1 /* SPDX-License-Identifier: GPL-2.0
2 *
3 * Legacy blkg rwstat helpers enabled by CONFIG_BLK_CGROUP_RWSTAT.
4 * Do not use in new code.
5 */
6 #include "blk-cgroup-rwstat.h"
7
8 int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
9 {
10 int i, ret;
11
12 ret = percpu_counter_init_many(rwstat->cpu_cnt, 0, gfp, BLKG_RWSTAT_NR);
13 if (ret)
14 return ret;
15
16 for (i = 0; i < BLKG_RWSTAT_NR; i++)
17 atomic64_set(&rwstat->aux_cnt[i], 0);
18 return 0;
19 }
20 EXPORT_SYMBOL_GPL(blkg_rwstat_init);
21
22 void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
23 {
24 percpu_counter_destroy_many(rwstat->cpu_cnt, BLKG_RWSTAT_NR);
25 }
26 EXPORT_SYMBOL_GPL(blkg_rwstat_exit);
27
28 /**
29 * __blkg_prfill_rwstat - prfill helper for a blkg_rwstat
30 * @sf: seq_file to print to
31 * @pd: policy private data of interest
32 * @rwstat: rwstat to print
33 *
34 * Print @rwstat to @sf for the device assocaited with @pd.
35 */
36 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
37 const struct blkg_rwstat_sample *rwstat)
38 {
39 static const char *rwstr[] = {
40 [BLKG_RWSTAT_READ] = "Read",
41 [BLKG_RWSTAT_WRITE] = "Write",
42 [BLKG_RWSTAT_SYNC] = "Sync",
43 [BLKG_RWSTAT_ASYNC] = "Async",
44 [BLKG_RWSTAT_DISCARD] = "Discard",
45 };
46 const char *dname = blkg_dev_name(pd->blkg);
47 u64 v;
48 int i;
49
50 if (!dname)
51 return 0;
52
53 for (i = 0; i < BLKG_RWSTAT_NR; i++)
54 seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],
55 rwstat->cnt[i]);
56
57 v = rwstat->cnt[BLKG_RWSTAT_READ] +
58 rwstat->cnt[BLKG_RWSTAT_WRITE] +
59 rwstat->cnt[BLKG_RWSTAT_DISCARD];
60 seq_printf(sf, "%s Total %llu\n", dname, v);
61 return v;
62 }
63 EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
64
65 /**
66 * blkg_prfill_rwstat - prfill callback for blkg_rwstat
67 * @sf: seq_file to print to
68 * @pd: policy private data of interest
69 * @off: offset to the blkg_rwstat in @pd
70 *
71 * prfill callback for printing a blkg_rwstat.
72 */
73 u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
74 int off)
75 {
76 struct blkg_rwstat_sample rwstat = { };
77
78 blkg_rwstat_read((void *)pd + off, &rwstat);
79 return __blkg_prfill_rwstat(sf, pd, &rwstat);
80 }
81 EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
82
83 /**
84 * blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
85 * @blkg: blkg of interest
86 * @pol: blkcg_policy which contains the blkg_rwstat
87 * @off: offset to the blkg_rwstat in blkg_policy_data or @blkg
88 * @sum: blkg_rwstat_sample structure containing the results
89 *
90 * Collect the blkg_rwstat specified by @blkg, @pol and @off and all its
91 * online descendants and their aux counts. The caller must be holding the
92 * queue lock for online tests.
93 *
94 * If @pol is NULL, blkg_rwstat is at @off bytes into @blkg; otherwise, it
95 * is at @off bytes into @blkg's blkg_policy_data of the policy.
96 */
97 void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
98 int off, struct blkg_rwstat_sample *sum)
99 {
100 struct blkcg_gq *pos_blkg;
101 struct cgroup_subsys_state *pos_css;
102 unsigned int i;
103
104 lockdep_assert_held(&blkg->q->queue_lock);
105
106 memset(sum, 0, sizeof(*sum));
107 rcu_read_lock();
108 blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
109 struct blkg_rwstat *rwstat;
110
111 if (!pos_blkg->online)
112 continue;
113
114 if (pol)
115 rwstat = (void *)blkg_to_pd(pos_blkg, pol) + off;
116 else
117 rwstat = (void *)pos_blkg + off;
118
119 for (i = 0; i < BLKG_RWSTAT_NR; i++)
120 sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i);
121 }
122 rcu_read_unlock();
123 }
124 EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);
125
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