Merge tag 'f2fs-for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk...
[sfrench/cifs-2.6.git] / drivers / md / bcache / util.c
1 /*
2  * random utiility code, for bcache but in theory not specific to bcache
3  *
4  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
5  * Copyright 2012 Google, Inc.
6  */
7
8 #include <linux/bio.h>
9 #include <linux/blkdev.h>
10 #include <linux/ctype.h>
11 #include <linux/debugfs.h>
12 #include <linux/module.h>
13 #include <linux/seq_file.h>
14 #include <linux/types.h>
15 #include <linux/sched/clock.h>
16
17 #include "util.h"
18
19 #define simple_strtoint(c, end, base)   simple_strtol(c, end, base)
20 #define simple_strtouint(c, end, base)  simple_strtoul(c, end, base)
21
22 #define STRTO_H(name, type)                                     \
23 int bch_ ## name ## _h(const char *cp, type *res)               \
24 {                                                               \
25         int u = 0;                                              \
26         char *e;                                                \
27         type i = simple_ ## name(cp, &e, 10);                   \
28                                                                 \
29         switch (tolower(*e)) {                                  \
30         default:                                                \
31                 return -EINVAL;                                 \
32         case 'y':                                               \
33         case 'z':                                               \
34                 u++;                                            \
35                 /* fall through */                              \
36         case 'e':                                               \
37                 u++;                                            \
38                 /* fall through */                              \
39         case 'p':                                               \
40                 u++;                                            \
41                 /* fall through */                              \
42         case 't':                                               \
43                 u++;                                            \
44                 /* fall through */                              \
45         case 'g':                                               \
46                 u++;                                            \
47                 /* fall through */                              \
48         case 'm':                                               \
49                 u++;                                            \
50                 /* fall through */                              \
51         case 'k':                                               \
52                 u++;                                            \
53                 if (e++ == cp)                                  \
54                         return -EINVAL;                         \
55                 /* fall through */                              \
56         case '\n':                                              \
57         case '\0':                                              \
58                 if (*e == '\n')                                 \
59                         e++;                                    \
60         }                                                       \
61                                                                 \
62         if (*e)                                                 \
63                 return -EINVAL;                                 \
64                                                                 \
65         while (u--) {                                           \
66                 if ((type) ~0 > 0 &&                            \
67                     (type) ~0 / 1024 <= i)                      \
68                         return -EINVAL;                         \
69                 if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) ||  \
70                     (i < 0 && -ANYSINT_MAX(type) / 1024 > i))   \
71                         return -EINVAL;                         \
72                 i *= 1024;                                      \
73         }                                                       \
74                                                                 \
75         *res = i;                                               \
76         return 0;                                               \
77 }                                                               \
78
79 STRTO_H(strtoint, int)
80 STRTO_H(strtouint, unsigned int)
81 STRTO_H(strtoll, long long)
82 STRTO_H(strtoull, unsigned long long)
83
84 /**
85  * bch_hprint - formats @v to human readable string for sysfs.
86  * @buf: the (at least 8 byte) buffer to format the result into.
87  * @v: signed 64 bit integer
88  *
89  * Returns the number of bytes used by format.
90  */
91 ssize_t bch_hprint(char *buf, int64_t v)
92 {
93         static const char units[] = "?kMGTPEZY";
94         int u = 0, t;
95
96         uint64_t q;
97
98         if (v < 0)
99                 q = -v;
100         else
101                 q = v;
102
103         /* For as long as the number is more than 3 digits, but at least
104          * once, shift right / divide by 1024.  Keep the remainder for
105          * a digit after the decimal point.
106          */
107         do {
108                 u++;
109
110                 t = q & ~(~0 << 10);
111                 q >>= 10;
112         } while (q >= 1000);
113
114         if (v < 0)
115                 /* '-', up to 3 digits, '.', 1 digit, 1 character, null;
116                  * yields 8 bytes.
117                  */
118                 return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);
119         else
120                 return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);
121 }
122
123 bool bch_is_zero(const char *p, size_t n)
124 {
125         size_t i;
126
127         for (i = 0; i < n; i++)
128                 if (p[i])
129                         return false;
130         return true;
131 }
132
133 int bch_parse_uuid(const char *s, char *uuid)
134 {
135         size_t i, j, x;
136         memset(uuid, 0, 16);
137
138         for (i = 0, j = 0;
139              i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
140              i++) {
141                 x = s[i] | 32;
142
143                 switch (x) {
144                 case '0'...'9':
145                         x -= '0';
146                         break;
147                 case 'a'...'f':
148                         x -= 'a' - 10;
149                         break;
150                 default:
151                         continue;
152                 }
153
154                 if (!(j & 1))
155                         x <<= 4;
156                 uuid[j++ >> 1] |= x;
157         }
158         return i;
159 }
160
161 void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
162 {
163         uint64_t now, duration, last;
164
165         spin_lock(&stats->lock);
166
167         now             = local_clock();
168         duration        = time_after64(now, start_time)
169                 ? now - start_time : 0;
170         last            = time_after64(now, stats->last)
171                 ? now - stats->last : 0;
172
173         stats->max_duration = max(stats->max_duration, duration);
174
175         if (stats->last) {
176                 ewma_add(stats->average_duration, duration, 8, 8);
177
178                 if (stats->average_frequency)
179                         ewma_add(stats->average_frequency, last, 8, 8);
180                 else
181                         stats->average_frequency  = last << 8;
182         } else {
183                 stats->average_duration  = duration << 8;
184         }
185
186         stats->last = now ?: 1;
187
188         spin_unlock(&stats->lock);
189 }
190
191 /**
192  * bch_next_delay() - update ratelimiting statistics and calculate next delay
193  * @d: the struct bch_ratelimit to update
194  * @done: the amount of work done, in arbitrary units
195  *
196  * Increment @d by the amount of work done, and return how long to delay in
197  * jiffies until the next time to do some work.
198  */
199 uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
200 {
201         uint64_t now = local_clock();
202
203         d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate));
204
205         /* Bound the time.  Don't let us fall further than 2 seconds behind
206          * (this prevents unnecessary backlog that would make it impossible
207          * to catch up).  If we're ahead of the desired writeback rate,
208          * don't let us sleep more than 2.5 seconds (so we can notice/respond
209          * if the control system tells us to speed up!).
210          */
211         if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))
212                 d->next = now + NSEC_PER_SEC * 5LLU / 2LLU;
213
214         if (time_after64(now - NSEC_PER_SEC * 2, d->next))
215                 d->next = now - NSEC_PER_SEC * 2;
216
217         return time_after64(d->next, now)
218                 ? div_u64(d->next - now, NSEC_PER_SEC / HZ)
219                 : 0;
220 }
221
222 /*
223  * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly,
224  * the preferred way is bio_add_page, but in this case, bch_bio_map()
225  * supposes that the bvec table is empty, so it is safe to access
226  * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is
227  * supported.
228  */
229 void bch_bio_map(struct bio *bio, void *base)
230 {
231         size_t size = bio->bi_iter.bi_size;
232         struct bio_vec *bv = bio->bi_io_vec;
233
234         BUG_ON(!bio->bi_iter.bi_size);
235         BUG_ON(bio->bi_vcnt);
236
237         bv->bv_offset = base ? offset_in_page(base) : 0;
238         goto start;
239
240         for (; size; bio->bi_vcnt++, bv++) {
241                 bv->bv_offset   = 0;
242 start:          bv->bv_len      = min_t(size_t, PAGE_SIZE - bv->bv_offset,
243                                         size);
244                 if (base) {
245                         bv->bv_page = is_vmalloc_addr(base)
246                                 ? vmalloc_to_page(base)
247                                 : virt_to_page(base);
248
249                         base += bv->bv_len;
250                 }
251
252                 size -= bv->bv_len;
253         }
254 }
255
256 /**
257  * bch_bio_alloc_pages - allocates a single page for each bvec in a bio
258  * @bio: bio to allocate pages for
259  * @gfp_mask: flags for allocation
260  *
261  * Allocates pages up to @bio->bi_vcnt.
262  *
263  * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
264  * freed.
265  */
266 int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
267 {
268         int i;
269         struct bio_vec *bv;
270
271         bio_for_each_segment_all(bv, bio, i) {
272                 bv->bv_page = alloc_page(gfp_mask);
273                 if (!bv->bv_page) {
274                         while (--bv >= bio->bi_io_vec)
275                                 __free_page(bv->bv_page);
276                         return -ENOMEM;
277                 }
278         }
279
280         return 0;
281 }