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1#ifndef __LINUX__AIO_H
2#define __LINUX__AIO_H
3
4#include <linux/list.h>
5#include <linux/workqueue.h>
6#include <linux/aio_abi.h>
7#include <linux/uio.h>
8#include <linux/rcupdate.h>
9
10#include <linux/atomic.h>
11
12struct kioctx;
13struct kiocb;
14
15#define KIOCB_KEY 0
16
17/*
18 * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
19 * cancelled or completed (this makes a certain amount of sense because
20 * successful cancellation - io_cancel() - does deliver the completion to
21 * userspace).
22 *
23 * And since most things don't implement kiocb cancellation and we'd really like
24 * kiocb completion to be lockless when possible, we use ki_cancel to
25 * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
26 * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
27 */
28#define KIOCB_CANCELLED ((void *) (~0ULL))
29
30typedef int (kiocb_cancel_fn)(struct kiocb *, struct io_event *);
31
32struct kiocb {
33 atomic_t ki_users;
34
35 struct file *ki_filp;
36 struct kioctx *ki_ctx; /* NULL for sync ops */
37 kiocb_cancel_fn *ki_cancel;
38 void (*ki_dtor)(struct kiocb *);
39
40 union {
41 void __user *user;
42 struct task_struct *tsk;
43 } ki_obj;
44
45 __u64 ki_user_data; /* user's data for completion */
46 loff_t ki_pos;
47
48 void *private;
49 /* State that we remember to be able to restart/retry */
50 unsigned short ki_opcode;
51 size_t ki_nbytes; /* copy of iocb->aio_nbytes */
52 char __user *ki_buf; /* remaining iocb->aio_buf */
53 size_t ki_left; /* remaining bytes */
54 struct iovec ki_inline_vec; /* inline vector */
55 struct iovec *ki_iovec;
56 unsigned long ki_nr_segs;
57 unsigned long ki_cur_seg;
58
59 struct list_head ki_list; /* the aio core uses this
60 * for cancellation */
61
62 /*
63 * If the aio_resfd field of the userspace iocb is not zero,
64 * this is the underlying eventfd context to deliver events to.
65 */
66 struct eventfd_ctx *ki_eventfd;
67};
68
69static inline bool is_sync_kiocb(struct kiocb *kiocb)
70{
71 return kiocb->ki_ctx == NULL;
72}
73
74static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
75{
76 *kiocb = (struct kiocb) {
77 .ki_users = ATOMIC_INIT(1),
78 .ki_ctx = NULL,
79 .ki_filp = filp,
80 .ki_obj.tsk = current,
81 };
82}
83
84/* prototypes */
85#ifdef CONFIG_AIO
86extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
87extern void aio_put_req(struct kiocb *iocb);
88extern void aio_complete(struct kiocb *iocb, long res, long res2);
89struct mm_struct;
90extern void exit_aio(struct mm_struct *mm);
91extern long do_io_submit(aio_context_t ctx_id, long nr,
92 struct iocb __user *__user *iocbpp, bool compat);
93void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
94#else
95static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
96static inline void aio_put_req(struct kiocb *iocb) { }
97static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
98struct mm_struct;
99static inline void exit_aio(struct mm_struct *mm) { }
100static inline long do_io_submit(aio_context_t ctx_id, long nr,
101 struct iocb __user * __user *iocbpp,
102 bool compat) { return 0; }
103static inline void kiocb_set_cancel_fn(struct kiocb *req,
104 kiocb_cancel_fn *cancel) { }
105#endif /* CONFIG_AIO */
106
107static inline struct kiocb *list_kiocb(struct list_head *h)
108{
109 return list_entry(h, struct kiocb, ki_list);
110}
111
112/* for sysctl: */
113extern unsigned long aio_nr;
114extern unsigned long aio_max_nr;
115
116#endif /* __LINUX__AIO_H */