/*
 * Copyright (c) 2004 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Hiten Pandya <hmp@backplane.com> and Matthew Dillon
 * <dillon@backplane.com>.
 *
 * 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. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The MSF_BUF API is an augmentation similar to the SFBUF APIs and uses XIO
 * page array handling.  The SFBUF API originally came from:
 *
 *	Copyright (c) 2003 Alan L. Cox <alc@cs.rice.edu>.  All rights reserved.
 *	Copyright (c) 1998 David Greenman.  All rights reserved.
 *	src/sys/sys/sfbuf.h,v 1.4 2004/04/01 17:58:06 dillon
 *
 * $DragonFly: src/sys/sys/msfbuf.h,v 1.4 2004/07/12 06:17:03 hmp Exp $
 */
#ifndef _SYS_MSFBUF_H_
#define _SYS_MSFBUF_H_

#ifndef _SYS_QUEUE_H_
#include <sys/queue.h>
#endif

#ifndef _SYS_XIO_H_
#include <sys/xio.h>
#endif

/*
 * MSF_BUFs are used for caching ephermal mappings that span more than
 * one page.
 *
 * The interface returns an msf_buf data structure which has information
 * about managing the ephermal mapping, its KVA pointer and an embedded
 * XIO structure which describes the mapping.
 *
 * The embedded XIO structure be passed around to the DEV system because
 * it is ref-counted; thus making it perfectly usable by anything that
 * can accept an XIO as a transfer unit, most notably the buffer-cache
 * and the XIO API.
 *
 */

struct msf_buf {
	LIST_ENTRY(msf_buf)  active_list; /* active list of buffers */
	TAILQ_ENTRY(msf_buf) free_list;   /* free list of buffers */
	vm_offset_t 	m_kva;    	      /* KVA offset */
	cpumask_t    	m_cpumask;	      /* CPU mask for synchronization */
	struct xio  	m_xio;  	      /* xio embedded */
	int         	m_refcnt; 	      /* map usage tracking */
	int          	m_flags; 	      /* control flags */
};

#if defined(_KERNEL)

/*
 * Return a KVA offset to the client
 */
static __inline
vm_offset_t
msf_buf_kva(struct msf_buf *msf)
{
	return (msf->m_kva);
}

/*
 * Return a reference to the underlying pages of an MSF_BUF
 */
static __inline
vm_page_t *
msf_buf_pages(struct msf_buf *msf)
{
	return (msf->m_xio.xio_pages);
}

/* API function prototypes */
struct msf_buf 	*msf_buf_alloc(vm_page_t *pg_ary, int npages, int flags);
void        	 msf_buf_free(struct msf_buf *);
void         	 msf_buf_ref(struct msf_buf *);

#endif /* _KERNEL */

#endif