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 if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) 66 return NULL; 67 } 68 } 69 70 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 71 { 72 struct elevator_queue *e = q->elevator; 73 74 if (e->ops->elevator_activate_req_fn) 75 e->ops->elevator_activate_req_fn(q, rq); 76 } 77 78 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 79 { 80 struct elevator_queue *e = q->elevator; 81 82 if (e->ops->elevator_deactivate_req_fn) 83 e->ops->elevator_deactivate_req_fn(q, rq); 84 } 85 86 #ifdef CONFIG_FAIL_IO_TIMEOUT 87 int blk_should_fake_timeout(struct request_queue *); 88 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 89 ssize_t part_timeout_store(struct device *, struct device_attribute *, 90 const char *, size_t); 91 #else 92 static inline int blk_should_fake_timeout(struct request_queue *q) 93 { 94 return 0; 95 } 96 #endif 97 98 struct io_context *current_io_context(gfp_t gfp_flags, int node); 99 100 int ll_back_merge_fn(struct request_queue *q, struct request *req, 101 struct bio *bio); 102 int ll_front_merge_fn(struct request_queue *q, struct request *req, 103 struct bio *bio); 104 int attempt_back_merge(struct request_queue *q, struct request *rq); 105 int attempt_front_merge(struct request_queue *q, struct request *rq); 106 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 107 struct request *next); 108 void blk_recalc_rq_segments(struct request *rq); 109 void blk_rq_set_mixed_merge(struct request *rq); 110 111 void blk_queue_congestion_threshold(struct request_queue *q); 112 113 int blk_dev_init(void); 114 115 void elv_quiesce_start(struct request_queue *q); 116 void elv_quiesce_end(struct request_queue *q); 117 118 119 /* 120 * Return the threshold (number of used requests) at which the queue is 121 * considered to be congested. It include a little hysteresis to keep the 122 * context switch rate down. 123 */ 124 static inline int queue_congestion_on_threshold(struct request_queue *q) 125 { 126 return q->nr_congestion_on; 127 } 128 129 /* 130 * The threshold at which a queue is considered to be uncongested 131 */ 132 static inline int queue_congestion_off_threshold(struct request_queue *q) 133 { 134 return q->nr_congestion_off; 135 } 136 137 static inline int blk_cpu_to_group(int cpu) 138 { 139 int group = NR_CPUS; 140 #ifdef CONFIG_SCHED_MC 141 const struct cpumask *mask = cpu_coregroup_mask(cpu); 142 group = cpumask_first(mask); 143 #elif defined(CONFIG_SCHED_SMT) 144 group = cpumask_first(topology_thread_cpumask(cpu)); 145 #else 146 return cpu; 147 #endif 148 if (likely(group < NR_CPUS)) 149 return group; 150 return cpu; 151 } 152 153 /* 154 * Contribute to IO statistics IFF: 155 * 156 * a) it's attached to a gendisk, and 157 * b) the queue had IO stats enabled when this request was started, and 158 * c) it's a file system request or a discard request 159 */ 160 static inline int blk_do_io_stat(struct request *rq) 161 { 162 return rq->rq_disk && 163 (rq->cmd_flags & REQ_IO_STAT) && 164 (rq->cmd_type == REQ_TYPE_FS || 165 (rq->cmd_flags & REQ_DISCARD)); 166 } 167 168 #endif 169