/*
 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com>
 * 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. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * $DragonFly: src/sys/sys/mpipe.h,v 1.2 2004/03/29 16:22:22 dillon Exp $
 */

#ifndef _SYS_MPIPE_H_
#define _SYS_MPIPE_H_

#ifndef _SYS_MALLOC_H_
#include <sys/malloc.h>
#endif

/*
 * Pipeline memory allocations with persistent store capabilities.  This
 * implements a pipeline for allocations of a particular size.  It is used
 * in order to allow memory allocations to block while at the same time
 * guarenteeing that no deadlocks will occur.
 *
 * By default new allocations are zero'd out. 
 *
 * MPF_NOZERO		If specified the underlying buffers are not zero'd.
 *			Note this also means you have no way of knowing which
 *			buffers are coming from the cache and which are new
 *			allocations.
 *
 * MPF_CACHEDATA	If specified the deconstructor will be called when
 *			the underlying buffer is free()'d, but the buffer may
 *			be reused many times before/if that happens.  The
 *			buffer is NOT zero'd on reuse regardless of the
 *			MPF_NOZERO flag.
 *
 *			If not specified and MPF_NOZERO is also not specified,
 *			then buffers reused from the cache will be zero'd as
 *			well as new allocations.
 *
 *			Note that the deconstructor function may still be NULL
 *			if this flag is specified, meaning that you don't need
 *			notification when the cached contents is physically
 *			free()'d.
 */
struct mpipe_buf;

struct malloc_pipe {
    malloc_type_t type;		/* malloc bucket */
    int		bytes;		/* allocation size */
    int		mpflags;	/* MPF_ flags */
    int		mflags;		/* M_ flags (used internally) */
    int		pending;	/* there is a request pending */
    int		free_count;	/* entries in array[] */
    int		total_count;	/* total outstanding allocations incl free */
    int		ary_count;	/* guarenteed allocation count */
    int		max_count;	/* maximum count (M_NOWAIT used beyond nom) */
    void	**array;	/* array[ary_count] */
    void	(*deconstruct)(struct malloc_pipe *, void *buf);
};

#define MPF_CACHEDATA		0x0001	/* cache old buffers (do not zero) */ 
#define MPF_NOZERO		0x0002	/* do not zero-out new allocations */

typedef struct malloc_pipe *malloc_pipe_t;

#ifdef _KERNEL

void mpipe_init(malloc_pipe_t mpipe, malloc_type_t type,
		int bytes, int nnom, int nmax, 
		int mpflags, void (*deconstruct)(struct malloc_pipe *, void *));
void mpipe_done(malloc_pipe_t mpipe);
void *mpipe_alloc_waitok(malloc_pipe_t mpipe);
void *mpipe_alloc_nowait(malloc_pipe_t mpipe);
void mpipe_free(malloc_pipe_t mpipe, void *vbuf);

#endif

#endif