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 15 struct 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 */ 87 struct 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 void *private; 109 /* State that we remember to be able to restart/retry */ 110 unsigned short ki_opcode; 111 size_t ki_nbytes; /* copy of iocb->aio_nbytes */ 112 char __user *ki_buf; /* remaining iocb->aio_buf */ 113 size_t ki_left; /* remaining bytes */ 114 struct iovec ki_inline_vec; /* inline vector */ 115 struct iovec *ki_iovec; 116 unsigned long ki_nr_segs; 117 unsigned long ki_cur_seg; 118 119 struct list_head ki_list; /* the aio core uses this 120 * for cancellation */ 121 }; 122 123 #define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY) 124 #define init_sync_kiocb(x, filp) \ 125 do { \ 126 struct task_struct *tsk = current; \ 127 (x)->ki_flags = 0; \ 128 (x)->ki_users = 1; \ 129 (x)->ki_key = KIOCB_SYNC_KEY; \ 130 (x)->ki_filp = (filp); \ 131 (x)->ki_ctx = NULL; \ 132 (x)->ki_cancel = NULL; \ 133 (x)->ki_retry = NULL; \ 134 (x)->ki_dtor = NULL; \ 135 (x)->ki_obj.tsk = tsk; \ 136 (x)->ki_user_data = 0; \ 137 init_wait((&(x)->ki_wait)); \ 138 } while (0) 139 140 #define AIO_RING_MAGIC 0xa10a10a1 141 #define AIO_RING_COMPAT_FEATURES 1 142 #define AIO_RING_INCOMPAT_FEATURES 0 143 struct aio_ring { 144 unsigned id; /* kernel internal index number */ 145 unsigned nr; /* number of io_events */ 146 unsigned head; 147 unsigned tail; 148 149 unsigned magic; 150 unsigned compat_features; 151 unsigned incompat_features; 152 unsigned header_length; /* size of aio_ring */ 153 154 155 struct io_event io_events[0]; 156 }; /* 128 bytes + ring size */ 157 158 #define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr) 159 160 #define AIO_RING_PAGES 8 161 struct aio_ring_info { 162 unsigned long mmap_base; 163 unsigned long mmap_size; 164 165 struct page **ring_pages; 166 spinlock_t ring_lock; 167 long nr_pages; 168 169 unsigned nr, tail; 170 171 struct page *internal_pages[AIO_RING_PAGES]; 172 }; 173 174 struct kioctx { 175 atomic_t users; 176 int dead; 177 struct mm_struct *mm; 178 179 /* This needs improving */ 180 unsigned long user_id; 181 struct kioctx *next; 182 183 wait_queue_head_t wait; 184 185 spinlock_t ctx_lock; 186 187 int reqs_active; 188 struct list_head active_reqs; /* used for cancellation */ 189 struct list_head run_list; /* used for kicked reqs */ 190 191 /* sys_io_setup currently limits this to an unsigned int */ 192 unsigned max_reqs; 193 194 struct aio_ring_info ring_info; 195 196 struct delayed_work wq; 197 }; 198 199 /* prototypes */ 200 extern unsigned aio_max_size; 201 202 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb)); 203 extern int FASTCALL(aio_put_req(struct kiocb *iocb)); 204 extern void FASTCALL(kick_iocb(struct kiocb *iocb)); 205 extern int FASTCALL(aio_complete(struct kiocb *iocb, long res, long res2)); 206 extern void FASTCALL(__put_ioctx(struct kioctx *ctx)); 207 struct mm_struct; 208 extern void FASTCALL(exit_aio(struct mm_struct *mm)); 209 extern struct kioctx *lookup_ioctx(unsigned long ctx_id); 210 extern int FASTCALL(io_submit_one(struct kioctx *ctx, 211 struct iocb __user *user_iocb, struct iocb *iocb)); 212 213 /* semi private, but used by the 32bit emulations: */ 214 struct kioctx *lookup_ioctx(unsigned long ctx_id); 215 int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, 216 struct iocb *iocb)); 217 218 #define get_ioctx(kioctx) do { \ 219 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ 220 atomic_inc(&(kioctx)->users); \ 221 } while (0) 222 #define put_ioctx(kioctx) do { \ 223 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ 224 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \ 225 __put_ioctx(kioctx); \ 226 } while (0) 227 228 #define in_aio() !is_sync_wait(current->io_wait) 229 /* may be used for debugging */ 230 #define warn_if_async() \ 231 do { \ 232 if (in_aio()) { \ 233 printk(KERN_ERR "%s(%s:%d) called in async context!\n", \ 234 __FUNCTION__, __FILE__, __LINE__); \ 235 dump_stack(); \ 236 } \ 237 } while (0) 238 239 #define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait) 240 241 #include <linux/aio_abi.h> 242 243 static inline struct kiocb *list_kiocb(struct list_head *h) 244 { 245 return list_entry(h, struct kiocb, ki_list); 246 } 247 248 /* for sysctl: */ 249 extern unsigned long aio_nr; 250 extern unsigned long aio_max_nr; 251 252 #endif /* __LINUX__AIO_H */ 253