#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 kiocb {	struct file		*ki_filp;	struct kioctx		*ki_ctx;	/* NULL for sync ops */	kiocb_cancel_fn		*ki_cancel;	void			*private; 	union {		void __user		*user;		struct task_struct	*tsk;	} ki_obj; 	__u64			ki_user_data;	/* user's data for completion */	loff_t			ki_pos;	size_t			ki_nbytes;	/* copy of iocb->aio_nbytes */ 	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_ctx = NULL,			.ki_filp = filp,			.ki_obj.tsk = current,		};} /* prototypes */#ifdef CONFIG_AIOextern ssize_t wait_on_sync_kiocb(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);#elsestatic inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }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 */