diff options
Diffstat (limited to 'block/blk-cgroup.h')
| -rw-r--r-- | block/blk-cgroup.h | 85 |
1 files changed, 46 insertions, 39 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 8056c03a338..d3fd7aa3d2a 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -18,6 +18,7 @@ #include <linux/seq_file.h> #include <linux/radix-tree.h> #include <linux/blkdev.h> +#include <linux/atomic.h> /* Max limits for throttle policy */ #define THROTL_IOPS_MAX UINT_MAX @@ -104,7 +105,7 @@ struct blkcg_gq { struct request_list rl; /* reference count */ - int refcnt; + atomic_t refcnt; /* is this blkg online? protected by both blkcg and q locks */ bool online; @@ -179,22 +180,20 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, void blkg_conf_finish(struct blkg_conf_ctx *ctx); -static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) +static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) { - return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), - struct blkcg, css); + return css ? container_of(css, struct blkcg, css) : NULL; } static inline struct blkcg *task_blkcg(struct task_struct *tsk) { - return container_of(task_subsys_state(tsk, blkio_subsys_id), - struct blkcg, css); + return css_to_blkcg(task_css(tsk, blkio_cgrp_id)); } static inline struct blkcg *bio_blkcg(struct bio *bio) { if (bio && bio->bi_css) - return container_of(bio->bi_css, struct blkcg, css); + return css_to_blkcg(bio->bi_css); return task_blkcg(current); } @@ -206,9 +205,7 @@ static inline struct blkcg *bio_blkcg(struct bio *bio) */ static inline struct blkcg *blkcg_parent(struct blkcg *blkcg) { - struct cgroup *pcg = blkcg->css.cgroup->parent; - - return pcg ? cgroup_to_blkcg(pcg) : NULL; + return css_to_blkcg(blkcg->css.parent); } /** @@ -245,25 +242,28 @@ static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) */ static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) { - int ret; + char *p; - ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); - if (ret) + p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); + if (!p) { strncpy(buf, "<unavailable>", buflen); - return ret; + return -ENAMETOOLONG; + } + + memmove(buf, p, buf + buflen - p); + return 0; } /** * blkg_get - get a blkg reference * @blkg: blkg to get * - * The caller should be holding queue_lock and an existing reference. + * The caller should be holding an existing reference. */ static inline void blkg_get(struct blkcg_gq *blkg) { - lockdep_assert_held(blkg->q->queue_lock); - WARN_ON_ONCE(!blkg->refcnt); - blkg->refcnt++; + WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0); + atomic_inc(&blkg->refcnt); } void __blkg_release_rcu(struct rcu_head *rcu); @@ -271,14 +271,11 @@ void __blkg_release_rcu(struct rcu_head *rcu); /** * blkg_put - put a blkg reference * @blkg: blkg to put - * - * The caller should be holding queue_lock. */ static inline void blkg_put(struct blkcg_gq *blkg) { - lockdep_assert_held(blkg->q->queue_lock); - WARN_ON_ONCE(blkg->refcnt <= 0); - if (!--blkg->refcnt) + WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0); + if (atomic_dec_and_test(&blkg->refcnt)) call_rcu(&blkg->rcu_head, __blkg_release_rcu); } @@ -288,32 +285,33 @@ struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, /** * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants * @d_blkg: loop cursor pointing to the current descendant - * @pos_cgrp: used for iteration + * @pos_css: used for iteration * @p_blkg: target blkg to walk descendants of * * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU * read locked. If called under either blkcg or queue lock, the iteration * is guaranteed to include all and only online blkgs. The caller may - * update @pos_cgrp by calling cgroup_rightmost_descendant() to skip - * subtree. + * update @pos_css by calling css_rightmost_descendant() to skip subtree. + * @p_blkg is included in the iteration and the first node to be visited. */ -#define blkg_for_each_descendant_pre(d_blkg, pos_cgrp, p_blkg) \ - cgroup_for_each_descendant_pre((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \ - if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \ +#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \ + css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \ + if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ (p_blkg)->q, false))) /** * blkg_for_each_descendant_post - post-order walk of a blkg's descendants * @d_blkg: loop cursor pointing to the current descendant - * @pos_cgrp: used for iteration + * @pos_css: used for iteration * @p_blkg: target blkg to walk descendants of * * Similar to blkg_for_each_descendant_pre() but performs post-order - * traversal instead. Synchronization rules are the same. + * traversal instead. Synchronization rules are the same. @p_blkg is + * included in the iteration and the last node to be visited. */ -#define blkg_for_each_descendant_post(d_blkg, pos_cgrp, p_blkg) \ - cgroup_for_each_descendant_post((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \ - if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \ +#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \ + css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \ + if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ (p_blkg)->q, false))) /** @@ -405,6 +403,11 @@ struct request_list *__blk_queue_next_rl(struct request_list *rl, #define blk_queue_for_each_rl(rl, q) \ for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q))) +static inline void blkg_stat_init(struct blkg_stat *stat) +{ + u64_stats_init(&stat->syncp); +} + /** * blkg_stat_add - add a value to a blkg_stat * @stat: target blkg_stat @@ -433,9 +436,9 @@ static inline uint64_t blkg_stat_read(struct blkg_stat *stat) uint64_t v; do { - start = u64_stats_fetch_begin(&stat->syncp); + start = u64_stats_fetch_begin_irq(&stat->syncp); v = stat->cnt; - } while (u64_stats_fetch_retry(&stat->syncp, start)); + } while (u64_stats_fetch_retry_irq(&stat->syncp, start)); return v; } @@ -461,6 +464,11 @@ static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from) blkg_stat_add(to, blkg_stat_read(from)); } +static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat) +{ + u64_stats_init(&rwstat->syncp); +} + /** * blkg_rwstat_add - add a value to a blkg_rwstat * @rwstat: target blkg_rwstat @@ -501,9 +509,9 @@ static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat) struct blkg_rwstat tmp; do { - start = u64_stats_fetch_begin(&rwstat->syncp); + start = u64_stats_fetch_begin_irq(&rwstat->syncp); tmp = *rwstat; - } while (u64_stats_fetch_retry(&rwstat->syncp, start)); + } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start)); return tmp; } @@ -576,7 +584,6 @@ static inline int blkcg_activate_policy(struct request_queue *q, static inline void blkcg_deactivate_policy(struct request_queue *q, const struct blkcg_policy *pol) { } -static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; } static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; } static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, |