Line data Source code
1 : #ifndef IOCONTEXT_H
2 : #define IOCONTEXT_H
3 :
4 : #include <linux/radix-tree.h>
5 : #include <linux/rcupdate.h>
6 :
7 : struct cfq_queue;
8 : struct cfq_io_context {
9 : void *key;
10 : unsigned long dead_key;
11 :
12 : struct cfq_queue *cfqq[2];
13 :
14 : struct io_context *ioc;
15 :
16 : unsigned long last_end_request;
17 :
18 : unsigned long ttime_total;
19 : unsigned long ttime_samples;
20 : unsigned long ttime_mean;
21 :
22 : struct list_head queue_list;
23 : struct hlist_node cic_list;
24 :
25 : void (*dtor)(struct io_context *); /* destructor */
26 : void (*exit)(struct io_context *); /* called on task exit */
27 :
28 : struct rcu_head rcu_head;
29 : };
30 1 :
31 : /*
32 : * I/O subsystem state of the associated processes. It is refcounted
33 : * and kmalloc'ed. These could be shared between processes.
34 : */
35 : struct io_context {
36 : atomic_long_t refcount;
37 : atomic_t nr_tasks;
38 :
39 : /* all the fields below are protected by this lock */
40 : spinlock_t lock;
41 :
42 : unsigned short ioprio;
43 : unsigned short ioprio_changed;
44 :
45 : #ifdef CONFIG_BLK_CGROUP
46 : unsigned short cgroup_changed;
47 : #endif
48 :
49 : /*
50 : * For request batching
51 : */
52 : unsigned long last_waited; /* Time last woken after wait for request */
53 : int nr_batch_requests; /* Number of requests left in the batch */
54 :
55 : struct radix_tree_root radix_root;
56 : struct hlist_head cic_list;
57 : void *ioc_data;
58 : };
59 :
60 : static inline struct io_context *ioc_task_link(struct io_context *ioc)
61 : {
62 : /*
63 : * if ref count is zero, don't allow sharing (ioc is going away, it's
64 : * a race).
65 : */
66 : if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
67 : atomic_inc(&ioc->nr_tasks);
68 : return ioc;
69 : }
70 :
71 : return NULL;
72 : }
73 :
74 : struct task_struct;
75 : #ifdef CONFIG_BLOCK
76 : int put_io_context(struct io_context *ioc);
77 : void exit_io_context(struct task_struct *task);
78 : struct io_context *get_io_context(gfp_t gfp_flags, int node);
79 : struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
80 : void copy_io_context(struct io_context **pdst, struct io_context **psrc);
81 : #else
82 : static inline void exit_io_context(struct task_struct *task)
83 : {
84 : }
85 :
86 : struct io_context;
87 : static inline int put_io_context(struct io_context *ioc)
88 : {
89 : return 1;
90 : }
91 : #endif
92 :
93 : #endif
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