Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1#ifndef IOCONTEXT_H
2#define IOCONTEXT_H
3
4#include <linux/radix-tree.h>
5#include <linux/rcupdate.h>
6
7struct cfq_queue;
8struct cfq_ttime {
9 unsigned long last_end_request;
10
11 unsigned long ttime_total;
12 unsigned long ttime_samples;
13 unsigned long ttime_mean;
14};
15
16struct cfq_io_context {
17 void *key;
18
19 struct cfq_queue *cfqq[2];
20
21 struct io_context *ioc;
22
23 struct cfq_ttime ttime;
24
25 struct list_head queue_list;
26 struct hlist_node cic_list;
27
28 void (*dtor)(struct io_context *); /* destructor */
29 void (*exit)(struct io_context *); /* called on task exit */
30
31 struct rcu_head rcu_head;
32};
33
34/*
35 * I/O subsystem state of the associated processes. It is refcounted
36 * and kmalloc'ed. These could be shared between processes.
37 */
38struct io_context {
39 atomic_long_t refcount;
40 atomic_t nr_tasks;
41
42 /* all the fields below are protected by this lock */
43 spinlock_t lock;
44
45 unsigned short ioprio;
46 unsigned short ioprio_changed;
47
48#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
49 unsigned short cgroup_changed;
50#endif
51
52 /*
53 * For request batching
54 */
55 int nr_batch_requests; /* Number of requests left in the batch */
56 unsigned long last_waited; /* Time last woken after wait for request */
57
58 struct radix_tree_root radix_root;
59 struct hlist_head cic_list;
60 void __rcu *ioc_data;
61};
62
63static inline struct io_context *ioc_task_link(struct io_context *ioc)
64{
65 /*
66 * if ref count is zero, don't allow sharing (ioc is going away, it's
67 * a race).
68 */
69 if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
70 atomic_inc(&ioc->nr_tasks);
71 return ioc;
72 }
73
74 return NULL;
75}
76
77struct task_struct;
78#ifdef CONFIG_BLOCK
79int put_io_context(struct io_context *ioc);
80void exit_io_context(struct task_struct *task);
81struct io_context *get_io_context(gfp_t gfp_flags, int node);
82struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
83#else
84static inline void exit_io_context(struct task_struct *task)
85{
86}
87
88struct io_context;
89static inline int put_io_context(struct io_context *ioc)
90{
91 return 1;
92}
93#endif
94
95#endif