1 #ifndef BLK_INTERNAL_H 2 #define BLK_INTERNAL_H 3 4 #include <linux/idr.h> 5 6 /* Amount of time in which a process may batch requests */ 7 #define BLK_BATCH_TIME (HZ/50UL) 8 9 /* Number of requests a "batching" process may submit */ 10 #define BLK_BATCH_REQ 32 11 12 extern struct kmem_cache *blk_requestq_cachep; 13 extern struct kobj_type blk_queue_ktype; 14 extern struct ida blk_queue_ida; 15 16 static inline void __blk_get_queue(struct request_queue *q) 17 { 18 kobject_get(&q->kobj); 19 } 20 21 int blk_init_rl(struct request_list *rl, struct request_queue *q, 22 gfp_t gfp_mask); 23 void blk_exit_rl(struct request_list *rl); 24 void init_request_from_bio(struct request *req, struct bio *bio); 25 void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 26 struct bio *bio); 27 int blk_rq_append_bio(struct request_queue *q, struct request *rq, 28 struct bio *bio); 29 void blk_queue_bypass_start(struct request_queue *q); 30 void blk_queue_bypass_end(struct request_queue *q); 31 void blk_dequeue_request(struct request *rq); 32 void __blk_queue_free_tags(struct request_queue *q); 33 bool __blk_end_bidi_request(struct request *rq, int error, 34 unsigned int nr_bytes, unsigned int bidi_bytes); 35 36 void blk_rq_timed_out_timer(unsigned long data); 37 void blk_delete_timer(struct request *); 38 void blk_add_timer(struct request *); 39 40 /* 41 * Internal atomic flags for request handling 42 */ 43 enum rq_atomic_flags { 44 REQ_ATOM_COMPLETE = 0, 45 }; 46 47 /* 48 * EH timer and IO completion will both attempt to 'grab' the request, make 49 * sure that only one of them succeeds 50 */ 51 static inline int blk_mark_rq_complete(struct request *rq) 52 { 53 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 54 } 55 56 static inline void blk_clear_rq_complete(struct request *rq) 57 { 58 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 59 } 60 61 /* 62 * Internal elevator interface 63 */ 64 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) 65 66 void blk_insert_flush(struct request *rq); 67 void blk_abort_flushes(struct request_queue *q); 68 69 static inline struct request *__elv_next_request(struct request_queue *q) 70 { 71 struct request *rq; 72 73 while (1) { 74 if (!list_empty(&q->queue_head)) { 75 rq = list_entry_rq(q->queue_head.next); 76 return rq; 77 } 78 79 /* 80 * Flush request is running and flush request isn't queueable 81 * in the drive, we can hold the queue till flush request is 82 * finished. Even we don't do this, driver can't dispatch next 83 * requests and will requeue them. And this can improve 84 * throughput too. For example, we have request flush1, write1, 85 * flush 2. flush1 is dispatched, then queue is hold, write1 86 * isn't inserted to queue. After flush1 is finished, flush2 87 * will be dispatched. Since disk cache is already clean, 88 * flush2 will be finished very soon, so looks like flush2 is 89 * folded to flush1. 90 * Since the queue is hold, a flag is set to indicate the queue 91 * should be restarted later. Please see flush_end_io() for 92 * details. 93 */ 94 if (q->flush_pending_idx != q->flush_running_idx && 95 !queue_flush_queueable(q)) { 96 q->flush_queue_delayed = 1; 97 return NULL; 98 } 99 if (unlikely(blk_queue_dying(q)) || 100 !q->elevator->type->ops.elevator_dispatch_fn(q, 0)) 101 return NULL; 102 } 103 } 104 105 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 106 { 107 struct elevator_queue *e = q->elevator; 108 109 if (e->type->ops.elevator_activate_req_fn) 110 e->type->ops.elevator_activate_req_fn(q, rq); 111 } 112 113 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 114 { 115 struct elevator_queue *e = q->elevator; 116 117 if (e->type->ops.elevator_deactivate_req_fn) 118 e->type->ops.elevator_deactivate_req_fn(q, rq); 119 } 120 121 #ifdef CONFIG_FAIL_IO_TIMEOUT 122 int blk_should_fake_timeout(struct request_queue *); 123 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 124 ssize_t part_timeout_store(struct device *, struct device_attribute *, 125 const char *, size_t); 126 #else 127 static inline int blk_should_fake_timeout(struct request_queue *q) 128 { 129 return 0; 130 } 131 #endif 132 133 int ll_back_merge_fn(struct request_queue *q, struct request *req, 134 struct bio *bio); 135 int ll_front_merge_fn(struct request_queue *q, struct request *req, 136 struct bio *bio); 137 int attempt_back_merge(struct request_queue *q, struct request *rq); 138 int attempt_front_merge(struct request_queue *q, struct request *rq); 139 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 140 struct request *next); 141 void blk_recalc_rq_segments(struct request *rq); 142 void blk_rq_set_mixed_merge(struct request *rq); 143 bool blk_rq_merge_ok(struct request *rq, struct bio *bio); 144 int blk_try_merge(struct request *rq, struct bio *bio); 145 146 void blk_queue_congestion_threshold(struct request_queue *q); 147 148 void __blk_run_queue_uncond(struct request_queue *q); 149 150 int blk_dev_init(void); 151 152 153 /* 154 * Return the threshold (number of used requests) at which the queue is 155 * considered to be congested. It include a little hysteresis to keep the 156 * context switch rate down. 157 */ 158 static inline int queue_congestion_on_threshold(struct request_queue *q) 159 { 160 return q->nr_congestion_on; 161 } 162 163 /* 164 * The threshold at which a queue is considered to be uncongested 165 */ 166 static inline int queue_congestion_off_threshold(struct request_queue *q) 167 { 168 return q->nr_congestion_off; 169 } 170 171 /* 172 * Contribute to IO statistics IFF: 173 * 174 * a) it's attached to a gendisk, and 175 * b) the queue had IO stats enabled when this request was started, and 176 * c) it's a file system request 177 */ 178 static inline int blk_do_io_stat(struct request *rq) 179 { 180 return rq->rq_disk && 181 (rq->cmd_flags & REQ_IO_STAT) && 182 (rq->cmd_type == REQ_TYPE_FS); 183 } 184 185 /* 186 * Internal io_context interface 187 */ 188 void get_io_context(struct io_context *ioc); 189 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q); 190 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q, 191 gfp_t gfp_mask); 192 void ioc_clear_queue(struct request_queue *q); 193 194 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node); 195 196 /** 197 * create_io_context - try to create task->io_context 198 * @gfp_mask: allocation mask 199 * @node: allocation node 200 * 201 * If %current->io_context is %NULL, allocate a new io_context and install 202 * it. Returns the current %current->io_context which may be %NULL if 203 * allocation failed. 204 * 205 * Note that this function can't be called with IRQ disabled because 206 * task_lock which protects %current->io_context is IRQ-unsafe. 207 */ 208 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node) 209 { 210 WARN_ON_ONCE(irqs_disabled()); 211 if (unlikely(!current->io_context)) 212 create_task_io_context(current, gfp_mask, node); 213 return current->io_context; 214 } 215 216 /* 217 * Internal throttling interface 218 */ 219 #ifdef CONFIG_BLK_DEV_THROTTLING 220 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio); 221 extern void blk_throtl_drain(struct request_queue *q); 222 extern int blk_throtl_init(struct request_queue *q); 223 extern void blk_throtl_exit(struct request_queue *q); 224 #else /* CONFIG_BLK_DEV_THROTTLING */ 225 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio) 226 { 227 return false; 228 } 229 static inline void blk_throtl_drain(struct request_queue *q) { } 230 static inline int blk_throtl_init(struct request_queue *q) { return 0; } 231 static inline void blk_throtl_exit(struct request_queue *q) { } 232 #endif /* CONFIG_BLK_DEV_THROTTLING */ 233 234 #endif /* BLK_INTERNAL_H */ 235