1 #ifndef BLK_INTERNAL_H 2 #define BLK_INTERNAL_H 3 4 /* Amount of time in which a process may batch requests */ 5 #define BLK_BATCH_TIME (HZ/50UL) 6 7 /* Number of requests a "batching" process may submit */ 8 #define BLK_BATCH_REQ 32 9 10 extern struct kmem_cache *blk_requestq_cachep; 11 extern struct kobj_type blk_queue_ktype; 12 13 void init_request_from_bio(struct request *req, struct bio *bio); 14 void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 15 struct bio *bio); 16 int blk_rq_append_bio(struct request_queue *q, struct request *rq, 17 struct bio *bio); 18 void blk_dequeue_request(struct request *rq); 19 void __blk_queue_free_tags(struct request_queue *q); 20 21 void blk_rq_timed_out_timer(unsigned long data); 22 void blk_delete_timer(struct request *); 23 void blk_add_timer(struct request *); 24 void __generic_unplug_device(struct request_queue *); 25 26 /* 27 * Internal atomic flags for request handling 28 */ 29 enum rq_atomic_flags { 30 REQ_ATOM_COMPLETE = 0, 31 }; 32 33 /* 34 * EH timer and IO completion will both attempt to 'grab' the request, make 35 * sure that only one of them succeeds 36 */ 37 static inline int blk_mark_rq_complete(struct request *rq) 38 { 39 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 40 } 41 42 static inline void blk_clear_rq_complete(struct request *rq) 43 { 44 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 45 } 46 47 /* 48 * Internal elevator interface 49 */ 50 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) 51 52 void blk_insert_flush(struct request *rq); 53 void blk_abort_flushes(struct request_queue *q); 54 55 static inline struct request *__elv_next_request(struct request_queue *q) 56 { 57 struct request *rq; 58 59 while (1) { 60 if (!list_empty(&q->queue_head)) { 61 rq = list_entry_rq(q->queue_head.next); 62 return rq; 63 } 64 65 /* 66 * Flush request is running and flush request isn't queueable 67 * in the drive, we can hold the queue till flush request is 68 * finished. Even we don't do this, driver can't dispatch next 69 * requests and will requeue them. And this can improve 70 * throughput too. For example, we have request flush1, write1, 71 * flush 2. flush1 is dispatched, then queue is hold, write1 72 * isn't inserted to queue. After flush1 is finished, flush2 73 * will be dispatched. Since disk cache is already clean, 74 * flush2 will be finished very soon, so looks like flush2 is 75 * folded to flush1. 76 * Since the queue is hold, a flag is set to indicate the queue 77 * should be restarted later. Please see flush_end_io() for 78 * details. 79 */ 80 if (q->flush_pending_idx != q->flush_running_idx && 81 !queue_flush_queueable(q)) { 82 q->flush_queue_delayed = 1; 83 return NULL; 84 } 85 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) || 86 !q->elevator->ops->elevator_dispatch_fn(q, 0)) 87 return NULL; 88 } 89 } 90 91 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 92 { 93 struct elevator_queue *e = q->elevator; 94 95 if (e->ops->elevator_activate_req_fn) 96 e->ops->elevator_activate_req_fn(q, rq); 97 } 98 99 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 100 { 101 struct elevator_queue *e = q->elevator; 102 103 if (e->ops->elevator_deactivate_req_fn) 104 e->ops->elevator_deactivate_req_fn(q, rq); 105 } 106 107 #ifdef CONFIG_FAIL_IO_TIMEOUT 108 int blk_should_fake_timeout(struct request_queue *); 109 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 110 ssize_t part_timeout_store(struct device *, struct device_attribute *, 111 const char *, size_t); 112 #else 113 static inline int blk_should_fake_timeout(struct request_queue *q) 114 { 115 return 0; 116 } 117 #endif 118 119 struct io_context *current_io_context(gfp_t gfp_flags, int node); 120 121 int ll_back_merge_fn(struct request_queue *q, struct request *req, 122 struct bio *bio); 123 int ll_front_merge_fn(struct request_queue *q, struct request *req, 124 struct bio *bio); 125 int attempt_back_merge(struct request_queue *q, struct request *rq); 126 int attempt_front_merge(struct request_queue *q, struct request *rq); 127 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 128 struct request *next); 129 void blk_recalc_rq_segments(struct request *rq); 130 void blk_rq_set_mixed_merge(struct request *rq); 131 132 void blk_queue_congestion_threshold(struct request_queue *q); 133 134 int blk_dev_init(void); 135 136 void elv_quiesce_start(struct request_queue *q); 137 void elv_quiesce_end(struct request_queue *q); 138 139 140 /* 141 * Return the threshold (number of used requests) at which the queue is 142 * considered to be congested. It include a little hysteresis to keep the 143 * context switch rate down. 144 */ 145 static inline int queue_congestion_on_threshold(struct request_queue *q) 146 { 147 return q->nr_congestion_on; 148 } 149 150 /* 151 * The threshold at which a queue is considered to be uncongested 152 */ 153 static inline int queue_congestion_off_threshold(struct request_queue *q) 154 { 155 return q->nr_congestion_off; 156 } 157 158 static inline int blk_cpu_to_group(int cpu) 159 { 160 int group = NR_CPUS; 161 #ifdef CONFIG_SCHED_MC 162 const struct cpumask *mask = cpu_coregroup_mask(cpu); 163 group = cpumask_first(mask); 164 #elif defined(CONFIG_SCHED_SMT) 165 group = cpumask_first(topology_thread_cpumask(cpu)); 166 #else 167 return cpu; 168 #endif 169 if (likely(group < NR_CPUS)) 170 return group; 171 return cpu; 172 } 173 174 /* 175 * Contribute to IO statistics IFF: 176 * 177 * a) it's attached to a gendisk, and 178 * b) the queue had IO stats enabled when this request was started, and 179 * c) it's a file system request or a discard request 180 */ 181 static inline int blk_do_io_stat(struct request *rq) 182 { 183 return rq->rq_disk && 184 (rq->cmd_flags & REQ_IO_STAT) && 185 (rq->cmd_type == REQ_TYPE_FS || 186 (rq->cmd_flags & REQ_DISCARD)); 187 } 188 189 #endif 190