block/blk.h

   1 #ifndef BLK_INTERNAL_H
   2 #define BLK_INTERNAL_H
   3
   4 #include <linux/idr.h>
   5 #include <linux/blk-mq.h>
   6 #include "blk-mq.h"
   7
   8 /* Amount of time in which a process may batch requests */
   9 #define BLK_BATCH_TIME  (HZ/50UL)
  10
  11 /* Number of requests a "batching" process may submit */
  12 #define BLK_BATCH_REQ   32
  13
  14 /* Max future timer expiry for timeouts */
  15 #define BLK_MAX_TIMEOUT         (5 * HZ)
  16
  17 struct blk_flush_queue {
  18         unsigned int            flush_queue_delayed:1;
  19         unsigned int            flush_pending_idx:1;
  20         unsigned int            flush_running_idx:1;
  21         unsigned long           flush_pending_since;
  22         struct list_head        flush_queue[2];
  23         struct list_head        flush_data_in_flight;
  24         struct request          *flush_rq;
  25
  26         /*
  27          * flush_rq shares tag with this rq, both can't be active
  28          * at the same time
  29          */
  30         struct request          *orig_rq;
  31         spinlock_t              mq_flush_lock;
  32 };
  33
  34 extern struct kmem_cache *blk_requestq_cachep;
  35 extern struct kmem_cache *request_cachep;
  36 extern struct kobj_type blk_queue_ktype;
  37 extern struct ida blk_queue_ida;
  38
  39 static inline struct blk_flush_queue *blk_get_flush_queue(
  40                 struct request_queue *q, struct blk_mq_ctx *ctx)
  41 {
  42         if (q->mq_ops)
  43                 return blk_mq_map_queue(q, ctx->cpu)->fq;
  44         return q->fq;
  45 }
  46
  47 static inline void __blk_get_queue(struct request_queue *q)
  48 {
  49         kobject_get(&q->kobj);
  50 }
  51
  52 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
  53                 int node, int cmd_size);
  54 void blk_free_flush_queue(struct blk_flush_queue *q);
  55
  56 int blk_init_rl(struct request_list *rl, struct request_queue *q,
  57                 gfp_t gfp_mask);
  58 void blk_exit_rl(struct request_list *rl);
  59 void init_request_from_bio(struct request *req, struct bio *bio);
  60 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  61                         struct bio *bio);
  62 void blk_queue_bypass_start(struct request_queue *q);
  63 void blk_queue_bypass_end(struct request_queue *q);
  64 void blk_dequeue_request(struct request *rq);
  65 void __blk_queue_free_tags(struct request_queue *q);
  66 bool __blk_end_bidi_request(struct request *rq, int error,
  67                             unsigned int nr_bytes, unsigned int bidi_bytes);
  68 void blk_freeze_queue(struct request_queue *q);
  69
  70 static inline void blk_queue_enter_live(struct request_queue *q)
  71 {
  72         /*
  73          * Given that running in generic_make_request() context
  74          * guarantees that a live reference against q_usage_counter has
  75          * been established, further references under that same context
  76          * need not check that the queue has been frozen (marked dead).
  77          */
  78         percpu_ref_get(&q->q_usage_counter);
  79 }
  80
  81 #ifdef CONFIG_BLK_DEV_INTEGRITY
  82 void blk_flush_integrity(void);
  83 #else
  84 static inline void blk_flush_integrity(void)
  85 {
  86 }
  87 #endif
  88
  89 void blk_timeout_work(struct work_struct *work);
  90 unsigned long blk_rq_timeout(unsigned long timeout);
  91 void blk_add_timer(struct request *req);
  92 void blk_delete_timer(struct request *);
  93
  94
  95 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
  96                              struct bio *bio);
  97 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
  98                             struct bio *bio);
  99 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 100                             unsigned int *request_count,
 101                             struct request **same_queue_rq);
 102 unsigned int blk_plug_queued_count(struct request_queue *q);
 103
 104 void blk_account_io_start(struct request *req, bool new_io);
 105 void blk_account_io_completion(struct request *req, unsigned int bytes);
 106 void blk_account_io_done(struct request *req);
 107
 108 /*
 109  * Internal atomic flags for request handling
 110  */
 111 enum rq_atomic_flags {
 112         REQ_ATOM_COMPLETE = 0,
 113         REQ_ATOM_STARTED,
 114         REQ_ATOM_POLL_SLEPT,
 115 };
 116
 117 /*
 118  * EH timer and IO completion will both attempt to 'grab' the request, make
 119  * sure that only one of them succeeds
 120  */
 121 static inline int blk_mark_rq_complete(struct request *rq)
 122 {
 123         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 124 }
 125
 126 static inline void blk_clear_rq_complete(struct request *rq)
 127 {
 128         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 129 }
 130
 131 /*
 132  * Internal elevator interface
 133  */
 134 #define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
 135
 136 void blk_insert_flush(struct request *rq);
 137
 138 static inline struct request *__elv_next_request(struct request_queue *q)
 139 {
 140         struct request *rq;
 141         struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
 142
 143         while (1) {
 144                 if (!list_empty(&q->queue_head)) {
 145                         rq = list_entry_rq(q->queue_head.next);
 146                         return rq;
 147                 }
 148
 149                 /*
 150                  * Flush request is running and flush request isn't queueable
 151                  * in the drive, we can hold the queue till flush request is
 152                  * finished. Even we don't do this, driver can't dispatch next
 153                  * requests and will requeue them. And this can improve
 154                  * throughput too. For example, we have request flush1, write1,
 155                  * flush 2. flush1 is dispatched, then queue is hold, write1
 156                  * isn't inserted to queue. After flush1 is finished, flush2
 157                  * will be dispatched. Since disk cache is already clean,
 158                  * flush2 will be finished very soon, so looks like flush2 is
 159                  * folded to flush1.
 160                  * Since the queue is hold, a flag is set to indicate the queue
 161                  * should be restarted later. Please see flush_end_io() for
 162                  * details.
 163                  */
 164                 if (fq->flush_pending_idx != fq->flush_running_idx &&
 165                                 !queue_flush_queueable(q)) {
 166                         fq->flush_queue_delayed = 1;
 167                         return NULL;
 168                 }
 169                 if (unlikely(blk_queue_bypass(q)) ||
 170                     !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
 171                         return NULL;
 172         }
 173 }
 174
 175 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 176 {
 177         struct elevator_queue *e = q->elevator;
 178
 179         if (e->type->ops.elevator_activate_req_fn)
 180                 e->type->ops.elevator_activate_req_fn(q, rq);
 181 }
 182
 183 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 184 {
 185         struct elevator_queue *e = q->elevator;
 186
 187         if (e->type->ops.elevator_deactivate_req_fn)
 188                 e->type->ops.elevator_deactivate_req_fn(q, rq);
 189 }
 190
 191 #ifdef CONFIG_FAIL_IO_TIMEOUT
 192 int blk_should_fake_timeout(struct request_queue *);
 193 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 194 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 195                                 const char *, size_t);
 196 #else
 197 static inline int blk_should_fake_timeout(struct request_queue *q)
 198 {
 199         return 0;
 200 }
 201 #endif
 202
 203 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 204                      struct bio *bio);
 205 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 206                       struct bio *bio);
 207 int attempt_back_merge(struct request_queue *q, struct request *rq);
 208 int attempt_front_merge(struct request_queue *q, struct request *rq);
 209 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 210                                 struct request *next);
 211 void blk_recalc_rq_segments(struct request *rq);
 212 void blk_rq_set_mixed_merge(struct request *rq);
 213 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 214 int blk_try_merge(struct request *rq, struct bio *bio);
 215
 216 void blk_queue_congestion_threshold(struct request_queue *q);
 217
 218 int blk_dev_init(void);
 219
 220
 221 /*
 222  * Return the threshold (number of used requests) at which the queue is
 223  * considered to be congested.  It include a little hysteresis to keep the
 224  * context switch rate down.
 225  */
 226 static inline int queue_congestion_on_threshold(struct request_queue *q)
 227 {
 228         return q->nr_congestion_on;
 229 }
 230
 231 /*
 232  * The threshold at which a queue is considered to be uncongested
 233  */
 234 static inline int queue_congestion_off_threshold(struct request_queue *q)
 235 {
 236         return q->nr_congestion_off;
 237 }
 238
 239 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 240
 241 /*
 242  * Contribute to IO statistics IFF:
 243  *
 244  *      a) it's attached to a gendisk, and
 245  *      b) the queue had IO stats enabled when this request was started, and
 246  *      c) it's a file system request
 247  */
 248 static inline int blk_do_io_stat(struct request *rq)
 249 {
 250         return rq->rq_disk &&
 251                (rq->rq_flags & RQF_IO_STAT) &&
 252                 (rq->cmd_type == REQ_TYPE_FS);
 253 }
 254
 255 /*
 256  * Internal io_context interface
 257  */
 258 void get_io_context(struct io_context *ioc);
 259 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 260 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 261                              gfp_t gfp_mask);
 262 void ioc_clear_queue(struct request_queue *q);
 263
 264 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 265
 266 /**
 267  * create_io_context - try to create task->io_context
 268  * @gfp_mask: allocation mask
 269  * @node: allocation node
 270  *
 271  * If %current->io_context is %NULL, allocate a new io_context and install
 272  * it.  Returns the current %current->io_context which may be %NULL if
 273  * allocation failed.
 274  *
 275  * Note that this function can't be called with IRQ disabled because
 276  * task_lock which protects %current->io_context is IRQ-unsafe.
 277  */
 278 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 279 {
 280         WARN_ON_ONCE(irqs_disabled());
 281         if (unlikely(!current->io_context))
 282                 create_task_io_context(current, gfp_mask, node);
 283         return current->io_context;
 284 }
 285
 286 /*
 287  * Internal throttling interface
 288  */
 289 #ifdef CONFIG_BLK_DEV_THROTTLING
 290 extern void blk_throtl_drain(struct request_queue *q);
 291 extern int blk_throtl_init(struct request_queue *q);
 292 extern void blk_throtl_exit(struct request_queue *q);
 293 #else /* CONFIG_BLK_DEV_THROTTLING */
 294 static inline void blk_throtl_drain(struct request_queue *q) { }
 295 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 296 static inline void blk_throtl_exit(struct request_queue *q) { }
 297 #endif /* CONFIG_BLK_DEV_THROTTLING */
 298
 299 #endif /* BLK_INTERNAL_H */