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 unsigned 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 * If the aio_resfd field of the userspace iocb is not zero, 124 * this is the underlying file* to deliver event to. 125 */ 126 struct file *ki_eventfd; 127 }; 128 129 #define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY) 130 #define init_sync_kiocb(x, filp) \ 131 do { \ 132 struct task_struct *tsk = current; \ 133 (x)->ki_flags = 0; \ 134 (x)->ki_users = 1; \ 135 (x)->ki_key = KIOCB_SYNC_KEY; \ 136 (x)->ki_filp = (filp); \ 137 (x)->ki_ctx = NULL; \ 138 (x)->ki_cancel = NULL; \ 139 (x)->ki_retry = NULL; \ 140 (x)->ki_dtor = NULL; \ 141 (x)->ki_obj.tsk = tsk; \ 142 (x)->ki_user_data = 0; \ 143 init_wait((&(x)->ki_wait)); \ 144 } while (0) 145 146 #define AIO_RING_MAGIC 0xa10a10a1 147 #define AIO_RING_COMPAT_FEATURES 1 148 #define AIO_RING_INCOMPAT_FEATURES 0 149 struct aio_ring { 150 unsigned id; /* kernel internal index number */ 151 unsigned nr; /* number of io_events */ 152 unsigned head; 153 unsigned tail; 154 155 unsigned magic; 156 unsigned compat_features; 157 unsigned incompat_features; 158 unsigned header_length; /* size of aio_ring */ 159 160 161 struct io_event io_events[0]; 162 }; /* 128 bytes + ring size */ 163 164 #define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr) 165 166 #define AIO_RING_PAGES 8 167 struct aio_ring_info { 168 unsigned long mmap_base; 169 unsigned long mmap_size; 170 171 struct page **ring_pages; 172 spinlock_t ring_lock; 173 long nr_pages; 174 175 unsigned nr, tail; 176 177 struct page *internal_pages[AIO_RING_PAGES]; 178 }; 179 180 struct kioctx { 181 atomic_t users; 182 int dead; 183 struct mm_struct *mm; 184 185 /* This needs improving */ 186 unsigned long user_id; 187 struct kioctx *next; 188 189 wait_queue_head_t wait; 190 191 spinlock_t ctx_lock; 192 193 int reqs_active; 194 struct list_head active_reqs; /* used for cancellation */ 195 struct list_head run_list; /* used for kicked reqs */ 196 197 /* sys_io_setup currently limits this to an unsigned int */ 198 unsigned max_reqs; 199 200 struct aio_ring_info ring_info; 201 202 struct delayed_work wq; 203 }; 204 205 /* prototypes */ 206 extern unsigned aio_max_size; 207 208 extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb); 209 extern int aio_put_req(struct kiocb *iocb); 210 extern void kick_iocb(struct kiocb *iocb); 211 extern int aio_complete(struct kiocb *iocb, long res, long res2); 212 extern void __put_ioctx(struct kioctx *ctx); 213 struct mm_struct; 214 extern void exit_aio(struct mm_struct *mm); 215 extern struct kioctx *lookup_ioctx(unsigned long ctx_id); 216 extern int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, 217 struct iocb *iocb); 218 219 /* semi private, but used by the 32bit emulations: */ 220 struct kioctx *lookup_ioctx(unsigned long ctx_id); 221 int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, 222 struct iocb *iocb); 223 224 #define get_ioctx(kioctx) do { \ 225 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ 226 atomic_inc(&(kioctx)->users); \ 227 } while (0) 228 #define put_ioctx(kioctx) do { \ 229 BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ 230 if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \ 231 __put_ioctx(kioctx); \ 232 } while (0) 233 234 #define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait) 235 236 #include <linux/aio_abi.h> 237 238 static inline struct kiocb *list_kiocb(struct list_head *h) 239 { 240 return list_entry(h, struct kiocb, ki_list); 241 } 242 243 /* for sysctl: */ 244 extern unsigned long aio_nr; 245 extern unsigned long aio_max_nr; 246 247 #endif /* __LINUX__AIO_H */ 248