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- /* SPDX-License-Identifier: GPL-2.0
- *
- * Legacy blkg rwstat helpers enabled by CONFIG_BLK_CGROUP_RWSTAT.
- * Do not use in new code.
- */
- #include "blk-cgroup-rwstat.h"
- int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
- {
- int i, ret;
- for (i = 0; i < BLKG_RWSTAT_NR; i++) {
- ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
- if (ret) {
- while (--i >= 0)
- percpu_counter_destroy(&rwstat->cpu_cnt[i]);
- return ret;
- }
- atomic64_set(&rwstat->aux_cnt[i], 0);
- }
- return 0;
- }
- EXPORT_SYMBOL_GPL(blkg_rwstat_init);
- void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
- {
- int i;
- for (i = 0; i < BLKG_RWSTAT_NR; i++)
- percpu_counter_destroy(&rwstat->cpu_cnt[i]);
- }
- EXPORT_SYMBOL_GPL(blkg_rwstat_exit);
- /**
- * __blkg_prfill_rwstat - prfill helper for a blkg_rwstat
- * @sf: seq_file to print to
- * @pd: policy private data of interest
- * @rwstat: rwstat to print
- *
- * Print @rwstat to @sf for the device assocaited with @pd.
- */
- u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
- const struct blkg_rwstat_sample *rwstat)
- {
- static const char *rwstr[] = {
- [BLKG_RWSTAT_READ] = "Read",
- [BLKG_RWSTAT_WRITE] = "Write",
- [BLKG_RWSTAT_SYNC] = "Sync",
- [BLKG_RWSTAT_ASYNC] = "Async",
- [BLKG_RWSTAT_DISCARD] = "Discard",
- };
- const char *dname = blkg_dev_name(pd->blkg);
- u64 v;
- int i;
- if (!dname)
- return 0;
- for (i = 0; i < BLKG_RWSTAT_NR; i++)
- seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],
- rwstat->cnt[i]);
- v = rwstat->cnt[BLKG_RWSTAT_READ] +
- rwstat->cnt[BLKG_RWSTAT_WRITE] +
- rwstat->cnt[BLKG_RWSTAT_DISCARD];
- seq_printf(sf, "%s Total %llu\n", dname, v);
- return v;
- }
- EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
- /**
- * blkg_prfill_rwstat - prfill callback for blkg_rwstat
- * @sf: seq_file to print to
- * @pd: policy private data of interest
- * @off: offset to the blkg_rwstat in @pd
- *
- * prfill callback for printing a blkg_rwstat.
- */
- u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
- int off)
- {
- struct blkg_rwstat_sample rwstat = { };
- blkg_rwstat_read((void *)pd + off, &rwstat);
- return __blkg_prfill_rwstat(sf, pd, &rwstat);
- }
- EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
- /**
- * blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
- * @blkg: blkg of interest
- * @pol: blkcg_policy which contains the blkg_rwstat
- * @off: offset to the blkg_rwstat in blkg_policy_data or @blkg
- * @sum: blkg_rwstat_sample structure containing the results
- *
- * Collect the blkg_rwstat specified by @blkg, @pol and @off and all its
- * online descendants and their aux counts. The caller must be holding the
- * queue lock for online tests.
- *
- * If @pol is NULL, blkg_rwstat is at @off bytes into @blkg; otherwise, it
- * is at @off bytes into @blkg's blkg_policy_data of the policy.
- */
- void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
- int off, struct blkg_rwstat_sample *sum)
- {
- struct blkcg_gq *pos_blkg;
- struct cgroup_subsys_state *pos_css;
- unsigned int i;
- lockdep_assert_held(&blkg->q->queue_lock);
- memset(sum, 0, sizeof(*sum));
- rcu_read_lock();
- blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
- struct blkg_rwstat *rwstat;
- if (!pos_blkg->online)
- continue;
- if (pol)
- rwstat = (void *)blkg_to_pd(pos_blkg, pol) + off;
- else
- rwstat = (void *)pos_blkg + off;
- for (i = 0; i < BLKG_RWSTAT_NR; i++)
- sum->cnt[i] += blkg_rwstat_read_counter(rwstat, i);
- }
- rcu_read_unlock();
- }
- EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);
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