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         struct blk_mq_hw_ctx *hctx;
  43
  44         if (!q->mq_ops)
  45                 return q->fq;
  46
  47         hctx = q->mq_ops->map_queue(q, ctx->cpu);
  48
  49         return hctx->fq;
  50 }
  51
  52 static inline void __blk_get_queue(struct request_queue *q)
  53 {
  54         kobject_get(&q->kobj);
  55 }
  56
  57 struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
  58                 int node, int cmd_size);
  59 void blk_free_flush_queue(struct blk_flush_queue *q);
  60
  61 int blk_init_rl(struct request_list *rl, struct request_queue *q,
  62                 gfp_t gfp_mask);
  63 void blk_exit_rl(struct request_list *rl);
  64 void init_request_from_bio(struct request *req, struct bio *bio);
  65 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
  66                         struct bio *bio);
  67 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
  68                       struct bio *bio);
  69 void blk_queue_bypass_start(struct request_queue *q);
  70 void blk_queue_bypass_end(struct request_queue *q);
  71 void blk_dequeue_request(struct request *rq);
  72 void __blk_queue_free_tags(struct request_queue *q);
  73 bool __blk_end_bidi_request(struct request *rq, int error,
  74                             unsigned int nr_bytes, unsigned int bidi_bytes);
  75
  76 void blk_rq_timed_out_timer(unsigned long data);
  77 unsigned long blk_rq_timeout(unsigned long timeout);
  78 void blk_add_timer(struct request *req);
  79 void blk_delete_timer(struct request *);
  80
  81
  82 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
  83                              struct bio *bio);
  84 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
  85                             struct bio *bio);
  86 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
  87                             unsigned int *request_count,
  88                             struct request **same_queue_rq);
  89
  90 void blk_account_io_start(struct request *req, bool new_io);
  91 void blk_account_io_completion(struct request *req, unsigned int bytes);
  92 void blk_account_io_done(struct request *req);
  93
  94 /*
  95  * Internal atomic flags for request handling
  96  */
  97 enum rq_atomic_flags {
  98         REQ_ATOM_COMPLETE = 0,
  99         REQ_ATOM_STARTED,
 100 };
 101
 102 /*
 103  * EH timer and IO completion will both attempt to 'grab' the request, make
 104  * sure that only one of them succeeds
 105  */
 106 static inline int blk_mark_rq_complete(struct request *rq)
 107 {
 108         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 109 }
 110
 111 static inline void blk_clear_rq_complete(struct request *rq)
 112 {
 113         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 114 }
 115
 116 /*
 117  * Internal elevator interface
 118  */
 119 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
 120
 121 void blk_insert_flush(struct request *rq);
 122
 123 static inline struct request *__elv_next_request(struct request_queue *q)
 124 {
 125         struct request *rq;
 126         struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
 127
 128         while (1) {
 129                 if (!list_empty(&q->queue_head)) {
 130                         rq = list_entry_rq(q->queue_head.next);
 131                         return rq;
 132                 }
 133
 134                 /*
 135                  * Flush request is running and flush request isn't queueable
 136                  * in the drive, we can hold the queue till flush request is
 137                  * finished. Even we don't do this, driver can't dispatch next
 138                  * requests and will requeue them. And this can improve
 139                  * throughput too. For example, we have request flush1, write1,
 140                  * flush 2. flush1 is dispatched, then queue is hold, write1
 141                  * isn't inserted to queue. After flush1 is finished, flush2
 142                  * will be dispatched. Since disk cache is already clean,
 143                  * flush2 will be finished very soon, so looks like flush2 is
 144                  * folded to flush1.
 145                  * Since the queue is hold, a flag is set to indicate the queue
 146                  * should be restarted later. Please see flush_end_io() for
 147                  * details.
 148                  */
 149                 if (fq->flush_pending_idx != fq->flush_running_idx &&
 150                                 !queue_flush_queueable(q)) {
 151                         fq->flush_queue_delayed = 1;
 152                         return NULL;
 153                 }
 154                 if (unlikely(blk_queue_bypass(q)) ||
 155                     !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
 156                         return NULL;
 157         }
 158 }
 159
 160 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 161 {
 162         struct elevator_queue *e = q->elevator;
 163
 164         if (e->type->ops.elevator_activate_req_fn)
 165                 e->type->ops.elevator_activate_req_fn(q, rq);
 166 }
 167
 168 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 169 {
 170         struct elevator_queue *e = q->elevator;
 171
 172         if (e->type->ops.elevator_deactivate_req_fn)
 173                 e->type->ops.elevator_deactivate_req_fn(q, rq);
 174 }
 175
 176 #ifdef CONFIG_FAIL_IO_TIMEOUT
 177 int blk_should_fake_timeout(struct request_queue *);
 178 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 179 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 180                                 const char *, size_t);
 181 #else
 182 static inline int blk_should_fake_timeout(struct request_queue *q)
 183 {
 184         return 0;
 185 }
 186 #endif
 187
 188 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 189                      struct bio *bio);
 190 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 191                       struct bio *bio);
 192 int attempt_back_merge(struct request_queue *q, struct request *rq);
 193 int attempt_front_merge(struct request_queue *q, struct request *rq);
 194 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 195                                 struct request *next);
 196 void blk_recalc_rq_segments(struct request *rq);
 197 void blk_rq_set_mixed_merge(struct request *rq);
 198 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 199 int blk_try_merge(struct request *rq, struct bio *bio);
 200
 201 void blk_queue_congestion_threshold(struct request_queue *q);
 202
 203 int blk_dev_init(void);
 204
 205
 206 /*
 207  * Return the threshold (number of used requests) at which the queue is
 208  * considered to be congested.  It include a little hysteresis to keep the
 209  * context switch rate down.
 210  */
 211 static inline int queue_congestion_on_threshold(struct request_queue *q)
 212 {
 213         return q->nr_congestion_on;
 214 }
 215
 216 /*
 217  * The threshold at which a queue is considered to be uncongested
 218  */
 219 static inline int queue_congestion_off_threshold(struct request_queue *q)
 220 {
 221         return q->nr_congestion_off;
 222 }
 223
 224 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 225
 226 /*
 227  * Contribute to IO statistics IFF:
 228  *
 229  *      a) it's attached to a gendisk, and
 230  *      b) the queue had IO stats enabled when this request was started, and
 231  *      c) it's a file system request
 232  */
 233 static inline int blk_do_io_stat(struct request *rq)
 234 {
 235         return rq->rq_disk &&
 236                (rq->cmd_flags & REQ_IO_STAT) &&
 237                 (rq->cmd_type == REQ_TYPE_FS);
 238 }
 239
 240 /*
 241  * Internal io_context interface
 242  */
 243 void get_io_context(struct io_context *ioc);
 244 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 245 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 246                              gfp_t gfp_mask);
 247 void ioc_clear_queue(struct request_queue *q);
 248
 249 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 250
 251 /**
 252  * create_io_context - try to create task->io_context
 253  * @gfp_mask: allocation mask
 254  * @node: allocation node
 255  *
 256  * If %current->io_context is %NULL, allocate a new io_context and install
 257  * it.  Returns the current %current->io_context which may be %NULL if
 258  * allocation failed.
 259  *
 260  * Note that this function can't be called with IRQ disabled because
 261  * task_lock which protects %current->io_context is IRQ-unsafe.
 262  */
 263 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 264 {
 265         WARN_ON_ONCE(irqs_disabled());
 266         if (unlikely(!current->io_context))
 267                 create_task_io_context(current, gfp_mask, node);
 268         return current->io_context;
 269 }
 270
 271 /*
 272  * Internal throttling interface
 273  */
 274 #ifdef CONFIG_BLK_DEV_THROTTLING
 275 extern void blk_throtl_drain(struct request_queue *q);
 276 extern int blk_throtl_init(struct request_queue *q);
 277 extern void blk_throtl_exit(struct request_queue *q);
 278 #else /* CONFIG_BLK_DEV_THROTTLING */
 279 static inline void blk_throtl_drain(struct request_queue *q) { }
 280 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 281 static inline void blk_throtl_exit(struct request_queue *q) { }
 282 #endif /* CONFIG_BLK_DEV_THROTTLING */
 283
 284 #endif /* BLK_INTERNAL_H */