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 11 #define AIO_MAXSEGS 4 12 #define AIO_KIOGRP_NR_ATOMIC 8 13 14 struct 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 */ 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 */ 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 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 */ 86 struct kiocb { 87 struct list_head ki_run_list; 88 unsigned 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 98 union { 99 void __user *user; 100 struct task_struct *tsk; 101 } ki_obj; 102 103 __u64 ki_user_data; /* user's data for completion */ 104 wait_queue_t ki_wait; 105 loff_t ki_pos; 106 107 void *private; 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 */ 113 struct iovec ki_inline_vec; /* inline vector */ 114 struct iovec *ki_iovec; 115 unsigned long ki_nr_segs; 116 unsigned long ki_cur_seg; 117 118 struct list_head ki_list; /* the aio core uses this 119 * for cancellation */ 120 121 /* 122 * If the aio_resfd field of the userspace iocb is not zero, 123 * this is the underlying file* to deliver event to. 124 */ 125 struct file *ki_eventfd; 126 }; 127 128 #define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY) 129 #define init_sync_kiocb(x, filp) \ 130 do { \ 131 struct task_struct *tsk = current; \ 132 (x)->ki_flags = 0; \ 133 (x)->ki_users = 1; \ 134 (x)->ki_key = KIOCB_SYNC_KEY; \ 135 (x)->ki_filp = (filp); \ 136 (x)->ki_ctx = NULL; \ 137 (x)->ki_cancel = NULL; \ 138 (x)->ki_retry = NULL; \ 139 (x)->ki_dtor = NULL; \ 140 (x)->ki_obj.tsk = tsk; \ 141 (x)->ki_user_data = 0; \ 142 init_wait((&(x)->ki_wait)); \ 143 } while (0) 144 145 #define AIO_RING_MAGIC 0xa10a10a1 146 #define AIO_RING_COMPAT_FEATURES 1 147 #define AIO_RING_INCOMPAT_FEATURES 0 148 struct aio_ring { 149 unsigned id; /* kernel internal index number */ 150 unsigned nr; /* number of io_events */ 151 unsigned head; 152 unsigned tail; 153 154 unsigned magic; 155 unsigned compat_features; 156 unsigned incompat_features; 157 unsigned header_length; /* size of aio_ring */ 158 159 160 struct io_event io_events[0]; 161 }; /* 128 bytes + ring size */ 162 163 #define aio_ring_avail(info, ring) (((ring)->head + (info)->nr - 1 - (ring)->tail) % (info)->nr) 164 165 #define AIO_RING_PAGES 8 166 struct aio_ring_info { 167 unsigned long mmap_base; 168 unsigned long mmap_size; 169 170 struct page **ring_pages; 171 spinlock_t ring_lock; 172 long nr_pages; 173 174 unsigned nr, tail; 175 176 struct page *internal_pages[AIO_RING_PAGES]; 177 }; 178 179 struct kioctx { 180 atomic_t users; 181 int dead; 182 struct mm_struct *mm; 183 184 /* This needs improving */ 185 unsigned long user_id; 186 struct kioctx *next; 187 188 wait_queue_head_t wait; 189 190 spinlock_t ctx_lock; 191 192 int reqs_active; 193 struct list_head active_reqs; /* used for cancellation */ 194 struct list_head run_list; /* used for kicked reqs */ 195 196 /* sys_io_setup currently limits this to an unsigned int */ 197 unsigned max_reqs; 198 199 struct aio_ring_info ring_info; 200 201 struct delayed_work wq; 202 }; 203 204 /* prototypes */ 205 extern unsigned aio_max_size; 206 207 #ifdef CONFIG_AIO 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 struct mm_struct; 213 extern void exit_aio(struct mm_struct *mm); 214 #else 215 static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; } 216 static inline int aio_put_req(struct kiocb *iocb) { return 0; } 217 static inline void kick_iocb(struct kiocb *iocb) { } 218 static inline int aio_complete(struct kiocb *iocb, long res, long res2) { return 0; } 219 struct mm_struct; 220 static inline void exit_aio(struct mm_struct *mm) { } 221 #endif /* CONFIG_AIO */ 222 223 #define io_wait_to_kiocb(wait) container_of(wait, struct kiocb, ki_wait) 224 225 #include <linux/aio_abi.h> 226 227 static inline struct kiocb *list_kiocb(struct list_head *h) 228 { 229 return list_entry(h, struct kiocb, ki_list); 230 } 231 232 /* for sysctl: */ 233 extern unsigned long aio_nr; 234 extern unsigned long aio_max_nr; 235 236 #endif /* __LINUX__AIO_H */ 237