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. 92 * 93 * If @pol is NULL, blkg_rwstat is at @off bytes into @blkg; otherwise, it 94 * is at @off bytes into @blkg's blkg_policy_data of the policy. 95 */ 96 void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, 97 int off, struct blkg_rwstat_sample *sum) 98 { 99 struct blkcg_gq *pos_blkg; 100 struct cgroup_subsys_state *pos_css; 101 unsigned int i; 102 103 WARN_ON_ONCE(!rcu_read_lock_held()); 104 105 memset(sum, 0, sizeof(*sum)); 106 blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) { 107 struct blkg_rwstat *rwstat; 108 109 if (!data_race(pos_blkg->online)) 110 continue; 111 112 if (pol) { 113 struct blkg_policy_data *pd = blkg_to_pd(pos_blkg, pol); 114 115 if (!pd) 116 continue; 117 rwstat = (void *)pd + off; 118 } else { 119 rwstat = (void *)pos_blkg + off; 120 } 121 122 for (i = 0; i < BLKG_RWSTAT_NR; i++) 123 sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i); 124 } 125 } 126 EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum); 127