aio.h
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#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_AIO
extern 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);
#else
static 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 */