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
13 struct 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 */
85 struct 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 union {
98 void __user *user;
99 struct task_struct *tsk;
100 } ki_obj;
101
102 __u64 ki_user_data; /* user's data for completion */
103 wait_queue_t ki_wait;
104 loff_t ki_pos;
105
106 void *private;
107 /* State that we remember to be able to restart/retry */
108 unsigned short ki_opcode;
109 size_t ki_nbytes; /* copy of iocb->aio_nbytes */
110 char __user *ki_buf; /* remaining iocb->aio_buf */
111 size_t ki_left; /* remaining bytes */
112 long ki_retried; /* just for testing */
113 long ki_kicked; /* just for testing */
114 long ki_queued; /* just for testing */
115
116 struct list_head ki_list; /* the aio core uses this
117 * for cancellation */
118 };
119
120 #define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
121 #define init_sync_kiocb(x, filp) \
122 do { \
123 struct task_struct *tsk = current; \
124 (x)->ki_flags = 0; \
125 (x)->ki_users = 1; \
126 (x)->ki_key = KIOCB_SYNC_KEY; \
127 (x)->ki_filp = (filp); \
128 (x)->ki_ctx = NULL; \
129 (x)->ki_cancel = NULL; \
130 (x)->ki_retry = NULL; \
131 (x)->ki_dtor = NULL; \
132 (x)->ki_obj.tsk = tsk; \
133 (x)->ki_user_data = 0; \
134 init_wait((&(x)->ki_wait)); \
135 } while (0)
136
137 #define AIO_RING_MAGIC 0xa10a10a1
138 #define AIO_RING_COMPAT_FEATURES 1
139 #define AIO_RING_INCOMPAT_FEATURES 0
140 struct aio_ring {
141 unsigned id; /* kernel internal index number */
142 unsigned nr; /* number of io_events */
143 unsigned head;
144 unsigned tail;
145
146 unsigned magic;
147 unsigned compat_features;
148 unsigned incompat_features;
149 unsigned header_length; /* size of aio_ring */
150
151
152 struct io_event io_events[0];
153 }; /* 128 bytes + ring size */
154
155 #define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
156
157 #define AIO_RING_PAGES 8
158 struct aio_ring_info {
159 unsigned long mmap_base;
160 unsigned long mmap_size;
161
162 struct page **ring_pages;
163 spinlock_t ring_lock;
164 long nr_pages;
165
166 unsigned nr, tail;
167
168 struct page *internal_pages[AIO_RING_PAGES];
169 };
170
171 struct kioctx {
172 atomic_t users;
173 int dead;
174 struct mm_struct *mm;
175
176 /* This needs improving */
177 unsigned long user_id;
178 struct kioctx *next;
179
180 wait_queue_head_t wait;
181
182 spinlock_t ctx_lock;
183
184 int reqs_active;
185 struct list_head active_reqs; /* used for cancellation */
186 struct list_head run_list; /* used for kicked reqs */
187
188 /* sys_io_setup currently limits this to an unsigned int */
189 unsigned max_reqs;
190
191 struct aio_ring_info ring_info;
192
193 struct work_struct wq;
194 };
195
196 /* prototypes */
197 extern unsigned aio_max_size;
198
199 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
200 extern int FASTCALL(aio_put_req(struct kiocb *iocb));
201 extern void FASTCALL(kick_iocb(struct kiocb *iocb));
202 extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
203 extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
204 struct mm_struct;
205 extern void FASTCALL(exit_aio(struct mm_struct *mm));
206 extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
207 extern int FASTCALL(io_submit_one(struct kioctx *ctx,
208 struct iocb __user *user_iocb, struct iocb *iocb));
209
210 /* semi private, but used by the 32bit emulations: */
211 struct kioctx *lookup_ioctx(unsigned long ctx_id);
212 int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
213 struct iocb *iocb));
214
215 #define get_ioctx(kioctx) do { \
216 BUG_ON(unlikely(atomic_read(&(kioctx)->users) <= 0)); \
217 atomic_inc(&(kioctx)->users); \
218 } while (0)
219 #define put_ioctx(kioctx) do { \
220 BUG_ON(unlikely(atomic_read(&(kioctx)->users) <= 0)); \
221 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
222 __put_ioctx(kioctx); \
223 } while (0)
224
225 #define in_aio() !is_sync_wait(current->io_wait)
226 /* may be used for debugging */
227 #define warn_if_async() \
228 do { \
229 if (in_aio()) { \
230 printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
231 __FUNCTION__, __FILE__, __LINE__); \
232 dump_stack(); \
233 } \
234 } while (0)
235
236 #define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
237 #define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)
238
239 #include <linux/aio_abi.h>
240
241 static inline struct kiocb *list_kiocb(struct list_head *h)
242 {
243 return list_entry(h, struct kiocb, ki_list);
244 }
245
246 /* for sysctl: */
247 extern unsigned long aio_nr;
248 extern unsigned long aio_max_nr;
249
250 #endif /* __LINUX__AIO_H */
251
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