zfs/lib/libspl/include/sys/uio.h

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

#ifndef	_LIBSPL_SYS_UIO_H
#define	_LIBSPL_SYS_UIO_H

#include_next <sys/uio.h>

typedef struct iovec iovec_t;

typedef enum uio_rw {
	UIO_READ =	0,
	UIO_WRITE =	1,
} uio_rw_t;

typedef enum uio_seg {
	UIO_USERSPACE =	0,
	UIO_SYSSPACE =	1,
	UIO_USERISPACE = 2,
} uio_seg_t;

typedef struct uio {
	struct iovec	*uio_iov;	/* pointer to array of iovecs */
	int		uio_iovcnt;	/* number of iovecs */
	offset_t	uio_loffset;	/* file offset */
	uio_seg_t	uio_segflg;	/* address space (kernel or user) */
	uint16_t	uio_fmode;	/* file mode flags */
	uint16_t	uio_extflg;	/* extended flags */
	offset_t	uio_limit;	/* u-limit (maximum byte offset) */
	ssize_t		uio_resid;	/* residual count */
} uio_t;

typedef enum xuio_type {
	UIOTYPE_ASYNCIO,
	UIOTYPE_ZEROCOPY,
} xuio_type_t;

#define	UIOA_IOV_MAX	16

typedef struct uioa_page_s {		/* locked uio_iov state */
	int	uioa_pfncnt;		/* count of pfn_t(s) in *uioa_ppp */
	void	**uioa_ppp;		/* page_t or pfn_t array */
	caddr_t	uioa_base;		/* address base */
	size_t	uioa_len;		/* span length */
} uioa_page_t;

typedef struct xuio {
	uio_t xu_uio;				/* embedded UIO structure */

	/* Extended uio fields */
	enum xuio_type xu_type;			/* uio type */
	union {
		struct {
			uint32_t xu_a_state;	/* state of async i/o */
			ssize_t xu_a_mbytes;	/* bytes moved */
			uioa_page_t *xu_a_lcur;	/* uioa_locked[] pointer */
			void **xu_a_lppp;	/* lcur->uioa_pppp[] pointer */
			void *xu_a_hwst[4];	/* opaque hardware state */
			uioa_page_t xu_a_locked[UIOA_IOV_MAX];
		} xu_aio;

		struct {
			int xu_zc_rw;		/* read or write buffer */
			void *xu_zc_priv;	/* fs specific */
		} xu_zc;
	} xu_ext;
} xuio_t;

#define	XUIO_XUZC_PRIV(xuio)	xuio->xu_ext.xu_zc.xu_zc_priv
#define	XUIO_XUZC_RW(xuio)	xuio->xu_ext.xu_zc.xu_zc_rw

#endif	/* _SYS_UIO_H */