wait: use EXIT_TRACE only if thread_group_leader(zombie)
[linux/fpc-iii.git] / block / blk.h
blobd23b415b8a28f90e0ff83c713e0c2677a1e00f96
1 #ifndef BLK_INTERNAL_H
2 #define BLK_INTERNAL_H
4 #include <linux/idr.h>
6 /* Amount of time in which a process may batch requests */
7 #define BLK_BATCH_TIME (HZ/50UL)
9 /* Number of requests a "batching" process may submit */
10 #define BLK_BATCH_REQ 32
12 extern struct kmem_cache *blk_requestq_cachep;
13 extern struct kmem_cache *request_cachep;
14 extern struct kobj_type blk_queue_ktype;
15 extern struct ida blk_queue_ida;
17 static inline void __blk_get_queue(struct request_queue *q)
19 kobject_get(&q->kobj);
22 int blk_init_rl(struct request_list *rl, struct request_queue *q,
23 gfp_t gfp_mask);
24 void blk_exit_rl(struct request_list *rl);
25 void init_request_from_bio(struct request *req, struct bio *bio);
26 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
27 struct bio *bio);
28 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
29 struct bio *bio);
30 void blk_queue_bypass_start(struct request_queue *q);
31 void blk_queue_bypass_end(struct request_queue *q);
32 void blk_dequeue_request(struct request *rq);
33 void __blk_queue_free_tags(struct request_queue *q);
34 bool __blk_end_bidi_request(struct request *rq, int error,
35 unsigned int nr_bytes, unsigned int bidi_bytes);
37 void blk_rq_timed_out_timer(unsigned long data);
38 void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout,
39 unsigned int *next_set);
40 void __blk_add_timer(struct request *req, struct list_head *timeout_list);
41 void blk_delete_timer(struct request *);
42 void blk_add_timer(struct request *);
45 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
46 struct bio *bio);
47 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
48 struct bio *bio);
49 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
50 unsigned int *request_count);
52 void blk_account_io_start(struct request *req, bool new_io);
53 void blk_account_io_completion(struct request *req, unsigned int bytes);
54 void blk_account_io_done(struct request *req);
57 * Internal atomic flags for request handling
59 enum rq_atomic_flags {
60 REQ_ATOM_COMPLETE = 0,
61 REQ_ATOM_STARTED,
65 * EH timer and IO completion will both attempt to 'grab' the request, make
66 * sure that only one of them succeeds
68 static inline int blk_mark_rq_complete(struct request *rq)
70 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
73 static inline void blk_clear_rq_complete(struct request *rq)
75 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
79 * Internal elevator interface
81 #define ELV_ON_HASH(rq) hash_hashed(&(rq)->hash)
83 void blk_insert_flush(struct request *rq);
84 void blk_abort_flushes(struct request_queue *q);
86 static inline struct request *__elv_next_request(struct request_queue *q)
88 struct request *rq;
90 while (1) {
91 if (!list_empty(&q->queue_head)) {
92 rq = list_entry_rq(q->queue_head.next);
93 return rq;
97 * Flush request is running and flush request isn't queueable
98 * in the drive, we can hold the queue till flush request is
99 * finished. Even we don't do this, driver can't dispatch next
100 * requests and will requeue them. And this can improve
101 * throughput too. For example, we have request flush1, write1,
102 * flush 2. flush1 is dispatched, then queue is hold, write1
103 * isn't inserted to queue. After flush1 is finished, flush2
104 * will be dispatched. Since disk cache is already clean,
105 * flush2 will be finished very soon, so looks like flush2 is
106 * folded to flush1.
107 * Since the queue is hold, a flag is set to indicate the queue
108 * should be restarted later. Please see flush_end_io() for
109 * details.
111 if (q->flush_pending_idx != q->flush_running_idx &&
112 !queue_flush_queueable(q)) {
113 q->flush_queue_delayed = 1;
114 return NULL;
116 if (unlikely(blk_queue_bypass(q)) ||
117 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
118 return NULL;
122 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
124 struct elevator_queue *e = q->elevator;
126 if (e->type->ops.elevator_activate_req_fn)
127 e->type->ops.elevator_activate_req_fn(q, rq);
130 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
132 struct elevator_queue *e = q->elevator;
134 if (e->type->ops.elevator_deactivate_req_fn)
135 e->type->ops.elevator_deactivate_req_fn(q, rq);
138 #ifdef CONFIG_FAIL_IO_TIMEOUT
139 int blk_should_fake_timeout(struct request_queue *);
140 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
141 ssize_t part_timeout_store(struct device *, struct device_attribute *,
142 const char *, size_t);
143 #else
144 static inline int blk_should_fake_timeout(struct request_queue *q)
146 return 0;
148 #endif
150 int ll_back_merge_fn(struct request_queue *q, struct request *req,
151 struct bio *bio);
152 int ll_front_merge_fn(struct request_queue *q, struct request *req,
153 struct bio *bio);
154 int attempt_back_merge(struct request_queue *q, struct request *rq);
155 int attempt_front_merge(struct request_queue *q, struct request *rq);
156 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
157 struct request *next);
158 void blk_recalc_rq_segments(struct request *rq);
159 void blk_rq_set_mixed_merge(struct request *rq);
160 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
161 int blk_try_merge(struct request *rq, struct bio *bio);
163 void blk_queue_congestion_threshold(struct request_queue *q);
165 void __blk_run_queue_uncond(struct request_queue *q);
167 int blk_dev_init(void);
171 * Return the threshold (number of used requests) at which the queue is
172 * considered to be congested. It include a little hysteresis to keep the
173 * context switch rate down.
175 static inline int queue_congestion_on_threshold(struct request_queue *q)
177 return q->nr_congestion_on;
181 * The threshold at which a queue is considered to be uncongested
183 static inline int queue_congestion_off_threshold(struct request_queue *q)
185 return q->nr_congestion_off;
189 * Contribute to IO statistics IFF:
191 * a) it's attached to a gendisk, and
192 * b) the queue had IO stats enabled when this request was started, and
193 * c) it's a file system request
195 static inline int blk_do_io_stat(struct request *rq)
197 return rq->rq_disk &&
198 (rq->cmd_flags & REQ_IO_STAT) &&
199 (rq->cmd_type == REQ_TYPE_FS);
203 * Internal io_context interface
205 void get_io_context(struct io_context *ioc);
206 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
207 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
208 gfp_t gfp_mask);
209 void ioc_clear_queue(struct request_queue *q);
211 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
214 * create_io_context - try to create task->io_context
215 * @gfp_mask: allocation mask
216 * @node: allocation node
218 * If %current->io_context is %NULL, allocate a new io_context and install
219 * it. Returns the current %current->io_context which may be %NULL if
220 * allocation failed.
222 * Note that this function can't be called with IRQ disabled because
223 * task_lock which protects %current->io_context is IRQ-unsafe.
225 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
227 WARN_ON_ONCE(irqs_disabled());
228 if (unlikely(!current->io_context))
229 create_task_io_context(current, gfp_mask, node);
230 return current->io_context;
234 * Internal throttling interface
236 #ifdef CONFIG_BLK_DEV_THROTTLING
237 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
238 extern void blk_throtl_drain(struct request_queue *q);
239 extern int blk_throtl_init(struct request_queue *q);
240 extern void blk_throtl_exit(struct request_queue *q);
241 #else /* CONFIG_BLK_DEV_THROTTLING */
242 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
244 return false;
246 static inline void blk_throtl_drain(struct request_queue *q) { }
247 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
248 static inline void blk_throtl_exit(struct request_queue *q) { }
249 #endif /* CONFIG_BLK_DEV_THROTTLING */
251 #endif /* BLK_INTERNAL_H */