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 #include <linux/rcupdate.h> 9 10 #include <linux/atomic.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 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 struct list_head ki_batch; /* batch allocation */ 121 122 /* 123 * If the aio_resfd field of the userspace iocb is not zero, 124 * this is the underlying eventfd context to deliver events to. 125 */ 126 struct eventfd_ctx *ki_eventfd; 127 }; 128 129 static inline bool is_sync_kiocb(struct kiocb *kiocb) 130 { 131 return kiocb->ki_key == KIOCB_SYNC_KEY; 132 } 133 134 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) 135 { 136 *kiocb = (struct kiocb) { 137 .ki_users = 1, 138 .ki_key = KIOCB_SYNC_KEY, 139 .ki_filp = filp, 140 .ki_obj.tsk = current, 141 }; 142 } 143 144 #define AIO_RING_MAGIC 0xa10a10a1 145 #define AIO_RING_COMPAT_FEATURES 1 146 #define AIO_RING_INCOMPAT_FEATURES 0 147 struct aio_ring { 148 unsigned id; /* kernel internal index number */ 149 unsigned nr; /* number of io_events */ 150 unsigned head; 151 unsigned tail; 152 153 unsigned magic; 154 unsigned compat_features; 155 unsigned incompat_features; 156 unsigned header_length; /* size of aio_ring */ 157 158 159 struct io_event io_events[0]; 160 }; /* 128 bytes + ring size */ 161 162 #define AIO_RING_PAGES 8 163 struct aio_ring_info { 164 unsigned long mmap_base; 165 unsigned long mmap_size; 166 167 struct page **ring_pages; 168 spinlock_t ring_lock; 169 long nr_pages; 170 171 unsigned nr, tail; 172 173 struct page *internal_pages[AIO_RING_PAGES]; 174 }; 175 176 static inline unsigned aio_ring_avail(struct aio_ring_info *info, 177 struct aio_ring *ring) 178 { 179 return (ring->head + info->nr - 1 - ring->tail) % info->nr; 180 } 181 182 struct kioctx { 183 atomic_t users; 184 int dead; 185 struct mm_struct *mm; 186 187 /* This needs improving */ 188 unsigned long user_id; 189 struct hlist_node list; 190 191 wait_queue_head_t wait; 192 193 spinlock_t ctx_lock; 194 195 int reqs_active; 196 struct list_head active_reqs; /* used for cancellation */ 197 struct list_head run_list; /* used for kicked reqs */ 198 199 /* sys_io_setup currently limits this to an unsigned int */ 200 unsigned max_reqs; 201 202 struct aio_ring_info ring_info; 203 204 struct delayed_work wq; 205 206 struct rcu_head rcu_head; 207 }; 208 209 /* prototypes */ 210 extern unsigned aio_max_size; 211 212 #ifdef CONFIG_AIO 213 extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb); 214 extern int aio_put_req(struct kiocb *iocb); 215 extern void kick_iocb(struct kiocb *iocb); 216 extern int aio_complete(struct kiocb *iocb, long res, long res2); 217 struct mm_struct; 218 extern void exit_aio(struct mm_struct *mm); 219 extern long do_io_submit(aio_context_t ctx_id, long nr, 220 struct iocb __user *__user *iocbpp, bool compat); 221 #else 222 static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; } 223 static inline int aio_put_req(struct kiocb *iocb) { return 0; } 224 static inline void kick_iocb(struct kiocb *iocb) { } 225 static inline int aio_complete(struct kiocb *iocb, long res, long res2) { return 0; } 226 struct mm_struct; 227 static inline void exit_aio(struct mm_struct *mm) { } 228 static inline long do_io_submit(aio_context_t ctx_id, long nr, 229 struct iocb __user * __user *iocbpp, 230 bool compat) { return 0; } 231 #endif /* CONFIG_AIO */ 232 233 static inline struct kiocb *list_kiocb(struct list_head *h) 234 { 235 return list_entry(h, struct kiocb, ki_list); 236 } 237 238 /* for sysctl: */ 239 extern unsigned long aio_nr; 240 extern unsigned long aio_max_nr; 241 242 #endif /* __LINUX__AIO_H */ 243