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 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 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 */ 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 */ 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 */ 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 memset(sum, 0, sizeof(*sum)); 113 rcu_read_lock(); 114 blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) { 115 struct blkg_rwstat *rwstat; 116 117 if (!pos_blkg->online) 118 continue; 119 120 if (pol) 121 rwstat = (void *)blkg_to_pd(pos_blkg, pol) + off; 122 else 123 rwstat = (void *)pos_blkg + off; 124 125 for (i = 0; i < BLKG_RWSTAT_NR; i++) 126 sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i); 127 } 128 rcu_read_unlock(); 129 } 130 EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum); 131