summaryrefslogtreecommitdiff
path: root/net/ethtool/bitset.c
blob: fce45dac42056b26a61ca71d527dfb70e3d16b33 (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
// SPDX-License-Identifier: GPL-2.0-only

#include <linux/ethtool_netlink.h>
#include <linux/bitmap.h>
#include "netlink.h"
#include "bitset.h"

/* Some bitmaps are internally represented as an array of unsigned long, some
 * as an array of u32 (some even as single u32 for now). To avoid the need of
 * wrappers on caller side, we provide two set of functions: those with "32"
 * suffix in their names expect u32 based bitmaps, those without it expect
 * unsigned long bitmaps.
 */

static u32 ethnl_lower_bits(unsigned int n)
{
	return ~(u32)0 >> (32 - n % 32);
}

static u32 ethnl_upper_bits(unsigned int n)
{
	return ~(u32)0 << (n % 32);
}

/**
 * ethnl_bitmap32_clear() - Clear u32 based bitmap
 * @dst:   bitmap to clear
 * @start: beginning of the interval
 * @end:   end of the interval
 * @mod:   set if bitmap was modified
 *
 * Clear @nbits bits of a bitmap with indices @start <= i < @end
 */
static void ethnl_bitmap32_clear(u32 *dst, unsigned int start, unsigned int end,
				 bool *mod)
{
	unsigned int start_word = start / 32;
	unsigned int end_word = end / 32;
	unsigned int i;
	u32 mask;

	if (end <= start)
		return;

	if (start % 32) {
		mask = ethnl_upper_bits(start);
		if (end_word == start_word) {
			mask &= ethnl_lower_bits(end);
			if (dst[start_word] & mask) {
				dst[start_word] &= ~mask;
				*mod = true;
			}
			return;
		}
		if (dst[start_word] & mask) {
			dst[start_word] &= ~mask;
			*mod = true;
		}
		start_word++;
	}

	for (i = start_word; i < end_word; i++) {
		if (dst[i]) {
			dst[i] = 0;
			*mod = true;
		}
	}
	if (end % 32) {
		mask = ethnl_lower_bits(end);
		if (dst[end_word] & mask) {
			dst[end_word] &= ~mask;
			*mod = true;
		}
	}
}

/**
 * ethnl_bitmap32_not_zero() - Check if any bit is set in an interval
 * @map:   bitmap to test
 * @start: beginning of the interval
 * @end:   end of the interval
 *
 * Return: true if there is non-zero bit with  index @start <= i < @end,
 *         false if the whole interval is zero
 */
static bool ethnl_bitmap32_not_zero(const u32 *map, unsigned int start,
				    unsigned int end)
{
	unsigned int start_word = start / 32;
	unsigned int end_word = end / 32;
	u32 mask;

	if (end <= start)
		return true;

	if (start % 32) {
		mask = ethnl_upper_bits(start);
		if (end_word == start_word) {
			mask &= ethnl_lower_bits(end);
			return map[start_word] & mask;
		}
		if (map[start_word] & mask)
			return true;
		start_word++;
	}

	if (!memchr_inv(map + start_word, '\0',
			(end_word - start_word) * sizeof(u32)))
		return true;
	if (end % 32 == 0)
		return true;
	return map[end_word] & ethnl_lower_bits(end);
}

/**
 * ethnl_bitmap32_update() - Modify u32 based bitmap according to value/mask
 *			     pair
 * @dst:   bitmap to update
 * @nbits: bit size of the bitmap
 * @value: values to set
 * @mask:  mask of bits to set
 * @mod:   set to true if bitmap is modified, preserve if not
 *
 * Set bits in @dst bitmap which are set in @mask to values from @value, leave
 * the rest untouched. If destination bitmap was modified, set @mod to true,
 * leave as it is if not.
 */
static void ethnl_bitmap32_update(u32 *dst, unsigned int nbits,
				  const u32 *value, const u32 *mask, bool *mod)
{
	while (nbits > 0) {
		u32 real_mask = mask ? *mask : ~(u32)0;
		u32 new_value;

		if (nbits < 32)
			real_mask &= ethnl_lower_bits(nbits);
		new_value = (*dst & ~real_mask) | (*value & real_mask);
		if (new_value != *dst) {
			*dst = new_value;
			*mod = true;
		}

		if (nbits <= 32)
			break;
		dst++;
		nbits -= 32;
		value++;
		if (mask)
			mask++;
	}
}

static bool ethnl_bitmap32_test_bit(const u32 *map, unsigned int index)
{
	return map[index / 32] & (1U << (index % 32));
}

/**
 * ethnl_bitset32_size() - Calculate size of bitset nested attribute
 * @val:     value bitmap (u32 based)
 * @mask:    mask bitmap (u32 based, optional)
 * @nbits:   bit length of the bitset
 * @names:   array of bit names (optional)
 * @compact: assume compact format for output
 *
 * Estimate length of netlink attribute composed by a later call to
 * ethnl_put_bitset32() call with the same arguments.
 *
 * Return: negative error code or attribute length estimate
 */
int ethnl_bitset32_size(const u32 *val, const u32 *mask, unsigned int nbits,
			ethnl_string_array_t names, bool compact)
{
	unsigned int len = 0;

	/* list flag */
	if (!mask)
		len += nla_total_size(sizeof(u32));
	/* size */
	len += nla_total_size(sizeof(u32));

	if (compact) {
		unsigned int nwords = DIV_ROUND_UP(nbits, 32);

		/* value, mask */
		len += (mask ? 2 : 1) * nla_total_size(nwords * sizeof(u32));
	} else {
		unsigned int bits_len = 0;
		unsigned int bit_len, i;

		for (i = 0; i < nbits; i++) {
			const char *name = names ? names[i] : NULL;

			if (!ethnl_bitmap32_test_bit(mask ?: val, i))
				continue;
			/* index */
			bit_len = nla_total_size(sizeof(u32));
			/* name */
			if (name)
				bit_len += ethnl_strz_size(name);
			/* value */
			if (mask && ethnl_bitmap32_test_bit(val, i))
				bit_len += nla_total_size(0);

			/* bit nest */
			bits_len += nla_total_size(bit_len);
		}
		/* bits nest */
		len += nla_total_size(bits_len);
	}

	/* outermost nest */
	return nla_total_size(len);
}

/**
 * ethnl_put_bitset32() - Put a bitset nest into a message
 * @skb:      skb with the message
 * @attrtype: attribute type for the bitset nest
 * @val:      value bitmap (u32 based)
 * @mask:     mask bitmap (u32 based, optional)
 * @nbits:    bit length of the bitset
 * @names:    array of bit names (optional)
 * @compact:  use compact format for the output
 *
 * Compose a nested attribute representing a bitset. If @mask is null, simple
 * bitmap (bit list) is created, if @mask is provided, represent a value/mask
 * pair. Bit names are only used in verbose mode and when provided by calller.
 *
 * Return: 0 on success, negative error value on error
 */
int ethnl_put_bitset32(struct sk_buff *skb, int attrtype, const u32 *val,
		       const u32 *mask, unsigned int nbits,
		       ethnl_string_array_t names, bool compact)
{
	struct nlattr *nest;
	struct nlattr *attr;

	nest = nla_nest_start(skb, attrtype);
	if (!nest)
		return -EMSGSIZE;

	if (!mask && nla_put_flag(skb, ETHTOOL_A_BITSET_NOMASK))
		goto nla_put_failure;
	if (nla_put_u32(skb, ETHTOOL_A_BITSET_SIZE, nbits))
		goto nla_put_failure;
	if (compact) {
		unsigned int nwords = DIV_ROUND_UP(nbits, 32);
		unsigned int nbytes = nwords * sizeof(u32);
		u32 *dst;

		attr = nla_reserve(skb, ETHTOOL_A_BITSET_VALUE, nbytes);
		if (!attr)
			goto nla_put_failure;
		dst = nla_data(attr);
		memcpy(dst, val, nbytes);
		if (nbits % 32)
			dst[nwords - 1] &= ethnl_lower_bits(nbits);

		if (mask) {
			attr = nla_reserve(skb, ETHTOOL_A_BITSET_MASK, nbytes);
			if (!attr)
				goto nla_put_failure;
			dst = nla_data(attr);
			memcpy(dst, mask, nbytes);
			if (nbits % 32)
				dst[nwords - 1] &= ethnl_lower_bits(nbits);
		}
	} else {
		struct nlattr *bits;
		unsigned int i;

		bits = nla_nest_start(skb, ETHTOOL_A_BITSET_BITS);
		if (!bits)
			goto nla_put_failure;
		for (i = 0; i < nbits; i++) {
			const char *name = names ? names[i] : NULL;

			if (!ethnl_bitmap32_test_bit(mask ?: val, i))
				continue;
			attr = nla_nest_start(skb, ETHTOOL_A_BITSET_BITS_BIT);
			if (!attr)
				goto nla_put_failure;
			if (nla_put_u32(skb, ETHTOOL_A_BITSET_BIT_INDEX, i))
				goto nla_put_failure;
			if (name &&
			    ethnl_put_strz(skb, ETHTOOL_A_BITSET_BIT_NAME, name))
				goto nla_put_failure;
			if (mask && ethnl_bitmap32_test_bit(val, i) &&
			    nla_put_flag(skb, ETHTOOL_A_BITSET_BIT_VALUE))
				goto nla_put_failure;
			nla_nest_end(skb, attr);
		}
		nla_nest_end(skb, bits);
	}

	nla_nest_end(skb, nest);
	return 0;

nla_put_failure:
	nla_nest_cancel(skb, nest);
	return -EMSGSIZE;
}

static const struct nla_policy bitset_policy[ETHTOOL_A_BITSET_MAX + 1] = {
	[ETHTOOL_A_BITSET_UNSPEC]	= { .type = NLA_REJECT },
	[ETHTOOL_A_BITSET_NOMASK]	= { .type = NLA_FLAG },
	[ETHTOOL_A_BITSET_SIZE]		= { .type = NLA_U32 },
	[ETHTOOL_A_BITSET_BITS]		= { .type = NLA_NESTED },
	[ETHTOOL_A_BITSET_VALUE]	= { .type = NLA_BINARY },
	[ETHTOOL_A_BITSET_MASK]		= { .type = NLA_BINARY },
};

static const struct nla_policy bit_policy[ETHTOOL_A_BITSET_BIT_MAX + 1] = {
	[ETHTOOL_A_BITSET_BIT_UNSPEC]	= { .type = NLA_REJECT },
	[ETHTOOL_A_BITSET_BIT_INDEX]	= { .type = NLA_U32 },
	[ETHTOOL_A_BITSET_BIT_NAME]	= { .type = NLA_NUL_STRING },
	[ETHTOOL_A_BITSET_BIT_VALUE]	= { .type = NLA_FLAG },
};

/**
 * ethnl_bitset_is_compact() - check if bitset attribute represents a compact
 *			       bitset
 * @bitset:  nested attribute representing a bitset
 * @compact: pointer for return value
 *
 * Return: 0 on success, negative error code on failure
 */
int ethnl_bitset_is_compact(const struct nlattr *bitset, bool *compact)
{
	struct nlattr *tb[ETHTOOL_A_BITSET_MAX + 1];
	int ret;

	ret = nla_parse_nested(tb, ETHTOOL_A_BITSET_MAX, bitset,
			       bitset_policy, NULL);
	if (ret < 0)
		return ret;

	if (tb[ETHTOOL_A_BITSET_BITS]) {
		if (tb[ETHTOOL_A_BITSET_VALUE] || tb[ETHTOOL_A_BITSET_MASK])
			return -EINVAL;
		*compact = false;
		return 0;
	}
	if (!tb[ETHTOOL_A_BITSET_SIZE] || !tb[ETHTOOL_A_BITSET_VALUE])
		return -EINVAL;

	*compact = true;
	return 0;
}

/**
 * ethnl_name_to_idx() - look up string index for a name
 * @names:   array of ETH_GSTRING_LEN sized strings
 * @n_names: number of strings in the array
 * @name:    name to look up
 *
 * Return: index of the string if found, -ENOENT if not found
 */
static int ethnl_name_to_idx(ethnl_string_array_t names, unsigned int n_names,
			     const char *name)
{
	unsigned int i;

	if (!names)
		return -ENOENT;

	for (i = 0; i < n_names; i++) {
		/* names[i] may not be null terminated */
		if (!strncmp(names[i], name, ETH_GSTRING_LEN) &&
		    strlen(name) <= ETH_GSTRING_LEN)
			return i;
	}

	return -ENOENT;
}

static int ethnl_parse_bit(unsigned int *index, bool *val, unsigned int nbits,
			   const struct nlattr *bit_attr, bool no_mask,
			   ethnl_string_array_t names,
			   struct netlink_ext_ack *extack)
{
	struct nlattr *tb[ETHTOOL_A_BITSET_BIT_MAX + 1];
	int ret, idx;

	ret = nla_parse_nested(tb, ETHTOOL_A_BITSET_BIT_MAX, bit_attr,
			       bit_policy, extack);
	if (ret < 0)
		return ret;

	if (tb[ETHTOOL_A_BITSET_BIT_INDEX]) {
		const char *name;

		idx = nla_get_u32(tb[ETHTOOL_A_BITSET_BIT_INDEX]);
		if (idx >= nbits) {
			NL_SET_ERR_MSG_ATTR(extack,
					    tb[ETHTOOL_A_BITSET_BIT_INDEX],
					    "bit index too high");
			return -EOPNOTSUPP;
		}
		name = names ? names[idx] : NULL;
		if (tb[ETHTOOL_A_BITSET_BIT_NAME] && name &&
		    strncmp(nla_data(tb[ETHTOOL_A_BITSET_BIT_NAME]), name,
			    nla_len(tb[ETHTOOL_A_BITSET_BIT_NAME]))) {
			NL_SET_ERR_MSG_ATTR(extack, bit_attr,
					    "bit index and name mismatch");
			return -EINVAL;
		}
	} else if (tb[ETHTOOL_A_BITSET_BIT_NAME]) {
		idx = ethnl_name_to_idx(names, nbits,
					nla_data(tb[ETHTOOL_A_BITSET_BIT_NAME]));
		if (idx < 0) {
			NL_SET_ERR_MSG_ATTR(extack,
					    tb[ETHTOOL_A_BITSET_BIT_NAME],
					    "bit name not found");
			return -EOPNOTSUPP;
		}
	} else {
		NL_SET_ERR_MSG_ATTR(extack, bit_attr,
				    "neither bit index nor name specified");
		return -EINVAL;
	}

	*index = idx;
	*val = no_mask || tb[ETHTOOL_A_BITSET_BIT_VALUE];
	return 0;
}

static int
ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits,
			      const struct nlattr *attr, struct nlattr **tb,
			      ethnl_string_array_t names,
			      struct netlink_ext_ack *extack, bool *mod)
{
	struct nlattr *bit_attr;
	bool no_mask;
	int rem;
	int ret;

	if (tb[ETHTOOL_A_BITSET_VALUE]) {
		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_VALUE],
				    "value only allowed in compact bitset");
		return -EINVAL;
	}
	if (tb[ETHTOOL_A_BITSET_MASK]) {
		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
				    "mask only allowed in compact bitset");
		return -EINVAL;
	}
	no_mask = tb[ETHTOOL_A_BITSET_NOMASK];

	nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) {
		bool old_val, new_val;
		unsigned int idx;

		if (nla_type(bit_attr) != ETHTOOL_A_BITSET_BITS_BIT) {
			NL_SET_ERR_MSG_ATTR(extack, bit_attr,
					    "only ETHTOOL_A_BITSET_BITS_BIT allowed in ETHTOOL_A_BITSET_BITS");
			return -EINVAL;
		}
		ret = ethnl_parse_bit(&idx, &new_val, nbits, bit_attr, no_mask,
				      names, extack);
		if (ret < 0)
			return ret;
		old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32));
		if (new_val != old_val) {
			if (new_val)
				bitmap[idx / 32] |= ((u32)1 << (idx % 32));
			else
				bitmap[idx / 32] &= ~((u32)1 << (idx % 32));
			*mod = true;
		}
	}

	return 0;
}

static int ethnl_compact_sanity_checks(unsigned int nbits,
				       const struct nlattr *nest,
				       struct nlattr **tb,
				       struct netlink_ext_ack *extack)
{
	bool no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
	unsigned int attr_nbits, attr_nwords;
	const struct nlattr *test_attr;

	if (no_mask && tb[ETHTOOL_A_BITSET_MASK]) {
		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
				    "mask not allowed in list bitset");
		return -EINVAL;
	}
	if (!tb[ETHTOOL_A_BITSET_SIZE]) {
		NL_SET_ERR_MSG_ATTR(extack, nest,
				    "missing size in compact bitset");
		return -EINVAL;
	}
	if (!tb[ETHTOOL_A_BITSET_VALUE]) {
		NL_SET_ERR_MSG_ATTR(extack, nest,
				    "missing value in compact bitset");
		return -EINVAL;
	}
	if (!no_mask && !tb[ETHTOOL_A_BITSET_MASK]) {
		NL_SET_ERR_MSG_ATTR(extack, nest,
				    "missing mask in compact nonlist bitset");
		return -EINVAL;
	}

	attr_nbits = nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]);
	attr_nwords = DIV_ROUND_UP(attr_nbits, 32);
	if (nla_len(tb[ETHTOOL_A_BITSET_VALUE]) != attr_nwords * sizeof(u32)) {
		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_VALUE],
				    "bitset value length does not match size");
		return -EINVAL;
	}
	if (tb[ETHTOOL_A_BITSET_MASK] &&
	    nla_len(tb[ETHTOOL_A_BITSET_MASK]) != attr_nwords * sizeof(u32)) {
		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
				    "bitset mask length does not match size");
		return -EINVAL;
	}
	if (attr_nbits <= nbits)
		return 0;

	test_attr = no_mask ? tb[ETHTOOL_A_BITSET_VALUE] :
			      tb[ETHTOOL_A_BITSET_MASK];
	if (ethnl_bitmap32_not_zero(nla_data(test_attr), nbits, attr_nbits)) {
		NL_SET_ERR_MSG_ATTR(extack, test_attr,
				    "cannot modify bits past kernel bitset size");
		return -EINVAL;
	}
	return 0;
}

/**
 * ethnl_update_bitset32() - Apply a bitset nest to a u32 based bitmap
 * @bitmap:  bitmap to update
 * @nbits:   size of the updated bitmap in bits
 * @attr:    nest attribute to parse and apply
 * @names:   array of bit names; may be null for compact format
 * @extack:  extack for error reporting
 * @mod:     set this to true if bitmap is modified, leave as it is if not
 *
 * Apply bitset netsted attribute to a bitmap. If the attribute represents
 * a bit list, @bitmap is set to its contents; otherwise, bits in mask are
 * set to values from value. Bitmaps in the attribute may be longer than
 * @nbits but the message must not request modifying any bits past @nbits.
 *
 * Return: negative error code on failure, 0 on success
 */
int ethnl_update_bitset32(u32 *bitmap, unsigned int nbits,
			  const struct nlattr *attr, ethnl_string_array_t names,
			  struct netlink_ext_ack *extack, bool *mod)
{
	struct nlattr *tb[ETHTOOL_A_BITSET_MAX + 1];
	unsigned int change_bits;
	bool no_mask;
	int ret;

	if (!attr)
		return 0;
	ret = nla_parse_nested(tb, ETHTOOL_A_BITSET_MAX, attr, bitset_policy,
			       extack);
	if (ret < 0)
		return ret;

	if (tb[ETHTOOL_A_BITSET_BITS])
		return ethnl_update_bitset32_verbose(bitmap, nbits, attr, tb,
						     names, extack, mod);
	ret = ethnl_compact_sanity_checks(nbits, attr, tb, extack);
	if (ret < 0)
		return ret;

	no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
	change_bits = min_t(unsigned int,
			    nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]), nbits);
	ethnl_bitmap32_update(bitmap, change_bits,
			      nla_data(tb[ETHTOOL_A_BITSET_VALUE]),
			      no_mask ? NULL :
					nla_data(tb[ETHTOOL_A_BITSET_MASK]),
			      mod);
	if (no_mask && change_bits < nbits)
		ethnl_bitmap32_clear(bitmap, change_bits, nbits, mod);

	return 0;
}

#if BITS_PER_LONG == 64 && defined(__BIG_ENDIAN)

/* 64-bit big endian architectures are the only case when u32 based bitmaps
 * and unsigned long based bitmaps have different memory layout so that we
 * cannot simply cast the latter to the former and need actual wrappers
 * converting the latter to the former.
 *
 * To reduce the number of slab allocations, the wrappers use fixed size local
 * variables for bitmaps up to ETHNL_SMALL_BITMAP_BITS bits which is the
 * majority of bitmaps used by ethtool.
 */
#define ETHNL_SMALL_BITMAP_BITS 128
#define ETHNL_SMALL_BITMAP_WORDS DIV_ROUND_UP(ETHNL_SMALL_BITMAP_BITS, 32)

int ethnl_bitset_size(const unsigned long *val, const unsigned long *mask,
		      unsigned int nbits, ethnl_string_array_t names,
		      bool compact)
{
	u32 small_mask32[ETHNL_SMALL_BITMAP_WORDS];
	u32 small_val32[ETHNL_SMALL_BITMAP_WORDS];
	u32 *mask32;
	u32 *val32;
	int ret;

	if (nbits > ETHNL_SMALL_BITMAP_BITS) {
		unsigned int nwords = DIV_ROUND_UP(nbits, 32);

		val32 = kmalloc_array(2 * nwords, sizeof(u32), GFP_KERNEL);
		if (!val32)
			return -ENOMEM;
		mask32 = val32 + nwords;
	} else {
		val32 = small_val32;
		mask32 = small_mask32;
	}

	bitmap_to_arr32(val32, val, nbits);
	if (mask)
		bitmap_to_arr32(mask32, mask, nbits);
	else
		mask32 = NULL;
	ret = ethnl_bitset32_size(val32, mask32, nbits, names, compact);

	if (nbits > ETHNL_SMALL_BITMAP_BITS)
		kfree(val32);

	return ret;
}

int ethnl_put_bitset(struct sk_buff *skb, int attrtype,
		     const unsigned long *val, const unsigned long *mask,
		     unsigned int nbits, ethnl_string_array_t names,
		     bool compact)
{
	u32 small_mask32[ETHNL_SMALL_BITMAP_WORDS];
	u32 small_val32[ETHNL_SMALL_BITMAP_WORDS];
	u32 *mask32;
	u32 *val32;
	int ret;

	if (nbits > ETHNL_SMALL_BITMAP_BITS) {
		unsigned int nwords = DIV_ROUND_UP(nbits, 32);

		val32 = kmalloc_array(2 * nwords, sizeof(u32), GFP_KERNEL);
		if (!val32)
			return -ENOMEM;
		mask32 = val32 + nwords;
	} else {
		val32 = small_val32;
		mask32 = small_mask32;
	}

	bitmap_to_arr32(val32, val, nbits);
	if (mask)
		bitmap_to_arr32(mask32, mask, nbits);
	else
		mask32 = NULL;
	ret = ethnl_put_bitset32(skb, attrtype, val32, mask32, nbits, names,
				 compact);

	if (nbits > ETHNL_SMALL_BITMAP_BITS)
		kfree(val32);

	return ret;
}

int ethnl_update_bitset(unsigned long *bitmap, unsigned int nbits,
			const struct nlattr *attr, ethnl_string_array_t names,
			struct netlink_ext_ack *extack, bool *mod)
{
	u32 small_bitmap32[ETHNL_SMALL_BITMAP_WORDS];
	u32 *bitmap32 = small_bitmap32;
	bool u32_mod = false;
	int ret;

	if (nbits > ETHNL_SMALL_BITMAP_BITS) {
		unsigned int dst_words = DIV_ROUND_UP(nbits, 32);

		bitmap32 = kmalloc_array(dst_words, sizeof(u32), GFP_KERNEL);
		if (!bitmap32)
			return -ENOMEM;
	}

	bitmap_to_arr32(bitmap32, bitmap, nbits);
	ret = ethnl_update_bitset32(bitmap32, nbits, attr, names, extack,
				    &u32_mod);
	if (u32_mod) {
		bitmap_from_arr32(bitmap, bitmap32, nbits);
		*mod = true;
	}

	if (nbits > ETHNL_SMALL_BITMAP_BITS)
		kfree(bitmap32);

	return ret;
}

#else

/* On little endian 64-bit and all 32-bit architectures, an unsigned long
 * based bitmap can be interpreted as u32 based one using a simple cast.
 */

int ethnl_bitset_size(const unsigned long *val, const unsigned long *mask,
		      unsigned int nbits, ethnl_string_array_t names,
		      bool compact)
{
	return ethnl_bitset32_size((const u32 *)val, (const u32 *)mask, nbits,
				   names, compact);
}

int ethnl_put_bitset(struct sk_buff *skb, int attrtype,
		     const unsigned long *val, const unsigned long *mask,
		     unsigned int nbits, ethnl_string_array_t names,
		     bool compact)
{
	return ethnl_put_bitset32(skb, attrtype, (const u32 *)val,
				  (const u32 *)mask, nbits, names, compact);
}

int ethnl_update_bitset(unsigned long *bitmap, unsigned int nbits,
			const struct nlattr *attr, ethnl_string_array_t names,
			struct netlink_ext_ack *extack, bool *mod)
{
	return ethnl_update_bitset32((u32 *)bitmap, nbits, attr, names, extack,
				     mod);
}

#endif /* BITS_PER_LONG == 64 && defined(__BIG_ENDIAN) */