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 bool __blk_end_bidi_request(struct request *rq, int error, 21 unsigned int nr_bytes, unsigned int bidi_bytes); 22 23 void blk_rq_timed_out_timer(unsigned long data); 24 void blk_delete_timer(struct request *); 25 void blk_add_timer(struct request *); 26 void __generic_unplug_device(struct request_queue *); 27 28 /* 29 * Internal atomic flags for request handling 30 */ 31 enum rq_atomic_flags { 32 REQ_ATOM_COMPLETE = 0, 33 }; 34 35 /* 36 * EH timer and IO completion will both attempt to 'grab' the request, make 37 * sure that only one of them succeeds 38 */ 39 static inline int blk_mark_rq_complete(struct request *rq) 40 { 41 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 42 } 43 44 static inline void blk_clear_rq_complete(struct request *rq) 45 { 46 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 47 } 48 49 /* 50 * Internal elevator interface 51 */ 52 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) 53 54 void blk_insert_flush(struct request *rq); 55 void blk_abort_flushes(struct request_queue *q); 56 57 static inline struct request *__elv_next_request(struct request_queue *q) 58 { 59 struct request *rq; 60 61 while (1) { 62 if (!list_empty(&q->queue_head)) { 63 rq = list_entry_rq(q->queue_head.next); 64 return rq; 65 } 66 67 /* 68 * Flush request is running and flush request isn't queueable 69 * in the drive, we can hold the queue till flush request is 70 * finished. Even we don't do this, driver can't dispatch next 71 * requests and will requeue them. And this can improve 72 * throughput too. For example, we have request flush1, write1, 73 * flush 2. flush1 is dispatched, then queue is hold, write1 74 * isn't inserted to queue. After flush1 is finished, flush2 75 * will be dispatched. Since disk cache is already clean, 76 * flush2 will be finished very soon, so looks like flush2 is 77 * folded to flush1. 78 * Since the queue is hold, a flag is set to indicate the queue 79 * should be restarted later. Please see flush_end_io() for 80 * details. 81 */ 82 if (q->flush_pending_idx != q->flush_running_idx && 83 !queue_flush_queueable(q)) { 84 q->flush_queue_delayed = 1; 85 return NULL; 86 } 87 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) || 88 !q->elevator->ops->elevator_dispatch_fn(q, 0)) 89 return NULL; 90 } 91 } 92 93 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 94 { 95 struct elevator_queue *e = q->elevator; 96 97 if (e->ops->elevator_activate_req_fn) 98 e->ops->elevator_activate_req_fn(q, rq); 99 } 100 101 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 102 { 103 struct elevator_queue *e = q->elevator; 104 105 if (e->ops->elevator_deactivate_req_fn) 106 e->ops->elevator_deactivate_req_fn(q, rq); 107 } 108 109 #ifdef CONFIG_FAIL_IO_TIMEOUT 110 int blk_should_fake_timeout(struct request_queue *); 111 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 112 ssize_t part_timeout_store(struct device *, struct device_attribute *, 113 const char *, size_t); 114 #else 115 static inline int blk_should_fake_timeout(struct request_queue *q) 116 { 117 return 0; 118 } 119 #endif 120 121 struct io_context *current_io_context(gfp_t gfp_flags, int node); 122 123 int ll_back_merge_fn(struct request_queue *q, struct request *req, 124 struct bio *bio); 125 int ll_front_merge_fn(struct request_queue *q, struct request *req, 126 struct bio *bio); 127 int attempt_back_merge(struct request_queue *q, struct request *rq); 128 int attempt_front_merge(struct request_queue *q, struct request *rq); 129 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 130 struct request *next); 131 void blk_recalc_rq_segments(struct request *rq); 132 void blk_rq_set_mixed_merge(struct request *rq); 133 134 void blk_queue_congestion_threshold(struct request_queue *q); 135 136 int blk_dev_init(void); 137 138 void elv_quiesce_start(struct request_queue *q); 139 void elv_quiesce_end(struct request_queue *q); 140 141 142 /* 143 * Return the threshold (number of used requests) at which the queue is 144 * considered to be congested. It include a little hysteresis to keep the 145 * context switch rate down. 146 */ 147 static inline int queue_congestion_on_threshold(struct request_queue *q) 148 { 149 return q->nr_congestion_on; 150 } 151 152 /* 153 * The threshold at which a queue is considered to be uncongested 154 */ 155 static inline int queue_congestion_off_threshold(struct request_queue *q) 156 { 157 return q->nr_congestion_off; 158 } 159 160 static inline int blk_cpu_to_group(int cpu) 161 { 162 int group = NR_CPUS; 163 #ifdef CONFIG_SCHED_MC 164 const struct cpumask *mask = cpu_coregroup_mask(cpu); 165 group = cpumask_first(mask); 166 #elif defined(CONFIG_SCHED_SMT) 167 group = cpumask_first(topology_thread_cpumask(cpu)); 168 #else 169 return cpu; 170 #endif 171 if (likely(group < NR_CPUS)) 172 return group; 173 return cpu; 174 } 175 176 /* 177 * Contribute to IO statistics IFF: 178 * 179 * a) it's attached to a gendisk, and 180 * b) the queue had IO stats enabled when this request was started, and 181 * c) it's a file system request or a discard request 182 */ 183 static inline int blk_do_io_stat(struct request *rq) 184 { 185 return rq->rq_disk && 186 (rq->cmd_flags & REQ_IO_STAT) && 187 (rq->cmd_type == REQ_TYPE_FS || 188 (rq->cmd_flags & REQ_DISCARD)); 189 } 190 191 #endif 192