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1#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H
3
4/* Amount of time in which a process may batch requests */
5#define BLK_BATCH_TIME (HZ/50UL)
6
7/* Number of requests a "batching" process may submit */
8#define BLK_BATCH_REQ 32
9
10extern struct kmem_cache *blk_requestq_cachep;
11extern struct kobj_type blk_queue_ktype;
12
13void init_request_from_bio(struct request *req, struct bio *bio);
14void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
15 struct bio *bio);
16int blk_rq_append_bio(struct request_queue *q, struct request *rq,
17 struct bio *bio);
18void blk_dequeue_request(struct request *rq);
19void __blk_queue_free_tags(struct request_queue *q);
20bool __blk_end_bidi_request(struct request *rq, int error,
21 unsigned int nr_bytes, unsigned int bidi_bytes);
22
23void blk_rq_timed_out_timer(unsigned long data);
24void blk_delete_timer(struct request *);
25void blk_add_timer(struct request *);
26void __generic_unplug_device(struct request_queue *);
27
28/*
29 * Internal atomic flags for request handling
30 */
31enum rq_atomic_flags {
32 REQ_ATOM_COMPLETE = 0,
33};
34
35/*
36 * EH timer and IO completion will both attempt to 'grab' the request, make
37 * sure that only one of them succeeds
38 */
39static inline int blk_mark_rq_complete(struct request *rq)
40{
41 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
42}
43
44static inline void blk_clear_rq_complete(struct request *rq)
45{
46 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
47}
48
49/*
50 * Internal elevator interface
51 */
52#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
53
54void blk_insert_flush(struct request *rq);
55void blk_abort_flushes(struct request_queue *q);
56
57static inline struct request *__elv_next_request(struct request_queue *q)
58{
59 struct request *rq;
60
61 while (1) {
62 if (!list_empty(&q->queue_head)) {
63 rq = list_entry_rq(q->queue_head.next);
64 return rq;
65 }
66
67 /*
68 * Flush request is running and flush request isn't queueable
69 * in the drive, we can hold the queue till flush request is
70 * finished. Even we don't do this, driver can't dispatch next
71 * requests and will requeue them. And this can improve
72 * throughput too. For example, we have request flush1, write1,
73 * flush 2. flush1 is dispatched, then queue is hold, write1
74 * isn't inserted to queue. After flush1 is finished, flush2
75 * will be dispatched. Since disk cache is already clean,
76 * flush2 will be finished very soon, so looks like flush2 is
77 * folded to flush1.
78 * Since the queue is hold, a flag is set to indicate the queue
79 * should be restarted later. Please see flush_end_io() for
80 * details.
81 */
82 if (q->flush_pending_idx != q->flush_running_idx &&
83 !queue_flush_queueable(q)) {
84 q->flush_queue_delayed = 1;
85 return NULL;
86 }
87 if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
88 !q->elevator->ops->elevator_dispatch_fn(q, 0))
89 return NULL;
90 }
91}
92
93static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
94{
95 struct elevator_queue *e = q->elevator;
96
97 if (e->ops->elevator_activate_req_fn)
98 e->ops->elevator_activate_req_fn(q, rq);
99}
100
101static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
102{
103 struct elevator_queue *e = q->elevator;
104
105 if (e->ops->elevator_deactivate_req_fn)
106 e->ops->elevator_deactivate_req_fn(q, rq);
107}
108
109#ifdef CONFIG_FAIL_IO_TIMEOUT
110int blk_should_fake_timeout(struct request_queue *);
111ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
112ssize_t part_timeout_store(struct device *, struct device_attribute *,
113 const char *, size_t);
114#else
115static inline int blk_should_fake_timeout(struct request_queue *q)
116{
117 return 0;
118}
119#endif
120
121struct io_context *current_io_context(gfp_t gfp_flags, int node);
122
123int ll_back_merge_fn(struct request_queue *q, struct request *req,
124 struct bio *bio);
125int ll_front_merge_fn(struct request_queue *q, struct request *req,
126 struct bio *bio);
127int attempt_back_merge(struct request_queue *q, struct request *rq);
128int attempt_front_merge(struct request_queue *q, struct request *rq);
129int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
130 struct request *next);
131void blk_recalc_rq_segments(struct request *rq);
132void blk_rq_set_mixed_merge(struct request *rq);
133
134void blk_queue_congestion_threshold(struct request_queue *q);
135
136int blk_dev_init(void);
137
138void elv_quiesce_start(struct request_queue *q);
139void elv_quiesce_end(struct request_queue *q);
140
141
142/*
143 * Return the threshold (number of used requests) at which the queue is
144 * considered to be congested. It include a little hysteresis to keep the
145 * context switch rate down.
146 */
147static inline int queue_congestion_on_threshold(struct request_queue *q)
148{
149 return q->nr_congestion_on;
150}
151
152/*
153 * The threshold at which a queue is considered to be uncongested
154 */
155static inline int queue_congestion_off_threshold(struct request_queue *q)
156{
157 return q->nr_congestion_off;
158}
159
160static inline int blk_cpu_to_group(int cpu)
161{
162 int group = NR_CPUS;
163#ifdef CONFIG_SCHED_MC
164 const struct cpumask *mask = cpu_coregroup_mask(cpu);
165 group = cpumask_first(mask);
166#elif defined(CONFIG_SCHED_SMT)
167 group = cpumask_first(topology_thread_cpumask(cpu));
168#else
169 return cpu;
170#endif
171 if (likely(group < NR_CPUS))
172 return group;
173 return cpu;
174}
175
176/*
177 * Contribute to IO statistics IFF:
178 *
179 * a) it's attached to a gendisk, and
180 * b) the queue had IO stats enabled when this request was started, and
181 * c) it's a file system request or a discard request
182 */
183static inline int blk_do_io_stat(struct request *rq)
184{
185 return rq->rq_disk &&
186 (rq->cmd_flags & REQ_IO_STAT) &&
187 (rq->cmd_type == REQ_TYPE_FS ||
188 (rq->cmd_flags & REQ_DISCARD));
189}
190
191#endif
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
17struct 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
34extern struct kmem_cache *blk_requestq_cachep;
35extern struct kmem_cache *request_cachep;
36extern struct kobj_type blk_queue_ktype;
37extern struct ida blk_queue_ida;
38
39static 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
52static inline void __blk_get_queue(struct request_queue *q)
53{
54 kobject_get(&q->kobj);
55}
56
57struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
58 int node, int cmd_size);
59void blk_free_flush_queue(struct blk_flush_queue *q);
60
61int blk_init_rl(struct request_list *rl, struct request_queue *q,
62 gfp_t gfp_mask);
63void blk_exit_rl(struct request_list *rl);
64void init_request_from_bio(struct request *req, struct bio *bio);
65void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
66 struct bio *bio);
67int blk_rq_append_bio(struct request_queue *q, struct request *rq,
68 struct bio *bio);
69void blk_queue_bypass_start(struct request_queue *q);
70void blk_queue_bypass_end(struct request_queue *q);
71void blk_dequeue_request(struct request *rq);
72void __blk_queue_free_tags(struct request_queue *q);
73bool __blk_end_bidi_request(struct request *rq, int error,
74 unsigned int nr_bytes, unsigned int bidi_bytes);
75void blk_freeze_queue(struct request_queue *q);
76
77static inline void blk_queue_enter_live(struct request_queue *q)
78{
79 /*
80 * Given that running in generic_make_request() context
81 * guarantees that a live reference against q_usage_counter has
82 * been established, further references under that same context
83 * need not check that the queue has been frozen (marked dead).
84 */
85 percpu_ref_get(&q->q_usage_counter);
86}
87
88#ifdef CONFIG_BLK_DEV_INTEGRITY
89void blk_flush_integrity(void);
90#else
91static inline void blk_flush_integrity(void)
92{
93}
94#endif
95
96void blk_timeout_work(struct work_struct *work);
97unsigned long blk_rq_timeout(unsigned long timeout);
98void blk_add_timer(struct request *req);
99void blk_delete_timer(struct request *);
100
101
102bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
103 struct bio *bio);
104bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
105 struct bio *bio);
106bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
107 unsigned int *request_count,
108 struct request **same_queue_rq);
109unsigned int blk_plug_queued_count(struct request_queue *q);
110
111void blk_account_io_start(struct request *req, bool new_io);
112void blk_account_io_completion(struct request *req, unsigned int bytes);
113void blk_account_io_done(struct request *req);
114
115/*
116 * Internal atomic flags for request handling
117 */
118enum rq_atomic_flags {
119 REQ_ATOM_COMPLETE = 0,
120 REQ_ATOM_STARTED,
121};
122
123/*
124 * EH timer and IO completion will both attempt to 'grab' the request, make
125 * sure that only one of them succeeds
126 */
127static inline int blk_mark_rq_complete(struct request *rq)
128{
129 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
130}
131
132static inline void blk_clear_rq_complete(struct request *rq)
133{
134 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
135}
136
137/*
138 * Internal elevator interface
139 */
140#define ELV_ON_HASH(rq) ((rq)->cmd_flags & REQ_HASHED)
141
142void blk_insert_flush(struct request *rq);
143
144static inline struct request *__elv_next_request(struct request_queue *q)
145{
146 struct request *rq;
147 struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
148
149 while (1) {
150 if (!list_empty(&q->queue_head)) {
151 rq = list_entry_rq(q->queue_head.next);
152 return rq;
153 }
154
155 /*
156 * Flush request is running and flush request isn't queueable
157 * in the drive, we can hold the queue till flush request is
158 * finished. Even we don't do this, driver can't dispatch next
159 * requests and will requeue them. And this can improve
160 * throughput too. For example, we have request flush1, write1,
161 * flush 2. flush1 is dispatched, then queue is hold, write1
162 * isn't inserted to queue. After flush1 is finished, flush2
163 * will be dispatched. Since disk cache is already clean,
164 * flush2 will be finished very soon, so looks like flush2 is
165 * folded to flush1.
166 * Since the queue is hold, a flag is set to indicate the queue
167 * should be restarted later. Please see flush_end_io() for
168 * details.
169 */
170 if (fq->flush_pending_idx != fq->flush_running_idx &&
171 !queue_flush_queueable(q)) {
172 fq->flush_queue_delayed = 1;
173 return NULL;
174 }
175 if (unlikely(blk_queue_bypass(q)) ||
176 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
177 return NULL;
178 }
179}
180
181static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
182{
183 struct elevator_queue *e = q->elevator;
184
185 if (e->type->ops.elevator_activate_req_fn)
186 e->type->ops.elevator_activate_req_fn(q, rq);
187}
188
189static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
190{
191 struct elevator_queue *e = q->elevator;
192
193 if (e->type->ops.elevator_deactivate_req_fn)
194 e->type->ops.elevator_deactivate_req_fn(q, rq);
195}
196
197#ifdef CONFIG_FAIL_IO_TIMEOUT
198int blk_should_fake_timeout(struct request_queue *);
199ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
200ssize_t part_timeout_store(struct device *, struct device_attribute *,
201 const char *, size_t);
202#else
203static inline int blk_should_fake_timeout(struct request_queue *q)
204{
205 return 0;
206}
207#endif
208
209int ll_back_merge_fn(struct request_queue *q, struct request *req,
210 struct bio *bio);
211int ll_front_merge_fn(struct request_queue *q, struct request *req,
212 struct bio *bio);
213int attempt_back_merge(struct request_queue *q, struct request *rq);
214int attempt_front_merge(struct request_queue *q, struct request *rq);
215int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
216 struct request *next);
217void blk_recalc_rq_segments(struct request *rq);
218void blk_rq_set_mixed_merge(struct request *rq);
219bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
220int blk_try_merge(struct request *rq, struct bio *bio);
221
222void blk_queue_congestion_threshold(struct request_queue *q);
223
224int blk_dev_init(void);
225
226
227/*
228 * Return the threshold (number of used requests) at which the queue is
229 * considered to be congested. It include a little hysteresis to keep the
230 * context switch rate down.
231 */
232static inline int queue_congestion_on_threshold(struct request_queue *q)
233{
234 return q->nr_congestion_on;
235}
236
237/*
238 * The threshold at which a queue is considered to be uncongested
239 */
240static inline int queue_congestion_off_threshold(struct request_queue *q)
241{
242 return q->nr_congestion_off;
243}
244
245extern int blk_update_nr_requests(struct request_queue *, unsigned int);
246
247/*
248 * Contribute to IO statistics IFF:
249 *
250 * a) it's attached to a gendisk, and
251 * b) the queue had IO stats enabled when this request was started, and
252 * c) it's a file system request
253 */
254static inline int blk_do_io_stat(struct request *rq)
255{
256 return rq->rq_disk &&
257 (rq->cmd_flags & REQ_IO_STAT) &&
258 (rq->cmd_type == REQ_TYPE_FS);
259}
260
261/*
262 * Internal io_context interface
263 */
264void get_io_context(struct io_context *ioc);
265struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
266struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
267 gfp_t gfp_mask);
268void ioc_clear_queue(struct request_queue *q);
269
270int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
271
272/**
273 * create_io_context - try to create task->io_context
274 * @gfp_mask: allocation mask
275 * @node: allocation node
276 *
277 * If %current->io_context is %NULL, allocate a new io_context and install
278 * it. Returns the current %current->io_context which may be %NULL if
279 * allocation failed.
280 *
281 * Note that this function can't be called with IRQ disabled because
282 * task_lock which protects %current->io_context is IRQ-unsafe.
283 */
284static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
285{
286 WARN_ON_ONCE(irqs_disabled());
287 if (unlikely(!current->io_context))
288 create_task_io_context(current, gfp_mask, node);
289 return current->io_context;
290}
291
292/*
293 * Internal throttling interface
294 */
295#ifdef CONFIG_BLK_DEV_THROTTLING
296extern void blk_throtl_drain(struct request_queue *q);
297extern int blk_throtl_init(struct request_queue *q);
298extern void blk_throtl_exit(struct request_queue *q);
299#else /* CONFIG_BLK_DEV_THROTTLING */
300static inline void blk_throtl_drain(struct request_queue *q) { }
301static inline int blk_throtl_init(struct request_queue *q) { return 0; }
302static inline void blk_throtl_exit(struct request_queue *q) { }
303#endif /* CONFIG_BLK_DEV_THROTTLING */
304
305#endif /* BLK_INTERNAL_H */