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 /* Max future timer expiry for timeouts */ 13 #define BLK_MAX_TIMEOUT (5 * HZ) 14 15 extern struct kmem_cache *blk_requestq_cachep; 16 extern struct kmem_cache *request_cachep; 17 extern struct kobj_type blk_queue_ktype; 18 extern struct ida blk_queue_ida; 19 20 static inline void __blk_get_queue(struct request_queue *q) 21 { 22 kobject_get(&q->kobj); 23 } 24 25 int blk_init_rl(struct request_list *rl, struct request_queue *q, 26 gfp_t gfp_mask); 27 void blk_exit_rl(struct request_list *rl); 28 void init_request_from_bio(struct request *req, struct bio *bio); 29 void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 30 struct bio *bio); 31 int blk_rq_append_bio(struct request_queue *q, struct request *rq, 32 struct bio *bio); 33 void blk_queue_bypass_start(struct request_queue *q); 34 void blk_queue_bypass_end(struct request_queue *q); 35 void blk_dequeue_request(struct request *rq); 36 void __blk_queue_free_tags(struct request_queue *q); 37 bool __blk_end_bidi_request(struct request *rq, int error, 38 unsigned int nr_bytes, unsigned int bidi_bytes); 39 40 void blk_rq_timed_out_timer(unsigned long data); 41 void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout, 42 unsigned int *next_set); 43 unsigned long blk_rq_timeout(unsigned long timeout); 44 void blk_add_timer(struct request *req); 45 void blk_delete_timer(struct request *); 46 47 48 bool bio_attempt_front_merge(struct request_queue *q, struct request *req, 49 struct bio *bio); 50 bool bio_attempt_back_merge(struct request_queue *q, struct request *req, 51 struct bio *bio); 52 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, 53 unsigned int *request_count); 54 55 void blk_account_io_start(struct request *req, bool new_io); 56 void blk_account_io_completion(struct request *req, unsigned int bytes); 57 void blk_account_io_done(struct request *req); 58 59 /* 60 * Internal atomic flags for request handling 61 */ 62 enum rq_atomic_flags { 63 REQ_ATOM_COMPLETE = 0, 64 REQ_ATOM_STARTED, 65 }; 66 67 /* 68 * EH timer and IO completion will both attempt to 'grab' the request, make 69 * sure that only one of them succeeds 70 */ 71 static inline int blk_mark_rq_complete(struct request *rq) 72 { 73 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 74 } 75 76 static inline void blk_clear_rq_complete(struct request *rq) 77 { 78 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 79 } 80 81 /* 82 * Internal elevator interface 83 */ 84 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED) 85 86 void blk_insert_flush(struct request *rq); 87 void blk_abort_flushes(struct request_queue *q); 88 89 static inline struct request *__elv_next_request(struct request_queue *q) 90 { 91 struct request *rq; 92 93 while (1) { 94 if (!list_empty(&q->queue_head)) { 95 rq = list_entry_rq(q->queue_head.next); 96 return rq; 97 } 98 99 /* 100 * Flush request is running and flush request isn't queueable 101 * in the drive, we can hold the queue till flush request is 102 * finished. Even we don't do this, driver can't dispatch next 103 * requests and will requeue them. And this can improve 104 * throughput too. For example, we have request flush1, write1, 105 * flush 2. flush1 is dispatched, then queue is hold, write1 106 * isn't inserted to queue. After flush1 is finished, flush2 107 * will be dispatched. Since disk cache is already clean, 108 * flush2 will be finished very soon, so looks like flush2 is 109 * folded to flush1. 110 * Since the queue is hold, a flag is set to indicate the queue 111 * should be restarted later. Please see flush_end_io() for 112 * details. 113 */ 114 if (q->flush_pending_idx != q->flush_running_idx && 115 !queue_flush_queueable(q)) { 116 q->flush_queue_delayed = 1; 117 return NULL; 118 } 119 if (unlikely(blk_queue_bypass(q)) || 120 !q->elevator->type->ops.elevator_dispatch_fn(q, 0)) 121 return NULL; 122 } 123 } 124 125 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 126 { 127 struct elevator_queue *e = q->elevator; 128 129 if (e->type->ops.elevator_activate_req_fn) 130 e->type->ops.elevator_activate_req_fn(q, rq); 131 } 132 133 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 134 { 135 struct elevator_queue *e = q->elevator; 136 137 if (e->type->ops.elevator_deactivate_req_fn) 138 e->type->ops.elevator_deactivate_req_fn(q, rq); 139 } 140 141 #ifdef CONFIG_FAIL_IO_TIMEOUT 142 int blk_should_fake_timeout(struct request_queue *); 143 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 144 ssize_t part_timeout_store(struct device *, struct device_attribute *, 145 const char *, size_t); 146 #else 147 static inline int blk_should_fake_timeout(struct request_queue *q) 148 { 149 return 0; 150 } 151 #endif 152 153 int ll_back_merge_fn(struct request_queue *q, struct request *req, 154 struct bio *bio); 155 int ll_front_merge_fn(struct request_queue *q, struct request *req, 156 struct bio *bio); 157 int attempt_back_merge(struct request_queue *q, struct request *rq); 158 int attempt_front_merge(struct request_queue *q, struct request *rq); 159 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 160 struct request *next); 161 void blk_recalc_rq_segments(struct request *rq); 162 void blk_rq_set_mixed_merge(struct request *rq); 163 bool blk_rq_merge_ok(struct request *rq, struct bio *bio); 164 int blk_try_merge(struct request *rq, struct bio *bio); 165 166 void blk_queue_congestion_threshold(struct request_queue *q); 167 168 void __blk_run_queue_uncond(struct request_queue *q); 169 170 int blk_dev_init(void); 171 172 173 /* 174 * Return the threshold (number of used requests) at which the queue is 175 * considered to be congested. It include a little hysteresis to keep the 176 * context switch rate down. 177 */ 178 static inline int queue_congestion_on_threshold(struct request_queue *q) 179 { 180 return q->nr_congestion_on; 181 } 182 183 /* 184 * The threshold at which a queue is considered to be uncongested 185 */ 186 static inline int queue_congestion_off_threshold(struct request_queue *q) 187 { 188 return q->nr_congestion_off; 189 } 190 191 extern int blk_update_nr_requests(struct request_queue *, unsigned int); 192 193 /* 194 * Contribute to IO statistics IFF: 195 * 196 * a) it's attached to a gendisk, and 197 * b) the queue had IO stats enabled when this request was started, and 198 * c) it's a file system request 199 */ 200 static inline int blk_do_io_stat(struct request *rq) 201 { 202 return rq->rq_disk && 203 (rq->cmd_flags & REQ_IO_STAT) && 204 (rq->cmd_type == REQ_TYPE_FS); 205 } 206 207 /* 208 * Internal io_context interface 209 */ 210 void get_io_context(struct io_context *ioc); 211 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q); 212 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q, 213 gfp_t gfp_mask); 214 void ioc_clear_queue(struct request_queue *q); 215 216 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node); 217 218 /** 219 * create_io_context - try to create task->io_context 220 * @gfp_mask: allocation mask 221 * @node: allocation node 222 * 223 * If %current->io_context is %NULL, allocate a new io_context and install 224 * it. Returns the current %current->io_context which may be %NULL if 225 * allocation failed. 226 * 227 * Note that this function can't be called with IRQ disabled because 228 * task_lock which protects %current->io_context is IRQ-unsafe. 229 */ 230 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node) 231 { 232 WARN_ON_ONCE(irqs_disabled()); 233 if (unlikely(!current->io_context)) 234 create_task_io_context(current, gfp_mask, node); 235 return current->io_context; 236 } 237 238 /* 239 * Internal throttling interface 240 */ 241 #ifdef CONFIG_BLK_DEV_THROTTLING 242 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio); 243 extern void blk_throtl_drain(struct request_queue *q); 244 extern int blk_throtl_init(struct request_queue *q); 245 extern void blk_throtl_exit(struct request_queue *q); 246 #else /* CONFIG_BLK_DEV_THROTTLING */ 247 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio) 248 { 249 return false; 250 } 251 static inline void blk_throtl_drain(struct request_queue *q) { } 252 static inline int blk_throtl_init(struct request_queue *q) { return 0; } 253 static inline void blk_throtl_exit(struct request_queue *q) { } 254 #endif /* CONFIG_BLK_DEV_THROTTLING */ 255 256 #endif /* BLK_INTERNAL_H */ 257