/*-
* Copyright (c) 1997 John S. Dyson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. John S. Dyson's name may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* DISCLAIMER: This code isn't warranted to do anything useful. Anything
* bad that happens because of using this software isn't the responsibility
* of the author. This software is distributed AS-IS.
*
* $FreeBSD$
*/
#ifndef _SYS_AIO_H_
#define _SYS_AIO_H_
#include <sys/types.h>
#include <sys/signal.h>
#ifdef _KERNEL
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/signalvar.h>
#endif
/*
* Returned by aio_cancel:
*/
#define AIO_CANCELED 0x1
#define AIO_NOTCANCELED 0x2
#define AIO_ALLDONE 0x3
/*
* LIO opcodes
*/
#define LIO_NOP 0x0
#define LIO_WRITE 0x1
#define LIO_READ 0x2
#ifdef _KERNEL
#define LIO_SYNC 0x3
#define LIO_MLOCK 0x4
#endif
/*
* LIO modes
*/
#define LIO_NOWAIT 0x0
#define LIO_WAIT 0x1
/*
* Maximum number of allowed LIO operations
*/
#define AIO_LISTIO_MAX 16
#ifdef _KERNEL
/* Default values of tunables for the AIO worker pool. */
#ifndef MAX_AIO_PROCS
#define MAX_AIO_PROCS 32
#endif
#ifndef TARGET_AIO_PROCS
#define TARGET_AIO_PROCS 4
#endif
#ifndef AIOD_LIFETIME_DEFAULT
#define AIOD_LIFETIME_DEFAULT (30 * hz)
#endif
#endif
/*
* Private members for aiocb -- don't access
* directly.
*/
struct __aiocb_private {
long status;
long error;
void *kernelinfo;
};
/*
* I/O control block
*/
typedef struct aiocb {
int aio_fildes; /* File descriptor */
off_t aio_offset; /* File offset for I/O */
volatile void *aio_buf; /* I/O buffer in process space */
size_t aio_nbytes; /* Number of bytes for I/O */
int __spare__[2];
void *__spare2__;
int aio_lio_opcode; /* LIO opcode */
int aio_reqprio; /* Request priority -- ignored */
struct __aiocb_private _aiocb_private;
struct sigevent aio_sigevent; /* Signal to deliver */
} aiocb_t;
#ifdef _KERNEL
typedef void aio_cancel_fn_t(struct kaiocb *);
typedef void aio_handle_fn_t(struct kaiocb *);
/*
* Kernel version of an I/O control block.
*
* Locking key:
* * - need not protected
* a - locked by kaioinfo lock
* b - locked by backend lock
* c - locked by aio_job_mtx
*/
struct kaiocb {
TAILQ_ENTRY(kaiocb) list; /* (b) backend-specific list of jobs */
TAILQ_ENTRY(kaiocb) plist; /* (a) lists of pending / done jobs */
TAILQ_ENTRY(kaiocb) allist; /* (a) list of all jobs in proc */
int jobflags; /* (a) job flags */
int inblock; /* (*) input blocks */
int outblock; /* (*) output blocks */
int msgsnd; /* (*) messages sent */
int msgrcv; /* (*) messages received */
struct proc *userproc; /* (*) user process */
struct ucred *cred; /* (*) active credential when created */
struct file *fd_file; /* (*) pointer to file structure */
struct aioliojob *lio; /* (*) optional lio job */
struct aiocb *ujob; /* (*) pointer in userspace of aiocb */
struct knlist klist; /* (a) list of knotes */
struct aiocb uaiocb; /* (*) copy of user I/O control block */
ksiginfo_t ksi; /* (a) realtime signal info */
uint64_t seqno; /* (*) job number */
aio_cancel_fn_t *cancel_fn; /* (a) backend cancel function */
aio_handle_fn_t *handle_fn; /* (c) backend handle function */
union { /* Backend-specific data fields */
struct { /* BIO backend */
struct bio *bp; /* (*) BIO pointer */
struct buf *pbuf; /* (*) buffer pointer */
struct vm_page *pages[btoc(MAXPHYS)+1]; /* (*) */
int npages; /* (*) number of pages */
};
struct { /* fsync() requests */
int pending; /* (a) number of pending I/O */
};
struct {
void *backend1;
void *backend2;
long backend3;
int backend4;
};
};
};
struct socket;
struct sockbuf;
/*
* AIO backends should permit cancellation of queued requests waiting to
* be serviced by installing a cancel routine while the request is
* queued. The cancellation routine should dequeue the request if
* necessary and cancel it. Care must be used to handle races between
* queueing and dequeueing requests and cancellation.
*
* When queueing a request somewhere such that it can be cancelled, the
* caller should:
*
* 1) Acquire lock that protects the associated queue.
* 2) Call aio_set_cancel_function() to install the cancel routine.
* 3) If that fails, the request has a pending cancel and should be
* cancelled via aio_cancel().
* 4) Queue the request.
*
* When dequeueing a request to service it or hand it off to somewhere else,
* the caller should:
*
* 1) Acquire the lock that protects the associated queue.
* 2) Dequeue the request.
* 3) Call aio_clear_cancel_function() to clear the cancel routine.
* 4) If that fails, the cancel routine is about to be called. The
* caller should ignore the request.
*
* The cancel routine should:
*
* 1) Acquire the lock that protects the associated queue.
* 2) Call aio_cancel_cleared() to determine if the request is already
* dequeued due to a race with dequeueing thread.
* 3) If that fails, dequeue the request.
* 4) Cancel the request via aio_cancel().
*/
bool aio_cancel_cleared(struct kaiocb *job);
void aio_cancel(struct kaiocb *job);
bool aio_clear_cancel_function(struct kaiocb *job);
void aio_complete(struct kaiocb *job, long status, int error);
void aio_schedule(struct kaiocb *job, aio_handle_fn_t *func);
bool aio_set_cancel_function(struct kaiocb *job, aio_cancel_fn_t *func);
void aio_switch_vmspace(struct kaiocb *job);
#else /* !_KERNEL */
struct timespec;
__BEGIN_DECLS
/*
* Asynchronously read from a file
*/
int aio_read(struct aiocb *);
/*
* Asynchronously write to file
*/
int aio_write(struct aiocb *);
/*
* List I/O Asynchronously/synchronously read/write to/from file
* "lio_mode" specifies whether or not the I/O is synchronous.
* "acb_list" is an array of "nacb_listent" I/O control blocks.
* when all I/Os are complete, the optional signal "sig" is sent.
*/
int lio_listio(int, struct aiocb *__restrict const *__restrict, int,
struct sigevent *);
/*
* Get completion status
* returns EINPROGRESS until I/O is complete.
* this routine does not block.
*/
int aio_error(const struct aiocb *);
/*
* Finish up I/O, releasing I/O resources and returns the value
* that would have been associated with a synchronous I/O request.
* This routine must be called once and only once for each
* I/O control block who has had I/O associated with it.
*/
ssize_t aio_return(struct aiocb *);
/*
* Cancel I/O
*/
int aio_cancel(int, struct aiocb *);
/*
* Suspend until all specified I/O or timeout is complete.
*/
int aio_suspend(const struct aiocb * const[], int, const struct timespec *);
/*
* Asynchronous mlock
*/
int aio_mlock(struct aiocb *);
#ifdef __BSD_VISIBLE
ssize_t aio_waitcomplete(struct aiocb **, struct timespec *);
#endif
int aio_fsync(int op, struct aiocb *aiocbp);
__END_DECLS
#endif /* !_KERNEL */
#endif /* !_SYS_AIO_H_ */
