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_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
31/*
32 * I/O subsystem state of the associated processes. It is refcounted
33 * and kmalloc'ed. These could be shared between processes.
34 */
35struct 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#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
46 unsigned short cgroup_changed;
47#endif
48
49 /*
50 * For request batching
51 */
52 int nr_batch_requests; /* Number of requests left in the batch */
53 unsigned long last_waited; /* Time last woken after wait for request */
54
55 struct radix_tree_root radix_root;
56 struct hlist_head cic_list;
57 void *ioc_data;
58};
59
60static 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
74struct task_struct;
75#ifdef CONFIG_BLOCK
76int put_io_context(struct io_context *ioc);
77void exit_io_context(struct task_struct *task);
78struct io_context *get_io_context(gfp_t gfp_flags, int node);
79struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
80void copy_io_context(struct io_context **pdst, struct io_context **psrc);
81#else
82static inline void exit_io_context(struct task_struct *task)
83{
84}
85
86struct io_context;
87static inline int put_io_context(struct io_context *ioc)
88{
89 return 1;
90}
91#endif
92
93#endif