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 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 0 138 struct 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 8 156 struct 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 }; 168 169 struct 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 */ 194 extern unsigned aio_max_size; 195 196 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb)); 197 extern int FASTCALL(aio_put_req(struct kiocb *iocb)); 198 extern void FASTCALL(kick_iocb(struct kiocb *iocb)); 199 extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2)); 200 extern void FASTCALL(__put_ioctx(struct kioctx *ctx)); 201 struct mm_struct; 202 extern void FASTCALL(exit_aio(struct mm_struct *mm)); 203 extern struct kioctx *lookup_ioctx(unsigned long ctx_id); 204 extern 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: */ 208 struct kioctx *lookup_ioctx(unsigned long ctx_id); 209 int 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() \ 218 do { \ 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> 230 231 static inline struct kiocb *list_kiocb(struct list_head *h) 232 { 233 return list_entry(h, struct kiocb, ki_list); 234 } 235 236 /* for sysctl: */ 237 extern atomic_t aio_nr; 238 extern unsigned aio_max_nr; 239 240 #endif /* __LINUX__AIO_H */ 241