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
blkg_rwstat_init(struct blkg_rwstat * rwstat,gfp_t gfp)8 int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
9 {
10 int i, ret;
11
12 for (i = 0; i < BLKG_RWSTAT_NR; i++) {
13 ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
14 if (ret) {
15 while (--i >= 0)
16 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
17 return ret;
18 }
19 atomic64_set(&rwstat->aux_cnt[i], 0);
20 }
21 return 0;
22 }
23 EXPORT_SYMBOL_GPL(blkg_rwstat_init);
24
blkg_rwstat_exit(struct blkg_rwstat * rwstat)25 void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
26 {
27 int i;
28
29 for (i = 0; i < BLKG_RWSTAT_NR; i++)
30 percpu_counter_destroy(&rwstat->cpu_cnt[i]);
31 }
32 EXPORT_SYMBOL_GPL(blkg_rwstat_exit);
33
34 /**
35 * __blkg_prfill_rwstat - prfill helper for a blkg_rwstat
36 * @sf: seq_file to print to
37 * @pd: policy private data of interest
38 * @rwstat: rwstat to print
39 *
40 * Print @rwstat to @sf for the device assocaited with @pd.
41 */
__blkg_prfill_rwstat(struct seq_file * sf,struct blkg_policy_data * pd,const struct blkg_rwstat_sample * rwstat)42 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
43 const struct blkg_rwstat_sample *rwstat)
44 {
45 static const char *rwstr[] = {
46 [BLKG_RWSTAT_READ] = "Read",
47 [BLKG_RWSTAT_WRITE] = "Write",
48 [BLKG_RWSTAT_SYNC] = "Sync",
49 [BLKG_RWSTAT_ASYNC] = "Async",
50 [BLKG_RWSTAT_DISCARD] = "Discard",
51 };
52 const char *dname = blkg_dev_name(pd->blkg);
53 u64 v;
54 int i;
55
56 if (!dname)
57 return 0;
58
59 for (i = 0; i < BLKG_RWSTAT_NR; i++)
60 seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],
61 rwstat->cnt[i]);
62
63 v = rwstat->cnt[BLKG_RWSTAT_READ] +
64 rwstat->cnt[BLKG_RWSTAT_WRITE] +
65 rwstat->cnt[BLKG_RWSTAT_DISCARD];
66 seq_printf(sf, "%s Total %llu\n", dname, v);
67 return v;
68 }
69 EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
70
71 /**
72 * blkg_prfill_rwstat - prfill callback for blkg_rwstat
73 * @sf: seq_file to print to
74 * @pd: policy private data of interest
75 * @off: offset to the blkg_rwstat in @pd
76 *
77 * prfill callback for printing a blkg_rwstat.
78 */
blkg_prfill_rwstat(struct seq_file * sf,struct blkg_policy_data * pd,int off)79 u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
80 int off)
81 {
82 struct blkg_rwstat_sample rwstat = { };
83
84 blkg_rwstat_read((void *)pd + off, &rwstat);
85 return __blkg_prfill_rwstat(sf, pd, &rwstat);
86 }
87 EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
88
89 /**
90 * blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
91 * @blkg: blkg of interest
92 * @pol: blkcg_policy which contains the blkg_rwstat
93 * @off: offset to the blkg_rwstat in blkg_policy_data or @blkg
94 * @sum: blkg_rwstat_sample structure containing the results
95 *
96 * Collect the blkg_rwstat specified by @blkg, @pol and @off and all its
97 * online descendants and their aux counts. The caller must be holding the
98 * queue lock for online tests.
99 *
100 * If @pol is NULL, blkg_rwstat is at @off bytes into @blkg; otherwise, it
101 * is at @off bytes into @blkg's blkg_policy_data of the policy.
102 */
blkg_rwstat_recursive_sum(struct blkcg_gq * blkg,struct blkcg_policy * pol,int off,struct blkg_rwstat_sample * sum)103 void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
104 int off, struct blkg_rwstat_sample *sum)
105 {
106 struct blkcg_gq *pos_blkg;
107 struct cgroup_subsys_state *pos_css;
108 unsigned int i;
109
110 lockdep_assert_held(&blkg->q->queue_lock);
111
112 rcu_read_lock();
113 blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
114 struct blkg_rwstat *rwstat;
115
116 if (!pos_blkg->online)
117 continue;
118
119 if (pol)
120 rwstat = (void *)blkg_to_pd(pos_blkg, pol) + off;
121 else
122 rwstat = (void *)pos_blkg + off;
123
124 for (i = 0; i < BLKG_RWSTAT_NR; i++)
125 sum->cnt[i] = blkg_rwstat_read_counter(rwstat, i);
126 }
127 rcu_read_unlock();
128 }
129 EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);
130
