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_drain_queue(struct request_queue *q, bool drain_all); 19 void blk_dequeue_request(struct request *rq); 20 void __blk_queue_free_tags(struct request_queue *q); 21 bool __blk_end_bidi_request(struct request *rq, int error, 22 unsigned int nr_bytes, unsigned int bidi_bytes); 23 24 void blk_rq_timed_out_timer(unsigned long data); 25 void blk_delete_timer(struct request *); 26 void blk_add_timer(struct request *); 27 void __generic_unplug_device(struct request_queue *); 28 29 /* 30 * Internal atomic flags for request handling 31 */ 32 enum rq_atomic_flags { 33 REQ_ATOM_COMPLETE = 0, 34 }; 35 36 /* 37 * EH timer and IO completion will both attempt to 'grab' the request, make 38 * sure that only one of them succeeds 39 */ 40 static inline int blk_mark_rq_complete(struct request *rq) 41 { 42 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 43 } 44 45 static inline void blk_clear_rq_complete(struct request *rq) 46 { 47 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 48 } 49 50 /* 51 * Internal elevator interface 52 */ 53 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) 54 55 void blk_insert_flush(struct request *rq); 56 void blk_abort_flushes(struct request_queue *q); 57 58 static inline struct request *__elv_next_request(struct request_queue *q) 59 { 60 struct request *rq; 61 62 while (1) { 63 if (!list_empty(&q->queue_head)) { 64 rq = list_entry_rq(q->queue_head.next); 65 return rq; 66 } 67 68 /* 69 * Flush request is running and flush request isn't queueable 70 * in the drive, we can hold the queue till flush request is 71 * finished. Even we don't do this, driver can't dispatch next 72 * requests and will requeue them. And this can improve 73 * throughput too. For example, we have request flush1, write1, 74 * flush 2. flush1 is dispatched, then queue is hold, write1 75 * isn't inserted to queue. After flush1 is finished, flush2 76 * will be dispatched. Since disk cache is already clean, 77 * flush2 will be finished very soon, so looks like flush2 is 78 * folded to flush1. 79 * Since the queue is hold, a flag is set to indicate the queue 80 * should be restarted later. Please see flush_end_io() for 81 * details. 82 */ 83 if (q->flush_pending_idx != q->flush_running_idx && 84 !queue_flush_queueable(q)) { 85 q->flush_queue_delayed = 1; 86 return NULL; 87 } 88 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) || 89 !q->elevator->ops->elevator_dispatch_fn(q, 0)) 90 return NULL; 91 } 92 } 93 94 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 95 { 96 struct elevator_queue *e = q->elevator; 97 98 if (e->ops->elevator_activate_req_fn) 99 e->ops->elevator_activate_req_fn(q, rq); 100 } 101 102 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 103 { 104 struct elevator_queue *e = q->elevator; 105 106 if (e->ops->elevator_deactivate_req_fn) 107 e->ops->elevator_deactivate_req_fn(q, rq); 108 } 109 110 #ifdef CONFIG_FAIL_IO_TIMEOUT 111 int blk_should_fake_timeout(struct request_queue *); 112 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 113 ssize_t part_timeout_store(struct device *, struct device_attribute *, 114 const char *, size_t); 115 #else 116 static inline int blk_should_fake_timeout(struct request_queue *q) 117 { 118 return 0; 119 } 120 #endif 121 122 struct io_context *current_io_context(gfp_t gfp_flags, int node); 123 124 int ll_back_merge_fn(struct request_queue *q, struct request *req, 125 struct bio *bio); 126 int ll_front_merge_fn(struct request_queue *q, struct request *req, 127 struct bio *bio); 128 int attempt_back_merge(struct request_queue *q, struct request *rq); 129 int attempt_front_merge(struct request_queue *q, struct request *rq); 130 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 131 struct request *next); 132 void blk_recalc_rq_segments(struct request *rq); 133 void blk_rq_set_mixed_merge(struct request *rq); 134 135 void blk_queue_congestion_threshold(struct request_queue *q); 136 137 int blk_dev_init(void); 138 139 void elv_quiesce_start(struct request_queue *q); 140 void elv_quiesce_end(struct request_queue *q); 141 142 143 /* 144 * Return the threshold (number of used requests) at which the queue is 145 * considered to be congested. It include a little hysteresis to keep the 146 * context switch rate down. 147 */ 148 static inline int queue_congestion_on_threshold(struct request_queue *q) 149 { 150 return q->nr_congestion_on; 151 } 152 153 /* 154 * The threshold at which a queue is considered to be uncongested 155 */ 156 static inline int queue_congestion_off_threshold(struct request_queue *q) 157 { 158 return q->nr_congestion_off; 159 } 160 161 static inline int blk_cpu_to_group(int cpu) 162 { 163 int group = NR_CPUS; 164 #ifdef CONFIG_SCHED_MC 165 const struct cpumask *mask = cpu_coregroup_mask(cpu); 166 group = cpumask_first(mask); 167 #elif defined(CONFIG_SCHED_SMT) 168 group = cpumask_first(topology_thread_cpumask(cpu)); 169 #else 170 return cpu; 171 #endif 172 if (likely(group < NR_CPUS)) 173 return group; 174 return cpu; 175 } 176 177 /* 178 * Contribute to IO statistics IFF: 179 * 180 * a) it's attached to a gendisk, and 181 * b) the queue had IO stats enabled when this request was started, and 182 * c) it's a file system request or a discard request 183 */ 184 static inline int blk_do_io_stat(struct request *rq) 185 { 186 return rq->rq_disk && 187 (rq->cmd_flags & REQ_IO_STAT) && 188 (rq->cmd_type == REQ_TYPE_FS || 189 (rq->cmd_flags & REQ_DISCARD)); 190 } 191 192 #ifdef CONFIG_BLK_DEV_THROTTLING 193 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio); 194 extern void blk_throtl_drain(struct request_queue *q); 195 extern int blk_throtl_init(struct request_queue *q); 196 extern void blk_throtl_exit(struct request_queue *q); 197 extern void blk_throtl_release(struct request_queue *q); 198 #else /* CONFIG_BLK_DEV_THROTTLING */ 199 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio) 200 { 201 return false; 202 } 203 static inline void blk_throtl_drain(struct request_queue *q) { } 204 static inline int blk_throtl_init(struct request_queue *q) { return 0; } 205 static inline void blk_throtl_exit(struct request_queue *q) { } 206 static inline void blk_throtl_release(struct request_queue *q) { } 207 #endif /* CONFIG_BLK_DEV_THROTTLING */ 208 209 #endif /* BLK_INTERNAL_H */ 210