diff options
Diffstat (limited to 'block/blk.h')
-rw-r--r-- | block/blk.h | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/block/blk.h b/block/blk.h new file mode 100644 index 00000000..d6586287 --- /dev/null +++ b/block/blk.h @@ -0,0 +1,189 @@ +#ifndef BLK_INTERNAL_H +#define BLK_INTERNAL_H + +/* Amount of time in which a process may batch requests */ +#define BLK_BATCH_TIME (HZ/50UL) + +/* Number of requests a "batching" process may submit */ +#define BLK_BATCH_REQ 32 + +extern struct kmem_cache *blk_requestq_cachep; +extern struct kobj_type blk_queue_ktype; + +void init_request_from_bio(struct request *req, struct bio *bio); +void blk_rq_bio_prep(struct request_queue *q, struct request *rq, + struct bio *bio); +int blk_rq_append_bio(struct request_queue *q, struct request *rq, + struct bio *bio); +void blk_dequeue_request(struct request *rq); +void __blk_queue_free_tags(struct request_queue *q); + +void blk_rq_timed_out_timer(unsigned long data); +void blk_delete_timer(struct request *); +void blk_add_timer(struct request *); +void __generic_unplug_device(struct request_queue *); + +/* + * Internal atomic flags for request handling + */ +enum rq_atomic_flags { + REQ_ATOM_COMPLETE = 0, +}; + +/* + * EH timer and IO completion will both attempt to 'grab' the request, make + * sure that only one of them succeeds + */ +static inline int blk_mark_rq_complete(struct request *rq) +{ + return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); +} + +static inline void blk_clear_rq_complete(struct request *rq) +{ + clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); +} + +/* + * Internal elevator interface + */ +#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) + +void blk_insert_flush(struct request *rq); +void blk_abort_flushes(struct request_queue *q); + +static inline struct request *__elv_next_request(struct request_queue *q) +{ + struct request *rq; + + while (1) { + if (!list_empty(&q->queue_head)) { + rq = list_entry_rq(q->queue_head.next); + return rq; + } + + /* + * Flush request is running and flush request isn't queueable + * in the drive, we can hold the queue till flush request is + * finished. Even we don't do this, driver can't dispatch next + * requests and will requeue them. And this can improve + * throughput too. For example, we have request flush1, write1, + * flush 2. flush1 is dispatched, then queue is hold, write1 + * isn't inserted to queue. After flush1 is finished, flush2 + * will be dispatched. Since disk cache is already clean, + * flush2 will be finished very soon, so looks like flush2 is + * folded to flush1. + * Since the queue is hold, a flag is set to indicate the queue + * should be restarted later. Please see flush_end_io() for + * details. + */ + if (q->flush_pending_idx != q->flush_running_idx && + !queue_flush_queueable(q)) { + q->flush_queue_delayed = 1; + return NULL; + } + if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) || + !q->elevator->ops->elevator_dispatch_fn(q, 0)) + return NULL; + } +} + +static inline void elv_activate_rq(struct request_queue *q, struct request *rq) +{ + struct elevator_queue *e = q->elevator; + + if (e->ops->elevator_activate_req_fn) + e->ops->elevator_activate_req_fn(q, rq); +} + +static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) +{ + struct elevator_queue *e = q->elevator; + + if (e->ops->elevator_deactivate_req_fn) + e->ops->elevator_deactivate_req_fn(q, rq); +} + +#ifdef CONFIG_FAIL_IO_TIMEOUT +int blk_should_fake_timeout(struct request_queue *); +ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); +ssize_t part_timeout_store(struct device *, struct device_attribute *, + const char *, size_t); +#else +static inline int blk_should_fake_timeout(struct request_queue *q) +{ + return 0; +} +#endif + +struct io_context *current_io_context(gfp_t gfp_flags, int node); + +int ll_back_merge_fn(struct request_queue *q, struct request *req, + struct bio *bio); +int ll_front_merge_fn(struct request_queue *q, struct request *req, + struct bio *bio); +int attempt_back_merge(struct request_queue *q, struct request *rq); +int attempt_front_merge(struct request_queue *q, struct request *rq); +int blk_attempt_req_merge(struct request_queue *q, struct request *rq, + struct request *next); +void blk_recalc_rq_segments(struct request *rq); +void blk_rq_set_mixed_merge(struct request *rq); + +void blk_queue_congestion_threshold(struct request_queue *q); + +int blk_dev_init(void); + +void elv_quiesce_start(struct request_queue *q); +void elv_quiesce_end(struct request_queue *q); + + +/* + * Return the threshold (number of used requests) at which the queue is + * considered to be congested. It include a little hysteresis to keep the + * context switch rate down. + */ +static inline int queue_congestion_on_threshold(struct request_queue *q) +{ + return q->nr_congestion_on; +} + +/* + * The threshold at which a queue is considered to be uncongested + */ +static inline int queue_congestion_off_threshold(struct request_queue *q) +{ + return q->nr_congestion_off; +} + +static inline int blk_cpu_to_group(int cpu) +{ + int group = NR_CPUS; +#ifdef CONFIG_SCHED_MC + const struct cpumask *mask = cpu_coregroup_mask(cpu); + group = cpumask_first(mask); +#elif defined(CONFIG_SCHED_SMT) + group = cpumask_first(topology_thread_cpumask(cpu)); +#else + return cpu; +#endif + if (likely(group < NR_CPUS)) + return group; + return cpu; +} + +/* + * Contribute to IO statistics IFF: + * + * a) it's attached to a gendisk, and + * b) the queue had IO stats enabled when this request was started, and + * c) it's a file system request or a discard request + */ +static inline int blk_do_io_stat(struct request *rq) +{ + return rq->rq_disk && + (rq->cmd_flags & REQ_IO_STAT) && + (rq->cmd_type == REQ_TYPE_FS || + (rq->cmd_flags & REQ_DISCARD)); +} + +#endif |