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 int blk_queue_enter(struct request_queue *q, gfp_t gfp);
  76 void blk_queue_exit(struct request_queue *q);
  77 void blk_freeze_queue(struct request_queue *q);
  78
  79 static inline void blk_queue_enter_live(struct request_queue *q)
  80 {
  81         /*
  82          * Given that running in generic_make_request() context
  83          * guarantees that a live reference against q_usage_counter has
  84          * been established, further references under that same context
  85          * need not check that the queue has been frozen (marked dead).
  86          */
  87         percpu_ref_get(&q->q_usage_counter);
  88 }
  89
  90 #ifdef CONFIG_BLK_DEV_INTEGRITY
  91 void blk_flush_integrity(void);
  92 #else
  93 static inline void blk_flush_integrity(void)
  94 {
  95 }
  96 #endif
  97
  98 void blk_rq_timed_out_timer(unsigned long data);
  99 unsigned long blk_rq_timeout(unsigned long timeout);
 100 void blk_add_timer(struct request *req);
 101 void blk_delete_timer(struct request *);
 102
 103
 104 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
 105                              struct bio *bio);
 106 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
 107                             struct bio *bio);
 108 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
 109                             unsigned int *request_count,
 110                             struct request **same_queue_rq);
 111 unsigned int blk_plug_queued_count(struct request_queue *q);
 112
 113 void blk_account_io_start(struct request *req, bool new_io);
 114 void blk_account_io_completion(struct request *req, unsigned int bytes);
 115 void blk_account_io_done(struct request *req);
 116
 117 /*
 118  * Internal atomic flags for request handling
 119  */
 120 enum rq_atomic_flags {
 121         REQ_ATOM_COMPLETE = 0,
 122         REQ_ATOM_STARTED,
 123 };
 124
 125 /*
 126  * EH timer and IO completion will both attempt to 'grab' the request, make
 127  * sure that only one of them succeeds
 128  */
 129 static inline int blk_mark_rq_complete(struct request *rq)
 130 {
 131         return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 132 }
 133
 134 static inline void blk_clear_rq_complete(struct request *rq)
 135 {
 136         clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 137 }
 138
 139 /*
 140  * Internal elevator interface
 141  */
 142 #define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
 143
 144 void blk_insert_flush(struct request *rq);
 145
 146 static inline struct request *__elv_next_request(struct request_queue *q)
 147 {
 148         struct request *rq;
 149         struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
 150
 151         while (1) {
 152                 if (!list_empty(&q->queue_head)) {
 153                         rq = list_entry_rq(q->queue_head.next);
 154                         return rq;
 155                 }
 156
 157                 /*
 158                  * Flush request is running and flush request isn't queueable
 159                  * in the drive, we can hold the queue till flush request is
 160                  * finished. Even we don't do this, driver can't dispatch next
 161                  * requests and will requeue them. And this can improve
 162                  * throughput too. For example, we have request flush1, write1,
 163                  * flush 2. flush1 is dispatched, then queue is hold, write1
 164                  * isn't inserted to queue. After flush1 is finished, flush2
 165                  * will be dispatched. Since disk cache is already clean,
 166                  * flush2 will be finished very soon, so looks like flush2 is
 167                  * folded to flush1.
 168                  * Since the queue is hold, a flag is set to indicate the queue
 169                  * should be restarted later. Please see flush_end_io() for
 170                  * details.
 171                  */
 172                 if (fq->flush_pending_idx != fq->flush_running_idx &&
 173                                 !queue_flush_queueable(q)) {
 174                         fq->flush_queue_delayed = 1;
 175                         return NULL;
 176                 }
 177                 if (unlikely(blk_queue_bypass(q)) ||
 178                     !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
 179                         return NULL;
 180         }
 181 }
 182
 183 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
 184 {
 185         struct elevator_queue *e = q->elevator;
 186
 187         if (e->type->ops.elevator_activate_req_fn)
 188                 e->type->ops.elevator_activate_req_fn(q, rq);
 189 }
 190
 191 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
 192 {
 193         struct elevator_queue *e = q->elevator;
 194
 195         if (e->type->ops.elevator_deactivate_req_fn)
 196                 e->type->ops.elevator_deactivate_req_fn(q, rq);
 197 }
 198
 199 #ifdef CONFIG_FAIL_IO_TIMEOUT
 200 int blk_should_fake_timeout(struct request_queue *);
 201 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
 202 ssize_t part_timeout_store(struct device *, struct device_attribute *,
 203                                 const char *, size_t);
 204 #else
 205 static inline int blk_should_fake_timeout(struct request_queue *q)
 206 {
 207         return 0;
 208 }
 209 #endif
 210
 211 int ll_back_merge_fn(struct request_queue *q, struct request *req,
 212                      struct bio *bio);
 213 int ll_front_merge_fn(struct request_queue *q, struct request *req,
 214                       struct bio *bio);
 215 int attempt_back_merge(struct request_queue *q, struct request *rq);
 216 int attempt_front_merge(struct request_queue *q, struct request *rq);
 217 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 218                                 struct request *next);
 219 void blk_recalc_rq_segments(struct request *rq);
 220 void blk_rq_set_mixed_merge(struct request *rq);
 221 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 222 int blk_try_merge(struct request *rq, struct bio *bio);
 223
 224 void blk_queue_congestion_threshold(struct request_queue *q);
 225
 226 int blk_dev_init(void);
 227
 228
 229 /*
 230  * Return the threshold (number of used requests) at which the queue is
 231  * considered to be congested.  It include a little hysteresis to keep the
 232  * context switch rate down.
 233  */
 234 static inline int queue_congestion_on_threshold(struct request_queue *q)
 235 {
 236         return q->nr_congestion_on;
 237 }
 238
 239 /*
 240  * The threshold at which a queue is considered to be uncongested
 241  */
 242 static inline int queue_congestion_off_threshold(struct request_queue *q)
 243 {
 244         return q->nr_congestion_off;
 245 }
 246
 247 extern int blk_update_nr_requests(struct request_queue *, unsigned int);
 248
 249 /*
 250  * Contribute to IO statistics IFF:
 251  *
 252  *      a) it's attached to a gendisk, and
 253  *      b) the queue had IO stats enabled when this request was started, and
 254  *      c) it's a file system request
 255  */
 256 static inline int blk_do_io_stat(struct request *rq)
 257 {
 258         return rq->rq_disk &&
 259                (rq->cmd_flags & REQ_IO_STAT) &&
 260                 (rq->cmd_type == REQ_TYPE_FS);
 261 }
 262
 263 /*
 264  * Internal io_context interface
 265  */
 266 void get_io_context(struct io_context *ioc);
 267 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
 268 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
 269                              gfp_t gfp_mask);
 270 void ioc_clear_queue(struct request_queue *q);
 271
 272 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
 273
 274 /**
 275  * create_io_context - try to create task->io_context
 276  * @gfp_mask: allocation mask
 277  * @node: allocation node
 278  *
 279  * If %current->io_context is %NULL, allocate a new io_context and install
 280  * it.  Returns the current %current->io_context which may be %NULL if
 281  * allocation failed.
 282  *
 283  * Note that this function can't be called with IRQ disabled because
 284  * task_lock which protects %current->io_context is IRQ-unsafe.
 285  */
 286 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
 287 {
 288         WARN_ON_ONCE(irqs_disabled());
 289         if (unlikely(!current->io_context))
 290                 create_task_io_context(current, gfp_mask, node);
 291         return current->io_context;
 292 }
 293
 294 /*
 295  * Internal throttling interface
 296  */
 297 #ifdef CONFIG_BLK_DEV_THROTTLING
 298 extern void blk_throtl_drain(struct request_queue *q);
 299 extern int blk_throtl_init(struct request_queue *q);
 300 extern void blk_throtl_exit(struct request_queue *q);
 301 #else /* CONFIG_BLK_DEV_THROTTLING */
 302 static inline void blk_throtl_drain(struct request_queue *q) { }
 303 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
 304 static inline void blk_throtl_exit(struct request_queue *q) { }
 305 #endif /* CONFIG_BLK_DEV_THROTTLING */
 306
 307 #endif /* BLK_INTERNAL_H */