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#include <linux/uio.h>
8
9#include <asm/atomic.h>
10#include <linux/uio.h>
11
12#define AIO_MAXSEGS 4
13#define AIO_KIOGRP_NR_ATOMIC 8
14
15struct kioctx;
16
17/* Notes on cancelling a kiocb:
18 * If a kiocb is cancelled, aio_complete may return 0 to indicate
19 * that cancel has not yet disposed of the kiocb. All cancel
20 * operations *must* call aio_put_req to dispose of the kiocb
21 * to guard against races with the completion code.
22 */
23#define KIOCB_C_CANCELLED 0x01
24#define KIOCB_C_COMPLETE 0x02
25
26#define KIOCB_SYNC_KEY (~0U)
27
28/* ki_flags bits */
29/*
30 * This may be used for cancel/retry serialization in the future, but
31 * for now it's unused and we probably don't want modules to even
32 * think they can use it.
33 */
34/* #define KIF_LOCKED 0 */
35#define KIF_KICKED 1
36#define KIF_CANCELLED 2
37
38#define kiocbTryLock(iocb) test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
39#define kiocbTryKick(iocb) test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
40
41#define kiocbSetLocked(iocb) set_bit(KIF_LOCKED, &(iocb)->ki_flags)
42#define kiocbSetKicked(iocb) set_bit(KIF_KICKED, &(iocb)->ki_flags)
43#define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
44
45#define kiocbClearLocked(iocb) clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
46#define kiocbClearKicked(iocb) clear_bit(KIF_KICKED, &(iocb)->ki_flags)
47#define kiocbClearCancelled(iocb) clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
48
49#define kiocbIsLocked(iocb) test_bit(KIF_LOCKED, &(iocb)->ki_flags)
50#define kiocbIsKicked(iocb) test_bit(KIF_KICKED, &(iocb)->ki_flags)
51#define kiocbIsCancelled(iocb) test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
52
53/* is there a better place to document function pointer methods? */
54/**
55 * ki_retry - iocb forward progress callback
56 * @kiocb: The kiocb struct to advance by performing an operation.
57 *
58 * This callback is called when the AIO core wants a given AIO operation
59 * to make forward progress. The kiocb argument describes the operation
60 * that is to be performed. As the operation proceeds, perhaps partially,
61 * ki_retry is expected to update the kiocb with progress made. Typically
62 * ki_retry is set in the AIO core and it itself calls file_operations
63 * helpers.
64 *
65 * ki_retry's return value determines when the AIO operation is completed
66 * and an event is generated in the AIO event ring. Except the special
67 * return values described below, the value that is returned from ki_retry
68 * is transferred directly into the completion ring as the operation's
69 * resulting status. Once this has happened ki_retry *MUST NOT* reference
70 * the kiocb pointer again.
71 *
72 * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete()
73 * will be called on the kiocb pointer in the future. The AIO core will
74 * not ask the method again -- ki_retry must ensure forward progress.
75 * aio_complete() must be called once and only once in the future, multiple
76 * calls may result in undefined behaviour.
77 *
78 * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
79 * will be called on the kiocb pointer in the future. This may happen
80 * through generic helpers that associate kiocb->ki_wait with a wait
81 * queue head that ki_retry uses via current->io_wait. It can also happen
82 * with custom tracking and manual calls to kick_iocb(), though that is
83 * discouraged. In either case, kick_iocb() must be called once and only
84 * once. ki_retry must ensure forward progress, the AIO core will wait
85 * indefinitely for kick_iocb() to be called.
86 */
87struct kiocb {
88 struct list_head ki_run_list;
89 long ki_flags;
90 int ki_users;
91 unsigned ki_key; /* id of this request */
92
93 struct file *ki_filp;
94 struct kioctx *ki_ctx; /* may be NULL for sync ops */
95 int (*ki_cancel)(struct kiocb *, struct io_event *);
96 ssize_t (*ki_retry)(struct kiocb *);
97 void (*ki_dtor)(struct kiocb *);
98
99 union {
100 void __user *user;
101 struct task_struct *tsk;
102 } ki_obj;
103
104 __u64 ki_user_data; /* user's data for completion */
105 wait_queue_t ki_wait;
106 loff_t ki_pos;
107
108 atomic_t ki_bio_count; /* num bio used for this iocb */
109 void *private;
110 /* State that we remember to be able to restart/retry */
111 unsigned short ki_opcode;
112 size_t ki_nbytes; /* copy of iocb->aio_nbytes */
113 char __user *ki_buf; /* remaining iocb->aio_buf */
114 size_t ki_left; /* remaining bytes */
115 struct iovec ki_inline_vec; /* inline vector */
116 struct iovec *ki_iovec;
117 unsigned long ki_nr_segs;
118 unsigned long ki_cur_seg;
119
120 struct list_head ki_list; /* the aio core uses this
121 * for cancellation */
122};
123
124#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
125#define init_sync_kiocb(x, filp) \
126 do { \
127 struct task_struct *tsk = current; \
128 (x)->ki_flags = 0; \
129 (x)->ki_users = 1; \
130 (x)->ki_key = KIOCB_SYNC_KEY; \
131 (x)->ki_filp = (filp); \
132 (x)->ki_ctx = NULL; \
133 (x)->ki_cancel = NULL; \
134 (x)->ki_retry = NULL; \
135 (x)->ki_dtor = NULL; \
136 (x)->ki_obj.tsk = tsk; \
137 (x)->ki_user_data = 0; \
138 init_wait((&(x)->ki_wait)); \
139 } while (0)
140
141#define AIO_RING_MAGIC 0xa10a10a1
142#define AIO_RING_COMPAT_FEATURES 1
143#define AIO_RING_INCOMPAT_FEATURES 0
144struct aio_ring {
145 unsigned id; /* kernel internal index number */
146 unsigned nr; /* number of io_events */
147 unsigned head;
148 unsigned tail;
149
150 unsigned magic;
151 unsigned compat_features;
152 unsigned incompat_features;
153 unsigned header_length; /* size of aio_ring */
154
155
156 struct io_event io_events[0];
157}; /* 128 bytes + ring size */
158
159#define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
160
161#define AIO_RING_PAGES 8
162struct aio_ring_info {
163 unsigned long mmap_base;
164 unsigned long mmap_size;
165
166 struct page **ring_pages;
167 spinlock_t ring_lock;
168 long nr_pages;
169
170 unsigned nr, tail;
171
172 struct page *internal_pages[AIO_RING_PAGES];
173};
174
175struct kioctx {
176 atomic_t users;
177 int dead;
178 struct mm_struct *mm;
179
180 /* This needs improving */
181 unsigned long user_id;
182 struct kioctx *next;
183
184 wait_queue_head_t wait;
185
186 spinlock_t ctx_lock;
187
188 int reqs_active;
189 struct list_head active_reqs; /* used for cancellation */
190 struct list_head run_list; /* used for kicked reqs */
191
192 /* sys_io_setup currently limits this to an unsigned int */
193 unsigned max_reqs;
194
195 struct aio_ring_info ring_info;
196
197 struct delayed_work wq;
198};
199
200/* prototypes */
201extern unsigned aio_max_size;
202
203extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
204extern int FASTCALL(aio_put_req(struct kiocb *iocb));
205extern void FASTCALL(kick_iocb(struct kiocb *iocb));
206extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
207extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
208struct mm_struct;
209extern void FASTCALL(exit_aio(struct mm_struct *mm));
210extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
211extern int FASTCALL(io_submit_one(struct kioctx *ctx,
212 struct iocb __user *user_iocb, struct iocb *iocb));
213
214/* semi private, but used by the 32bit emulations: */
215struct kioctx *lookup_ioctx(unsigned long ctx_id);
216int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
217 struct iocb *iocb));
218
219#define get_ioctx(kioctx) do { \
220 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
221 atomic_inc(&(kioctx)->users); \
222} while (0)
223#define put_ioctx(kioctx) do { \
224 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
225 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
226 __put_ioctx(kioctx); \
227} while (0)
228
229#define in_aio() !is_sync_wait(current->io_wait)
230/* may be used for debugging */
231#define warn_if_async() \
232do { \
233 if (in_aio()) { \
234 printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
235 __FUNCTION__, __FILE__, __LINE__); \
236 dump_stack(); \
237 } \
238} while (0)
239
240#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
241
242#include <linux/aio_abi.h>
243
244static inline struct kiocb *list_kiocb(struct list_head *h)
245{
246 return list_entry(h, struct kiocb, ki_list);
247}
248
249/* for sysctl: */
250extern unsigned long aio_nr;
251extern unsigned long aio_max_nr;
252
253#endif /* __LINUX__AIO_H */