xircom_cb: fix device probe error path.
[linux-2.6.git] / block / blk.h
blobd45be871329ec67121d2fd41a53289a593f72eb7
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 kobj_type blk_queue_ktype;
14 extern struct ida blk_queue_ida;
16 static inline void __blk_get_queue(struct request_queue *q)
18 kobject_get(&q->kobj);
21 void init_request_from_bio(struct request *req, struct bio *bio);
22 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
23 struct bio *bio);
24 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
25 struct bio *bio);
26 void blk_drain_queue(struct request_queue *q, bool drain_all);
27 void blk_dequeue_request(struct request *rq);
28 void __blk_queue_free_tags(struct request_queue *q);
29 bool __blk_end_bidi_request(struct request *rq, int error,
30 unsigned int nr_bytes, unsigned int bidi_bytes);
32 void blk_rq_timed_out_timer(unsigned long data);
33 void blk_delete_timer(struct request *);
34 void blk_add_timer(struct request *);
35 void __generic_unplug_device(struct request_queue *);
38 * Internal atomic flags for request handling
40 enum rq_atomic_flags {
41 REQ_ATOM_COMPLETE = 0,
45 * EH timer and IO completion will both attempt to 'grab' the request, make
46 * sure that only one of them succeeds
48 static inline int blk_mark_rq_complete(struct request *rq)
50 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
53 static inline void blk_clear_rq_complete(struct request *rq)
55 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
59 * Internal elevator interface
61 #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
63 void blk_insert_flush(struct request *rq);
64 void blk_abort_flushes(struct request_queue *q);
66 static inline struct request *__elv_next_request(struct request_queue *q)
68 struct request *rq;
70 while (1) {
71 if (!list_empty(&q->queue_head)) {
72 rq = list_entry_rq(q->queue_head.next);
73 return rq;
77 * Flush request is running and flush request isn't queueable
78 * in the drive, we can hold the queue till flush request is
79 * finished. Even we don't do this, driver can't dispatch next
80 * requests and will requeue them. And this can improve
81 * throughput too. For example, we have request flush1, write1,
82 * flush 2. flush1 is dispatched, then queue is hold, write1
83 * isn't inserted to queue. After flush1 is finished, flush2
84 * will be dispatched. Since disk cache is already clean,
85 * flush2 will be finished very soon, so looks like flush2 is
86 * folded to flush1.
87 * Since the queue is hold, a flag is set to indicate the queue
88 * should be restarted later. Please see flush_end_io() for
89 * details.
91 if (q->flush_pending_idx != q->flush_running_idx &&
92 !queue_flush_queueable(q)) {
93 q->flush_queue_delayed = 1;
94 return NULL;
96 if (unlikely(blk_queue_dead(q)) ||
97 !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
98 return NULL;
102 static inline void elv_activate_rq(struct request_queue *q, struct request *rq)
104 struct elevator_queue *e = q->elevator;
106 if (e->type->ops.elevator_activate_req_fn)
107 e->type->ops.elevator_activate_req_fn(q, rq);
110 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
112 struct elevator_queue *e = q->elevator;
114 if (e->type->ops.elevator_deactivate_req_fn)
115 e->type->ops.elevator_deactivate_req_fn(q, rq);
118 #ifdef CONFIG_FAIL_IO_TIMEOUT
119 int blk_should_fake_timeout(struct request_queue *);
120 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
121 ssize_t part_timeout_store(struct device *, struct device_attribute *,
122 const char *, size_t);
123 #else
124 static inline int blk_should_fake_timeout(struct request_queue *q)
126 return 0;
128 #endif
130 int ll_back_merge_fn(struct request_queue *q, struct request *req,
131 struct bio *bio);
132 int ll_front_merge_fn(struct request_queue *q, struct request *req,
133 struct bio *bio);
134 int attempt_back_merge(struct request_queue *q, struct request *rq);
135 int attempt_front_merge(struct request_queue *q, struct request *rq);
136 int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
137 struct request *next);
138 void blk_recalc_rq_segments(struct request *rq);
139 void blk_rq_set_mixed_merge(struct request *rq);
140 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
141 int blk_try_merge(struct request *rq, struct bio *bio);
143 void blk_queue_congestion_threshold(struct request_queue *q);
145 int blk_dev_init(void);
147 void elv_quiesce_start(struct request_queue *q);
148 void elv_quiesce_end(struct request_queue *q);
152 * Return the threshold (number of used requests) at which the queue is
153 * considered to be congested. It include a little hysteresis to keep the
154 * context switch rate down.
156 static inline int queue_congestion_on_threshold(struct request_queue *q)
158 return q->nr_congestion_on;
162 * The threshold at which a queue is considered to be uncongested
164 static inline int queue_congestion_off_threshold(struct request_queue *q)
166 return q->nr_congestion_off;
170 * Contribute to IO statistics IFF:
172 * a) it's attached to a gendisk, and
173 * b) the queue had IO stats enabled when this request was started, and
174 * c) it's a file system request or a discard request
176 static inline int blk_do_io_stat(struct request *rq)
178 return rq->rq_disk &&
179 (rq->cmd_flags & REQ_IO_STAT) &&
180 (rq->cmd_type == REQ_TYPE_FS ||
181 (rq->cmd_flags & REQ_DISCARD));
185 * Internal io_context interface
187 void get_io_context(struct io_context *ioc);
188 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
189 struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask);
190 void ioc_clear_queue(struct request_queue *q);
192 void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,
193 int node);
196 * create_io_context - try to create task->io_context
197 * @task: target task
198 * @gfp_mask: allocation mask
199 * @node: allocation node
201 * If @task->io_context is %NULL, allocate a new io_context and install it.
202 * Returns the current @task->io_context which may be %NULL if allocation
203 * failed.
205 * Note that this function can't be called with IRQ disabled because
206 * task_lock which protects @task->io_context is IRQ-unsafe.
208 static inline struct io_context *create_io_context(struct task_struct *task,
209 gfp_t gfp_mask, int node)
211 WARN_ON_ONCE(irqs_disabled());
212 if (unlikely(!task->io_context))
213 create_io_context_slowpath(task, gfp_mask, node);
214 return task->io_context;
218 * Internal throttling interface
220 #ifdef CONFIG_BLK_DEV_THROTTLING
221 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
222 extern void blk_throtl_drain(struct request_queue *q);
223 extern int blk_throtl_init(struct request_queue *q);
224 extern void blk_throtl_exit(struct request_queue *q);
225 extern void blk_throtl_release(struct request_queue *q);
226 #else /* CONFIG_BLK_DEV_THROTTLING */
227 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
229 return false;
231 static inline void blk_throtl_drain(struct request_queue *q) { }
232 static inline int blk_throtl_init(struct request_queue *q) { return 0; }
233 static inline void blk_throtl_exit(struct request_queue *q) { }
234 static inline void blk_throtl_release(struct request_queue *q) { }
235 #endif /* CONFIG_BLK_DEV_THROTTLING */
237 #endif /* BLK_INTERNAL_H */