]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blame - include/linux/aio.h
[PATCH] Streamline generic_file_* interfaces and filemap cleanups
[mirror_ubuntu-artful-kernel.git] / include / linux / aio.h
CommitLineData
1da177e4
LT
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>
027445c3 7#include <linux/uio.h>
1da177e4
LT
8
9#include <asm/atomic.h>
10
11#define AIO_MAXSEGS 4
12#define AIO_KIOGRP_NR_ATOMIC 8
13
14struct kioctx;
15
16/* Notes on cancelling a kiocb:
17 * If a kiocb is cancelled, aio_complete may return 0 to indicate
18 * that cancel has not yet disposed of the kiocb. All cancel
19 * operations *must* call aio_put_req to dispose of the kiocb
20 * to guard against races with the completion code.
21 */
22#define KIOCB_C_CANCELLED 0x01
23#define KIOCB_C_COMPLETE 0x02
24
25#define KIOCB_SYNC_KEY (~0U)
26
27/* ki_flags bits */
4faa5285
ZB
28/*
29 * This may be used for cancel/retry serialization in the future, but
30 * for now it's unused and we probably don't want modules to even
31 * think they can use it.
32 */
33/* #define KIF_LOCKED 0 */
1da177e4
LT
34#define KIF_KICKED 1
35#define KIF_CANCELLED 2
36
37#define kiocbTryLock(iocb) test_and_set_bit(KIF_LOCKED, &(iocb)->ki_flags)
38#define kiocbTryKick(iocb) test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags)
39
40#define kiocbSetLocked(iocb) set_bit(KIF_LOCKED, &(iocb)->ki_flags)
41#define kiocbSetKicked(iocb) set_bit(KIF_KICKED, &(iocb)->ki_flags)
42#define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags)
43
44#define kiocbClearLocked(iocb) clear_bit(KIF_LOCKED, &(iocb)->ki_flags)
45#define kiocbClearKicked(iocb) clear_bit(KIF_KICKED, &(iocb)->ki_flags)
46#define kiocbClearCancelled(iocb) clear_bit(KIF_CANCELLED, &(iocb)->ki_flags)
47
48#define kiocbIsLocked(iocb) test_bit(KIF_LOCKED, &(iocb)->ki_flags)
49#define kiocbIsKicked(iocb) test_bit(KIF_KICKED, &(iocb)->ki_flags)
50#define kiocbIsCancelled(iocb) test_bit(KIF_CANCELLED, &(iocb)->ki_flags)
51
897f15fb
ZB
52/* is there a better place to document function pointer methods? */
53/**
54 * ki_retry - iocb forward progress callback
55 * @kiocb: The kiocb struct to advance by performing an operation.
56 *
57 * This callback is called when the AIO core wants a given AIO operation
58 * to make forward progress. The kiocb argument describes the operation
59 * that is to be performed. As the operation proceeds, perhaps partially,
60 * ki_retry is expected to update the kiocb with progress made. Typically
61 * ki_retry is set in the AIO core and it itself calls file_operations
62 * helpers.
63 *
64 * ki_retry's return value determines when the AIO operation is completed
65 * and an event is generated in the AIO event ring. Except the special
66 * return values described below, the value that is returned from ki_retry
67 * is transferred directly into the completion ring as the operation's
68 * resulting status. Once this has happened ki_retry *MUST NOT* reference
69 * the kiocb pointer again.
70 *
71 * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete()
72 * will be called on the kiocb pointer in the future. The AIO core will
73 * not ask the method again -- ki_retry must ensure forward progress.
74 * aio_complete() must be called once and only once in the future, multiple
75 * calls may result in undefined behaviour.
76 *
77 * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb()
78 * will be called on the kiocb pointer in the future. This may happen
79 * through generic helpers that associate kiocb->ki_wait with a wait
80 * queue head that ki_retry uses via current->io_wait. It can also happen
81 * with custom tracking and manual calls to kick_iocb(), though that is
82 * discouraged. In either case, kick_iocb() must be called once and only
83 * once. ki_retry must ensure forward progress, the AIO core will wait
84 * indefinitely for kick_iocb() to be called.
85 */
1da177e4
LT
86struct kiocb {
87 struct list_head ki_run_list;
88 long ki_flags;
89 int ki_users;
90 unsigned ki_key; /* id of this request */
91
92 struct file *ki_filp;
93 struct kioctx *ki_ctx; /* may be NULL for sync ops */
94 int (*ki_cancel)(struct kiocb *, struct io_event *);
95 ssize_t (*ki_retry)(struct kiocb *);
96 void (*ki_dtor)(struct kiocb *);
97
1da177e4
LT
98 union {
99 void __user *user;
100 struct task_struct *tsk;
101 } ki_obj;
59d9136b 102
1da177e4 103 __u64 ki_user_data; /* user's data for completion */
59d9136b 104 wait_queue_t ki_wait;
1da177e4 105 loff_t ki_pos;
59d9136b
BL
106
107 void *private;
1da177e4
LT
108 /* State that we remember to be able to restart/retry */
109 unsigned short ki_opcode;
110 size_t ki_nbytes; /* copy of iocb->aio_nbytes */
111 char __user *ki_buf; /* remaining iocb->aio_buf */
112 size_t ki_left; /* remaining bytes */
1da177e4
LT
113 long ki_retried; /* just for testing */
114 long ki_kicked; /* just for testing */
115 long ki_queued; /* just for testing */
027445c3 116 struct iovec ki_inline_vec; /* inline vector */
1da177e4 117
59d9136b
BL
118 struct list_head ki_list; /* the aio core uses this
119 * for cancellation */
1da177e4
LT
120};
121
122#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
123#define init_sync_kiocb(x, filp) \
124 do { \
125 struct task_struct *tsk = current; \
126 (x)->ki_flags = 0; \
127 (x)->ki_users = 1; \
128 (x)->ki_key = KIOCB_SYNC_KEY; \
129 (x)->ki_filp = (filp); \
20dcae32 130 (x)->ki_ctx = NULL; \
1da177e4 131 (x)->ki_cancel = NULL; \
59d9136b 132 (x)->ki_retry = NULL; \
1da177e4
LT
133 (x)->ki_dtor = NULL; \
134 (x)->ki_obj.tsk = tsk; \
135 (x)->ki_user_data = 0; \
136 init_wait((&(x)->ki_wait)); \
137 } while (0)
138
139#define AIO_RING_MAGIC 0xa10a10a1
140#define AIO_RING_COMPAT_FEATURES 1
141#define AIO_RING_INCOMPAT_FEATURES 0
142struct aio_ring {
143 unsigned id; /* kernel internal index number */
144 unsigned nr; /* number of io_events */
145 unsigned head;
146 unsigned tail;
147
148 unsigned magic;
149 unsigned compat_features;
150 unsigned incompat_features;
151 unsigned header_length; /* size of aio_ring */
152
153
154 struct io_event io_events[0];
155}; /* 128 bytes + ring size */
156
157#define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr)
158
159#define AIO_RING_PAGES 8
160struct aio_ring_info {
161 unsigned long mmap_base;
162 unsigned long mmap_size;
163
164 struct page **ring_pages;
165 spinlock_t ring_lock;
166 long nr_pages;
167
168 unsigned nr, tail;
169
170 struct page *internal_pages[AIO_RING_PAGES];
171};
172
173struct kioctx {
174 atomic_t users;
175 int dead;
176 struct mm_struct *mm;
177
178 /* This needs improving */
179 unsigned long user_id;
180 struct kioctx *next;
181
182 wait_queue_head_t wait;
183
184 spinlock_t ctx_lock;
185
186 int reqs_active;
187 struct list_head active_reqs; /* used for cancellation */
188 struct list_head run_list; /* used for kicked reqs */
189
d55b5fda 190 /* sys_io_setup currently limits this to an unsigned int */
1da177e4
LT
191 unsigned max_reqs;
192
193 struct aio_ring_info ring_info;
194
195 struct work_struct wq;
196};
197
198/* prototypes */
199extern unsigned aio_max_size;
200
201extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
202extern int FASTCALL(aio_put_req(struct kiocb *iocb));
203extern void FASTCALL(kick_iocb(struct kiocb *iocb));
204extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2));
205extern void FASTCALL(__put_ioctx(struct kioctx *ctx));
206struct mm_struct;
207extern void FASTCALL(exit_aio(struct mm_struct *mm));
208extern struct kioctx *lookup_ioctx(unsigned long ctx_id);
209extern int FASTCALL(io_submit_one(struct kioctx *ctx,
210 struct iocb __user *user_iocb, struct iocb *iocb));
211
212/* semi private, but used by the 32bit emulations: */
213struct kioctx *lookup_ioctx(unsigned long ctx_id);
214int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
215 struct iocb *iocb));
216
5ef1c49f 217#define get_ioctx(kioctx) do { \
3a271111 218 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
5ef1c49f
ZB
219 atomic_inc(&(kioctx)->users); \
220} while (0)
221#define put_ioctx(kioctx) do { \
3a271111 222 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \
5ef1c49f
ZB
223 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
224 __put_ioctx(kioctx); \
225} while (0)
1da177e4
LT
226
227#define in_aio() !is_sync_wait(current->io_wait)
228/* may be used for debugging */
229#define warn_if_async() \
230do { \
231 if (in_aio()) { \
232 printk(KERN_ERR "%s(%s:%d) called in async context!\n", \
233 __FUNCTION__, __FILE__, __LINE__); \
234 dump_stack(); \
235 } \
236} while (0)
237
238#define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait)
239#define is_retried_kiocb(iocb) ((iocb)->ki_retried > 1)
240
241#include <linux/aio_abi.h>
242
243static inline struct kiocb *list_kiocb(struct list_head *h)
244{
245 return list_entry(h, struct kiocb, ki_list);
246}
247
248/* for sysctl: */
d55b5fda
ZB
249extern unsigned long aio_nr;
250extern unsigned long aio_max_nr;
1da177e4
LT
251
252#endif /* __LINUX__AIO_H */