Linux kernel mirror (for testing)
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linux
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
8#include <asm/atomic.h>
9
10#define AIO_MAXSEGS 4
11#define AIO_KIOGRP_NR_ATOMIC 8
12
13struct kioctx;
14
15/* Notes on cancelling a kiocb:
16 * If a kiocb is cancelled, aio_complete may return 0 to indicate
17 * that cancel has not yet disposed of the kiocb. All cancel
18 * operations *must* call aio_put_req to dispose of the kiocb
19 * to guard against races with the completion code.
20 */
21#define KIOCB_C_CANCELLED 0x01
22#define KIOCB_C_COMPLETE 0x02
23
24#define KIOCB_SYNC_KEY (~0U)
25
26/* ki_flags bits */
27/*
28 * This may be used for cancel/retry serialization in the future, but
29 * for now it's unused and we probably don't want modules to even
30 * think they can use it.
31 */
32/* #define KIF_LOCKED 0 */
33#define KIF_KICKED 1
34#define KIF_CANCELLED 2
35
36#define kiocbTryLock(iocb) test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
37#define kiocbTryKick(iocb) test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
38
39#define kiocbSetLocked(iocb) set_bit(KIF_LOCKED, &(iocb)->ki_flags)
40#define kiocbSetKicked(iocb) set_bit(KIF_KICKED, &(iocb)->ki_flags)
41#define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
42
43#define kiocbClearLocked(iocb) clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
44#define kiocbClearKicked(iocb) clear_bit(KIF_KICKED, &(iocb)->ki_flags)
45#define kiocbClearCancelled(iocb) clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
46
47#define kiocbIsLocked(iocb) test_bit(KIF_LOCKED, &(iocb)->ki_flags)
48#define kiocbIsKicked(iocb) test_bit(KIF_KICKED, &(iocb)->ki_flags)
49#define kiocbIsCancelled(iocb) test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
50
51/* is there a better place to document function pointer methods? */
52/**
53 * ki_retry - iocb forward progress callback
54 * @kiocb: The kiocb struct to advance by performing an operation.
55 *
56 * This callback is called when the AIO core wants a given AIO operation
57 * to make forward progress. The kiocb argument describes the operation
58 * that is to be performed. As the operation proceeds, perhaps partially,
59 * ki_retry is expected to update the kiocb with progress made. Typically
60 * ki_retry is set in the AIO core and it itself calls file_operations
61 * helpers.
62 *
63 * ki_retry's return value determines when the AIO operation is completed
64 * and an event is generated in the AIO event ring. Except the special
65 * return values described below, the value that is returned from ki_retry
66 * is transferred directly into the completion ring as the operation's
67 * resulting status. Once this has happened ki_retry *MUST NOT* reference
68 * the kiocb pointer again.
69 *
70 * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete()
71 * will be called on the kiocb pointer in the future. The AIO core will
72 * not ask the method again -- ki_retry must ensure forward progress.
73 * aio_complete() must be called once and only once in the future, multiple
74 * calls may result in undefined behaviour.
75 *
76 * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
77 * will be called on the kiocb pointer in the future. This may happen
78 * through generic helpers that associate kiocb->ki_wait with a wait
79 * queue head that ki_retry uses via current->io_wait. It can also happen
80 * with custom tracking and manual calls to kick_iocb(), though that is
81 * discouraged. In either case, kick_iocb() must be called once and only
82 * once. ki_retry must ensure forward progress, the AIO core will wait
83 * indefinitely for kick_iocb() to be called.
84 */
85struct kiocb {
86 struct list_head ki_run_list;
87 long ki_flags;
88 int ki_users;
89 unsigned ki_key; /* id of this request */
90
91 struct file *ki_filp;
92 struct kioctx *ki_ctx; /* may be NULL for sync ops */
93 int (*ki_cancel)(struct kiocb *, struct io_event *);
94 ssize_t (*ki_retry)(struct kiocb *);
95 void (*ki_dtor)(struct kiocb *);
96
97 struct list_head ki_list; /* the aio core uses this
98 * for cancellation */
99
100 union {
101 void __user *user;
102 struct task_struct *tsk;
103 } ki_obj;
104 __u64 ki_user_data; /* user's data for completion */
105 loff_t ki_pos;
106 /* State that we remember to be able to restart/retry */
107 unsigned short ki_opcode;
108 size_t ki_nbytes; /* copy of iocb->aio_nbytes */
109 char __user *ki_buf; /* remaining iocb->aio_buf */
110 size_t ki_left; /* remaining bytes */
111 wait_queue_t ki_wait;
112 long ki_retried; /* just for testing */
113 long ki_kicked; /* just for testing */
114 long ki_queued; /* just for testing */
115
116 void *private;
117};
118
119#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
120#define init_sync_kiocb(x, filp) \
121 do { \
122 struct task_struct *tsk = current; \
123 (x)->ki_flags = 0; \
124 (x)->ki_users = 1; \
125 (x)->ki_key = KIOCB_SYNC_KEY; \
126 (x)->ki_filp = (filp); \
127 (x)->ki_ctx = &tsk->active_mm->default_kioctx; \
128 (x)->ki_cancel = NULL; \
129 (x)->ki_dtor = NULL; \
130 (x)->ki_obj.tsk = tsk; \
131 (x)->ki_user_data = 0; \
132 init_wait((&(x)->ki_wait)); \
133 } while (0)
134
135#define AIO_RING_MAGIC 0xa10a10a1
136#define AIO_RING_COMPAT_FEATURES 1
137#define AIO_RING_INCOMPAT_FEATURES 0
138struct aio_ring {
139 unsigned id; /* kernel internal index number */
140 unsigned nr; /* number of io_events */
141 unsigned head;
142 unsigned tail;
143
144 unsigned magic;
145 unsigned compat_features;
146 unsigned incompat_features;
147 unsigned header_length; /* size of aio_ring */
148
149
150 struct io_event io_events[0];
151}; /* 128 bytes + ring size */
152
153#define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
154
155#define AIO_RING_PAGES 8
156struct aio_ring_info {
157 unsigned long mmap_base;
158 unsigned long mmap_size;
159
160 struct page **ring_pages;
161 spinlock_t ring_lock;
162 long nr_pages;
163
164 unsigned nr, tail;
165
166 struct page *internal_pages[AIO_RING_PAGES];
167};
168
169struct kioctx {
170 atomic_t users;
171 int dead;
172 struct mm_struct *mm;
173
174 /* This needs improving */
175 unsigned long user_id;
176 struct kioctx *next;
177
178 wait_queue_head_t wait;
179
180 spinlock_t ctx_lock;
181
182 int reqs_active;
183 struct list_head active_reqs; /* used for cancellation */
184 struct list_head run_list; /* used for kicked reqs */
185
186 unsigned max_reqs;
187
188 struct aio_ring_info ring_info;
189
190 struct work_struct wq;
191};
192
193/* prototypes */
194extern unsigned aio_max_size;
195
196extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
197extern int FASTCALL(aio_put_req(struct kiocb *iocb));
198extern void FASTCALL(kick_iocb(struct kiocb *iocb));
199extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
200extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
201struct mm_struct;
202extern void FASTCALL(exit_aio(struct mm_struct *mm));
203extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
204extern int FASTCALL(io_submit_one(struct kioctx *ctx,
205 struct iocb __user *user_iocb, struct iocb *iocb));
206
207/* semi private, but used by the 32bit emulations: */
208struct kioctx *lookup_ioctx(unsigned long ctx_id);
209int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
210 struct iocb *iocb));
211
212#define get_ioctx(kioctx) do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
213#define put_ioctx(kioctx) do { if (unlikely(atomic_dec_and_test(&(kioctx)->users))) __put_ioctx(kioctx); else if (unlikely(atomic_read(&(kioctx)->users) < 0)) BUG(); } while (0)
214
215#define in_aio() !is_sync_wait(current->io_wait)
216/* may be used for debugging */
217#define warn_if_async() \
218do { \
219 if (in_aio()) { \
220 printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
221 __FUNCTION__, __FILE__, __LINE__); \
222 dump_stack(); \
223 } \
224} while (0)
225
226#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
227#define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)
228
229#include <linux/aio_abi.h>
230
231static inline struct kiocb *list_kiocb(struct list_head *h)
232{
233 return list_entry(h, struct kiocb, ki_list);
234}
235
236/* for sysctl: */
237extern atomic_t aio_nr;
238extern unsigned aio_max_nr;
239
240#endif /* __LINUX__AIO_H */