| #ifndef __LINUX__AIO_H |
| #define __LINUX__AIO_H |
| |
| #include <linux/list.h> |
| #include <linux/workqueue.h> |
| #include <linux/aio_abi.h> |
| #include <linux/uio.h> |
| #include <linux/rcupdate.h> |
| |
| #include <linux/atomic.h> |
| |
| struct kioctx; |
| struct kiocb; |
| |
| #define KIOCB_KEY 0 |
| |
| /* |
| * We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either |
| * cancelled or completed (this makes a certain amount of sense because |
| * successful cancellation - io_cancel() - does deliver the completion to |
| * userspace). |
| * |
| * And since most things don't implement kiocb cancellation and we'd really like |
| * kiocb completion to be lockless when possible, we use ki_cancel to |
| * synchronize cancellation and completion - we only set it to KIOCB_CANCELLED |
| * with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel(). |
| */ |
| #define KIOCB_CANCELLED ((void *) (~0ULL)) |
| |
| typedef int (kiocb_cancel_fn)(struct kiocb *, struct io_event *); |
| |
| /* is there a better place to document function pointer methods? */ |
| /** |
| * ki_retry - iocb forward progress callback |
| * @kiocb: The kiocb struct to advance by performing an operation. |
| * |
| * This callback is called when the AIO core wants a given AIO operation |
| * to make forward progress. The kiocb argument describes the operation |
| * that is to be performed. As the operation proceeds, perhaps partially, |
| * ki_retry is expected to update the kiocb with progress made. Typically |
| * ki_retry is set in the AIO core and it itself calls file_operations |
| * helpers. |
| * |
| * ki_retry's return value determines when the AIO operation is completed |
| * and an event is generated in the AIO event ring. Except the special |
| * return values described below, the value that is returned from ki_retry |
| * is transferred directly into the completion ring as the operation's |
| * resulting status. Once this has happened ki_retry *MUST NOT* reference |
| * the kiocb pointer again. |
| * |
| * If ki_retry returns -EIOCBQUEUED it has made a promise that aio_complete() |
| * will be called on the kiocb pointer in the future. The AIO core will |
| * not ask the method again -- ki_retry must ensure forward progress. |
| * aio_complete() must be called once and only once in the future, multiple |
| * calls may result in undefined behaviour. |
| */ |
| struct kiocb { |
| atomic_t ki_users; |
| |
| struct file *ki_filp; |
| struct kioctx *ki_ctx; /* NULL for sync ops */ |
| kiocb_cancel_fn *ki_cancel; |
| ssize_t (*ki_retry)(struct kiocb *); |
| void (*ki_dtor)(struct kiocb *); |
| |
| union { |
| void __user *user; |
| struct task_struct *tsk; |
| } ki_obj; |
| |
| __u64 ki_user_data; /* user's data for completion */ |
| loff_t ki_pos; |
| |
| void *private; |
| /* State that we remember to be able to restart/retry */ |
| unsigned short ki_opcode; |
| size_t ki_nbytes; /* copy of iocb->aio_nbytes */ |
| char __user *ki_buf; /* remaining iocb->aio_buf */ |
| size_t ki_left; /* remaining bytes */ |
| struct iovec ki_inline_vec; /* inline vector */ |
| struct iovec *ki_iovec; |
| unsigned long ki_nr_segs; |
| unsigned long ki_cur_seg; |
| |
| struct list_head ki_list; /* the aio core uses this |
| * for cancellation */ |
| |
| /* |
| * If the aio_resfd field of the userspace iocb is not zero, |
| * this is the underlying eventfd context to deliver events to. |
| */ |
| struct eventfd_ctx *ki_eventfd; |
| }; |
| |
| static inline bool is_sync_kiocb(struct kiocb *kiocb) |
| { |
| return kiocb->ki_ctx == NULL; |
| } |
| |
| static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) |
| { |
| *kiocb = (struct kiocb) { |
| .ki_users = ATOMIC_INIT(1), |
| .ki_ctx = NULL, |
| .ki_filp = filp, |
| .ki_obj.tsk = current, |
| }; |
| } |
| |
| /* prototypes */ |
| #ifdef CONFIG_AIO |
| extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb); |
| extern void aio_put_req(struct kiocb *iocb); |
| extern void aio_complete(struct kiocb *iocb, long res, long res2); |
| struct mm_struct; |
| extern void exit_aio(struct mm_struct *mm); |
| extern long do_io_submit(aio_context_t ctx_id, long nr, |
| struct iocb __user *__user *iocbpp, bool compat); |
| void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel); |
| #else |
| static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; } |
| static inline void aio_put_req(struct kiocb *iocb) { } |
| static inline void aio_complete(struct kiocb *iocb, long res, long res2) { } |
| struct mm_struct; |
| static inline void exit_aio(struct mm_struct *mm) { } |
| static inline long do_io_submit(aio_context_t ctx_id, long nr, |
| struct iocb __user * __user *iocbpp, |
| bool compat) { return 0; } |
| static inline void kiocb_set_cancel_fn(struct kiocb *req, |
| kiocb_cancel_fn *cancel) { } |
| #endif /* CONFIG_AIO */ |
| |
| static inline struct kiocb *list_kiocb(struct list_head *h) |
| { |
| return list_entry(h, struct kiocb, ki_list); |
| } |
| |
| /* for sysctl: */ |
| extern unsigned long aio_nr; |
| extern unsigned long aio_max_nr; |
| |
| #endif /* __LINUX__AIO_H */ |