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 struct kioctx; 13 14 #define KIOCB_SYNC_KEY (~0U) 15 16 /* ki_flags bits */ 17 #define KIF_KICKED 1 18 #define KIF_CANCELLED 2 19 20 #define kiocbTryKick(iocb) test_and_set_bit(KIF_KICKED, &(iocb)->ki_flags) 21 22 #define kiocbSetKicked(iocb) set_bit(KIF_KICKED, &(iocb)->ki_flags) 23 #define kiocbSetCancelled(iocb) set_bit(KIF_CANCELLED, &(iocb)->ki_flags) 24 25 #define kiocbClearKicked(iocb) clear_bit(KIF_KICKED, &(iocb)->ki_flags) 26 #define kiocbClearCancelled(iocb) clear_bit(KIF_CANCELLED, &(iocb)->ki_flags) 27 28 #define kiocbIsKicked(iocb) test_bit(KIF_KICKED, &(iocb)->ki_flags) 29 #define kiocbIsCancelled(iocb) test_bit(KIF_CANCELLED, &(iocb)->ki_flags) 30 31 /* is there a better place to document function pointer methods? */ 32 /** 33 * ki_retry - iocb forward progress callback 34 * @kiocb: The kiocb struct to advance by performing an operation. 35 * 36 * This callback is called when the AIO core wants a given AIO operation 37 * to make forward progress. The kiocb argument describes the operation 38 * that is to be performed. As the operation proceeds, perhaps partially, 39 * ki_retry is expected to update the kiocb with progress made. Typically 40 * ki_retry is set in the AIO core and it itself calls file_operations 41 * helpers. 42 * 43 * ki_retry's return value determines when the AIO operation is completed 44 * and an event is generated in the AIO event ring. Except the special 45 * return values described below, the value that is returned from ki_retry 46 * is transferred directly into the completion ring as the operation's 47 * resulting status. Once this has happened ki_retry *MUST NOT* reference 48 * the kiocb pointer again. 49 * 50 * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete() 51 * will be called on the kiocb pointer in the future. The AIO core will 52 * not ask the method again -- ki_retry must ensure forward progress. 53 * aio_complete() must be called once and only once in the future, multiple 54 * calls may result in undefined behaviour. 55 * 56 * If ki_retry returns -EIOCBRETRY it has made a promise that kick_iocb() 57 * will be called on the kiocb pointer in the future. This may happen 58 * through generic helpers that associate kiocb->ki_wait with a wait 59 * queue head that ki_retry uses via current->io_wait. It can also happen 60 * with custom tracking and manual calls to kick_iocb(), though that is 61 * discouraged. In either case, kick_iocb() must be called once and only 62 * once. ki_retry must ensure forward progress, the AIO core will wait 63 * indefinitely for kick_iocb() to be called. 64 */ 65 struct kiocb { 66 struct list_head ki_run_list; 67 unsigned long ki_flags; 68 int ki_users; 69 unsigned ki_key; /* id of this request */ 70 71 struct file *ki_filp; 72 struct kioctx *ki_ctx; /* may be NULL for sync ops */ 73 int (*ki_cancel)(struct kiocb *, struct io_event *); 74 ssize_t (*ki_retry)(struct kiocb *); 75 void (*ki_dtor)(struct kiocb *); 76 77 union { 78 void __user *user; 79 struct task_struct *tsk; 80 } ki_obj; 81 82 __u64 ki_user_data; /* user's data for completion */ 83 loff_t ki_pos; 84 85 void *private; 86 /* State that we remember to be able to restart/retry */ 87 unsigned short ki_opcode; 88 size_t ki_nbytes; /* copy of iocb->aio_nbytes */ 89 char __user *ki_buf; /* remaining iocb->aio_buf */ 90 size_t ki_left; /* remaining bytes */ 91 struct iovec ki_inline_vec; /* inline vector */ 92 struct iovec *ki_iovec; 93 unsigned long ki_nr_segs; 94 unsigned long ki_cur_seg; 95 96 struct list_head ki_list; /* the aio core uses this 97 * for cancellation */ 98 struct list_head ki_batch; /* batch allocation */ 99 100 /* 101 * If the aio_resfd field of the userspace iocb is not zero, 102 * this is the underlying eventfd context to deliver events to. 103 */ 104 struct eventfd_ctx *ki_eventfd; 105 }; 106 107 static inline bool is_sync_kiocb(struct kiocb *kiocb) 108 { 109 return kiocb->ki_key == KIOCB_SYNC_KEY; 110 } 111 112 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) 113 { 114 *kiocb = (struct kiocb) { 115 .ki_users = 1, 116 .ki_key = KIOCB_SYNC_KEY, 117 .ki_filp = filp, 118 .ki_obj.tsk = current, 119 }; 120 } 121 122 #define AIO_RING_MAGIC 0xa10a10a1 123 #define AIO_RING_COMPAT_FEATURES 1 124 #define AIO_RING_INCOMPAT_FEATURES 0 125 struct aio_ring { 126 unsigned id; /* kernel internal index number */ 127 unsigned nr; /* number of io_events */ 128 unsigned head; 129 unsigned tail; 130 131 unsigned magic; 132 unsigned compat_features; 133 unsigned incompat_features; 134 unsigned header_length; /* size of aio_ring */ 135 136 137 struct io_event io_events[0]; 138 }; /* 128 bytes + ring size */ 139 140 #define AIO_RING_PAGES 8 141 struct aio_ring_info { 142 unsigned long mmap_base; 143 unsigned long mmap_size; 144 145 struct page **ring_pages; 146 spinlock_t ring_lock; 147 long nr_pages; 148 149 unsigned nr, tail; 150 151 struct page *internal_pages[AIO_RING_PAGES]; 152 }; 153 154 static inline unsigned aio_ring_avail(struct aio_ring_info *info, 155 struct aio_ring *ring) 156 { 157 return (ring->head + info->nr - 1 - ring->tail) % info->nr; 158 } 159 160 struct kioctx { 161 atomic_t users; 162 int dead; 163 struct mm_struct *mm; 164 165 /* This needs improving */ 166 unsigned long user_id; 167 struct hlist_node list; 168 169 wait_queue_head_t wait; 170 171 spinlock_t ctx_lock; 172 173 int reqs_active; 174 struct list_head active_reqs; /* used for cancellation */ 175 struct list_head run_list; /* used for kicked reqs */ 176 177 /* sys_io_setup currently limits this to an unsigned int */ 178 unsigned max_reqs; 179 180 struct aio_ring_info ring_info; 181 182 struct delayed_work wq; 183 184 struct rcu_head rcu_head; 185 }; 186 187 /* prototypes */ 188 #ifdef CONFIG_AIO 189 extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb); 190 extern int aio_put_req(struct kiocb *iocb); 191 extern void kick_iocb(struct kiocb *iocb); 192 extern int aio_complete(struct kiocb *iocb, long res, long res2); 193 struct mm_struct; 194 extern void exit_aio(struct mm_struct *mm); 195 extern long do_io_submit(aio_context_t ctx_id, long nr, 196 struct iocb __user *__user *iocbpp, bool compat); 197 #else 198 static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; } 199 static inline int aio_put_req(struct kiocb *iocb) { return 0; } 200 static inline void kick_iocb(struct kiocb *iocb) { } 201 static inline int aio_complete(struct kiocb *iocb, long res, long res2) { return 0; } 202 struct mm_struct; 203 static inline void exit_aio(struct mm_struct *mm) { } 204 static inline long do_io_submit(aio_context_t ctx_id, long nr, 205 struct iocb __user * __user *iocbpp, 206 bool compat) { return 0; } 207 #endif /* CONFIG_AIO */ 208 209 static inline struct kiocb *list_kiocb(struct list_head *h) 210 { 211 return list_entry(h, struct kiocb, ki_list); 212 } 213 214 /* for sysctl: */ 215 extern unsigned long aio_nr; 216 extern unsigned long aio_max_nr; 217 218 #endif /* __LINUX__AIO_H */ 219