summaryrefslogtreecommitdiffstats
path: root/drivers/md/bcache/util.c
blob: 62fb917f7a4f08231656b1abb6fa18594012f7ff (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
// SPDX-License-Identifier: GPL-2.0
/*
 * random utiility code, for bcache but in theory not specific to bcache
 *
 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
 * Copyright 2012 Google, Inc.
 */

#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/types.h>
#include <linux/sched/clock.h>

#include "util.h"

#define simple_strtoint(c, end, base)	simple_strtol(c, end, base)
#define simple_strtouint(c, end, base)	simple_strtoul(c, end, base)

#define STRTO_H(name, type)					\
int bch_ ## name ## _h(const char *cp, type *res)		\
{								\
	int u = 0;						\
	char *e;						\
	type i = simple_ ## name(cp, &e, 10);			\
								\
	switch (tolower(*e)) {					\
	default:						\
		return -EINVAL;					\
	case 'y':						\
	case 'z':						\
		u++;						\
		/* fall through */				\
	case 'e':						\
		u++;						\
		/* fall through */				\
	case 'p':						\
		u++;						\
		/* fall through */				\
	case 't':						\
		u++;						\
		/* fall through */				\
	case 'g':						\
		u++;						\
		/* fall through */				\
	case 'm':						\
		u++;						\
		/* fall through */				\
	case 'k':						\
		u++;						\
		if (e++ == cp)					\
			return -EINVAL;				\
		/* fall through */				\
	case '\n':						\
	case '\0':						\
		if (*e == '\n')					\
			e++;					\
	}							\
								\
	if (*e)							\
		return -EINVAL;					\
								\
	while (u--) {						\
		if ((type) ~0 > 0 &&				\
		    (type) ~0 / 1024 <= i)			\
			return -EINVAL;				\
		if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) ||	\
		    (i < 0 && -ANYSINT_MAX(type) / 1024 > i))	\
			return -EINVAL;				\
		i *= 1024;					\
	}							\
								\
	*res = i;						\
	return 0;						\
}								\

STRTO_H(strtoint, int)
STRTO_H(strtouint, unsigned int)
STRTO_H(strtoll, long long)
STRTO_H(strtoull, unsigned long long)

/**
 * bch_hprint - formats @v to human readable string for sysfs.
 * @buf: the (at least 8 byte) buffer to format the result into.
 * @v: signed 64 bit integer
 *
 * Returns the number of bytes used by format.
 */
ssize_t bch_hprint(char *buf, int64_t v)
{
	static const char units[] = "?kMGTPEZY";
	int u = 0, t;

	uint64_t q;

	if (v < 0)
		q = -v;
	else
		q = v;

	/* For as long as the number is more than 3 digits, but at least
	 * once, shift right / divide by 1024.  Keep the remainder for
	 * a digit after the decimal point.
	 */
	do {
		u++;

		t = q & ~(~0 << 10);
		q >>= 10;
	} while (q >= 1000);

	if (v < 0)
		/* '-', up to 3 digits, '.', 1 digit, 1 character, null;
		 * yields 8 bytes.
		 */
		return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);
	else
		return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);
}

bool bch_is_zero(const char *p, size_t n)
{
	size_t i;

	for (i = 0; i < n; i++)
		if (p[i])
			return false;
	return true;
}

int bch_parse_uuid(const char *s, char *uuid)
{
	size_t i, j, x;

	memset(uuid, 0, 16);

	for (i = 0, j = 0;
	     i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
	     i++) {
		x = s[i] | 32;

		switch (x) {
		case '0'...'9':
			x -= '0';
			break;
		case 'a'...'f':
			x -= 'a' - 10;
			break;
		default:
			continue;
		}

		if (!(j & 1))
			x <<= 4;
		uuid[j++ >> 1] |= x;
	}
	return i;
}

void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
{
	uint64_t now, duration, last;

	spin_lock(&stats->lock);

	now		= local_clock();
	duration	= time_after64(now, start_time)
		? now - start_time : 0;
	last		= time_after64(now, stats->last)
		? now - stats->last : 0;

	stats->max_duration = max(stats->max_duration, duration);

	if (stats->last) {
		ewma_add(stats->average_duration, duration, 8, 8);

		if (stats->average_frequency)
			ewma_add(stats->average_frequency, last, 8, 8);
		else
			stats->average_frequency  = last << 8;
	} else {
		stats->average_duration  = duration << 8;
	}

	stats->last = now ?: 1;

	spin_unlock(&stats->lock);
}

/**
 * bch_next_delay() - update ratelimiting statistics and calculate next delay
 * @d: the struct bch_ratelimit to update
 * @done: the amount of work done, in arbitrary units
 *
 * Increment @d by the amount of work done, and return how long to delay in
 * jiffies until the next time to do some work.
 */
uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
{
	uint64_t now = local_clock();

	d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate));

	/* Bound the time.  Don't let us fall further than 2 seconds behind
	 * (this prevents unnecessary backlog that would make it impossible
	 * to catch up).  If we're ahead of the desired writeback rate,
	 * don't let us sleep more than 2.5 seconds (so we can notice/respond
	 * if the control system tells us to speed up!).
	 */
	if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))
		d->next = now + NSEC_PER_SEC * 5LLU / 2LLU;

	if (time_after64(now - NSEC_PER_SEC * 2, d->next))
		d->next = now - NSEC_PER_SEC * 2;

	return time_after64(d->next, now)
		? div_u64(d->next - now, NSEC_PER_SEC / HZ)
		: 0;
}

/*
 * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly,
 * the preferred way is bio_add_page, but in this case, bch_bio_map()
 * supposes that the bvec table is empty, so it is safe to access
 * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is
 * supported.
 */
void bch_bio_map(struct bio *bio, void *base)
{
	size_t size = bio->bi_iter.bi_size;
	struct bio_vec *bv = bio->bi_io_vec;

	BUG_ON(!bio->bi_iter.bi_size);
	BUG_ON(bio->bi_vcnt);

	bv->bv_offset = base ? offset_in_page(base) : 0;
	goto start;

	for (; size; bio->bi_vcnt++, bv++) {
		bv->bv_offset	= 0;
start:		bv->bv_len	= min_t(size_t, PAGE_SIZE - bv->bv_offset,
					size);
		if (base) {
			bv->bv_page = is_vmalloc_addr(base)
				? vmalloc_to_page(base)
				: virt_to_page(base);

			base += bv->bv_len;
		}

		size -= bv->bv_len;
	}
}

/**
 * bch_bio_alloc_pages - allocates a single page for each bvec in a bio
 * @bio: bio to allocate pages for
 * @gfp_mask: flags for allocation
 *
 * Allocates pages up to @bio->bi_vcnt.
 *
 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
 * freed.
 */
int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
{
	int i;
	struct bio_vec *bv;

	/*
	 * This is called on freshly new bio, so it is safe to access the
	 * bvec table directly.
	 */
	for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) {
		bv->bv_page = alloc_page(gfp_mask);
		if (!bv->bv_page) {
			while (--bv >= bio->bi_io_vec)
				__free_page(bv->bv_page);
			return -ENOMEM;
		}
	}

	return 0;
}