, guaranteed alignment is unsigned long long.
 *
 * RETURNS:
 * Pointer to allocated memory on success, NULL on failure.
 */
void * devm_kmalloc(struct device *dev, size_t size, gfp_t gfp)
{
	struct devres *dr;

	/* use raw alloc_dr for kmalloc caller tracing */
	dr = alloc_dr(devm_kmalloc_release, size, gfp, dev_to_node(dev));
	if (unlikely(!dr))
		return NULL;

	/*
	 * This is named devm_kzalloc_release for historical reasons
	 * The initial implementation did not support kmalloc, only kzalloc
	 */
	set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
	devres_add(dev, dr->data);
	return dr->data;
}
EXPORT_SYMBOL_GPL(devm_kmalloc);

/**
 * devm_kstrdup - Allocate resource managed space and
 *                copy an existing string into that.
 * @dev: Device to allocate memory for
 * @s: the string to duplicate
 * @gfp: the GFP mask used in the devm_kmalloc() call when
 *       allocating memory
 * RETURNS:
 * Pointer to allocated string on success, NULL on failure.
 */
char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
{
	size_t size;
	char *buf;

	if (!s)
		return NULL;

	size = strlen(s) + 1;
	buf = devm_kmalloc(dev, size, gfp);
	if (buf)
		memcpy(buf, s, size);
	return buf;
}
EXPORT_SYMBOL_GPL(devm_kstrdup);

/**
 * devm_kstrdup_const - resource managed conditional string duplication
 * @dev: device for which to duplicate the string
 * @s: the string to duplicate
 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 *
 * Strings allocated by devm_kstrdup_const will be automatically freed when
 * the associated device is detached.
 *
 * RETURNS:
 * Source string if it is in .rodata section otherwise it falls back to
 * devm_kstrdup.
 */
const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
{
	if (is_kernel_rodata((unsigned long)s))
		return s;

	return devm_kstrdup(dev, s, gfp);
}
EXPORT_SYMBOL_GPL(devm_kstrdup_const);

/**
 * devm_kvasprintf - Allocate resource managed space and format a string
 *		     into that.
 * @dev: Device to allocate memory for
 * @gfp: the GFP mask used in the devm_kmalloc() call when
 *       allocating memory
 * @fmt: The printf()-style format string
 * @ap: Arguments for the format string
 * RETURNS:
 * Pointer to allocated string on success, NULL on failure.
 */
char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt,
		      va_list ap)
{
	unsigned int len;
	char *p;
	va_list aq;

	va_copy(aq, ap);
	len = vsnprintf(NULL, 0, fmt, aq);
	va_end(aq);

	p = devm_kmalloc(dev, len+1, gfp);
	if (!p)
		return NULL;

	vsnprintf(p, len+1, fmt, ap);

	return p;
}
EXPORT_SYMBOL(devm_kvasprintf);

/**
 * devm_kasprintf - Allocate resource managed space and format a string
 *		    into that.
 * @dev: Device to allocate memory for
 * @gfp: the GFP mask used in the devm_kmalloc() call when
 *       allocating memory
 * @fmt: The printf()-style format string
 * @...: Arguments for the format string
 * RETURNS:
 * Pointer to allocated string on success, NULL on failure.
 */
char *devm_kasprintf(struct device *dev, gfp_t gfp, const char *fmt, ...)
{
	va_list ap;
	char *p;

	va_start(ap, fmt);
	p = devm_kvasprintf(dev, gfp, fmt, ap);
	va_end(ap);

	return p;
}
EXPORT_SYMBOL_GPL(devm_kasprintf);

/**
 * devm_kfree - Resource-managed kfree
 * @dev: Device this memory belongs to
 * @p: Memory to free
 *
 * Free memory allocated with devm_kmalloc().
 */
void devm_kfree(struct device *dev, const void *p)
{
	int rc;

	/*
	 * Special case: pointer to a string in .rodata returned by
	 * devm_kstrdup_const().
	 */
	if (unlikely(is_kernel_rodata((unsigned long)p)))
		return;

	rc = devres_destroy(dev, devm_kmalloc_release,
			    devm_kmalloc_match, (void *)p);
	WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_kfree);

/**
 * devm_kmemdup - Resource-managed kmemdup
 * @dev: Device this memory belongs to
 * @src: Memory region to duplicate
 * @len: Memory region length
 * @gfp: GFP mask to use
 *
 * Duplicate region of a memory using resource managed kmalloc
 */
void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp)
{
	void *p;

	p = devm_kmalloc(dev, len, gfp);
	if (p)
		memcpy(p, src, len);

	return p;
}
EXPORT_SYMBOL_GPL(devm_kmemdup);

struct pages_devres {
	unsigned long addr;
	unsigned int order;
};

static int devm_pages_match(struct device *dev, void *res, void *p)
{
	struct pages_devres *devres = res;
	struct pages_devres *target = p;

	return devres->addr == target->addr;
}

static void devm_pages_release(struct device *dev, void *res)
{
	struct pages_devres *devres = res;

	free_pages(devres->addr, devres->order);
}

/**
 * devm_get_free_pages - Resource-managed __get_free_pages
 * @dev: Device to allocate memory for
 * @gfp_mask: Allocation gfp flags
 * @order: Allocation size is (1 << order) pages
 *
 * Managed get_free_pages.  Memory allocated with this function is
 * automatically freed on driver detach.
 *
 * RETURNS:
 * Address of allocated memory on success, 0 on failure.
 */

unsigned long devm_get_free_pages(struct device *dev,
				  gfp_t gfp_mask, unsigned int order)
{
	struct pages_devres *devres;
	unsigned long addr;

	addr = __get_free_pages(gfp_mask, order);

	if (unlikely(!addr))
		return 0;

	devres = devres_alloc(devm_pages_release,
			      sizeof(struct pages_devres), GFP_KERNEL);
	if (unlikely(!devres)) {
		free_pages(addr, order);
		return 0;
	}

	devres->addr = addr;
	devres->order = order;

	devres_add(dev, devres);
	return addr;
}
EXPORT_SYMBOL_GPL(devm_get_free_pages);

/**
 * devm_free_pages - Resource-managed free_pages
 * @dev: Device this memory belongs to
 * @addr: Memory to free
 *
 * Free memory allocated with devm_get_free_pages(). Unlike free_pages,
 * there is no need to supply the @order.
 */
void devm_free_pages(struct device *dev, unsigned long addr)
{
	struct pages_devres devres = { .addr = addr };

	WARN_ON(devres_release(dev, devm_pages_release, devm_pages_match,
			       &devres));
}
EXPORT_SYMBOL_GPL(devm_free_pages);

static void devm_percpu_release(struct device *dev, void *pdata)
{
	void __percpu *p;

	p = *(void __percpu **)pdata;
	free_percpu(p);
}

static int devm_percpu_match(struct device *dev, void *data, void *p)
{
	struct devres *devr = container_of(data, struct devres, data);

	return *(void **)devr->data == p;
}

/**
 * __devm_alloc_percpu - Resource-managed alloc_percpu
 * @dev: Device to allocate per-cpu memory for
 * @size: Size of per-cpu memory to allocate
 * @align: Alignment of per-cpu memory to allocate
 *
 * Managed alloc_percpu. Per-cpu memory allocated with this function is
 * automatically freed on driver detach.
 *
 * RETURNS:
 * Pointer to allocated memory on success, NULL on failure.
 */
void __percpu *__devm_alloc_percpu(struct device *dev, size_t size,
		size_t align)
{
	void *p;
	void __percpu *pcpu;

	pcpu = __alloc_percpu(size, align);
	if (!pcpu)
		return NULL;

	p = devres_alloc(devm_percpu_release, sizeof(void *), GFP_KERNEL);
	if (!p) {
		free_percpu(pcpu);
		return NULL;
	}

	*(void __percpu **)p = pcpu;

	devres_add(dev, p);

	return pcpu;
}
EXPORT_SYMBOL_GPL(__devm_alloc_percpu);

/**
 * devm_free_percpu - Resource-managed free_percpu
 * @dev: Device this memory belongs to
 * @pdata: Per-cpu memory to free
 *
 * Free memory allocated with devm_alloc_percpu().
 */
void devm_free_percpu(struct device *dev, void __percpu *pdata)
{
	WARN_ON(devres_destroy(dev, devm_percpu_release, devm_percpu_match,
			       (void *)pdata));
}
EXPORT_SYMBOL_GPL(devm_free_percpu);
OpenPOWER on IntegriCloud