/*      $NetBSD: extent.h,v 1.26 2017/08/24 11:33:28 jmcneill Exp $     */

/*-
 * Copyright (c) 1996, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#ifndef _SYS_EXTENT_H_
#define _SYS_EXTENT_H_

#include <sys/queue.h>
#include <sys/mutex.h>
#include <sys/condvar.h>

#ifndef _KERNEL
#include <stdbool.h>
#endif

struct extent_region {
        LIST_ENTRY(extent_region) er_link;      /* link in region list */
        u_long  er_start;               /* start of region */
        u_long  er_end;                 /* end of region */
        int     er_flags;               /* misc. flags */
};

/* er_flags */
#define ER_ALLOC        0x01    /* region descriptor dynamically allocated */

struct extent {
        const char *ex_name;            /* name of extent */
        kmutex_t ex_lock;               /* lock on this extent */
        kcondvar_t ex_cv;               /* synchronization */
                                        /* allocated regions in extent */
        LIST_HEAD(, extent_region) ex_regions;
        u_long  ex_start;               /* start of extent */
        u_long  ex_end;                 /* end of extent */
        int     ex_flags;               /* misc. information */
        bool    ex_flwanted;            /* someone asleep on freelist */
};

struct extent_fixed {
        struct extent   fex_extent;     /* MUST BE FIRST */
                                        /* freelist of region descriptors */
        LIST_HEAD(, extent_region) fex_freelist;
        void *          fex_storage;    /* storage space for descriptors */
        size_t          fex_storagesize; /* size of storage space */
};

/* ex_flags; for internal use only */
#define EXF_FIXED       __BIT(0)        /* extent uses fixed storage */
#define EXF_NOCOALESCE  __BIT(1)        /* coalescing of regions not allowed */
#define EXF_EARLY       __BIT(2)        /* no need to lock */

#define EXF_BITS        "\20\3EARLY\2NOCOALESCE\1FIXED"

/* misc. flags passed to extent functions */
#define EX_NOWAIT       0               /* not safe to sleep */
#define EX_WAITOK       __BIT(0)        /* safe to sleep */
#define EX_FAST         __BIT(1)        /* take first fit in extent_alloc() */
#define EX_CATCH        __BIT(2)        /* catch signals while sleeping */
#define EX_NOCOALESCE   __BIT(3)        /* create a non-coalescing extent */
#define EX_MALLOCOK     __BIT(4)        /* safe to call kmem_alloc() */
#define EX_WAITSPACE    __BIT(5)        /* wait for space to become free */
#define EX_BOUNDZERO    __BIT(6)        /* boundary lines start at 0 */
#define EX_EARLY        __BIT(7)        /* safe for early kernel bootstrap */

/*
 * Special place holders for "alignment" and "boundary" arguments,
 * in the event the caller doesn't wish to use those features.
 */
#define EX_NOALIGN      1               /* don't do alignment */
#define EX_NOBOUNDARY   0               /* don't do boundary checking */

#if defined(_KERNEL) || defined(_EXTENT_TESTING)
#define EXTENT_FIXED_STORAGE_SIZE(_nregions)            \
        (ALIGN(sizeof(struct extent_fixed)) +           \
        ((ALIGN(sizeof(struct extent_region))) *        \
         (_nregions)))

struct  extent *extent_create(const char *, u_long, u_long,
            void *, size_t, int);
void    extent_destroy(struct extent *);
int     extent_alloc_subregion1(struct extent *, u_long, u_long,
            u_long, u_long, u_long, u_long, int, u_long *);
int     extent_alloc_subregion(struct extent *, u_long, u_long,
            u_long, u_long, u_long, int, u_long *);
int     extent_alloc_region(struct extent *, u_long, u_long, int);
int     extent_alloc1(struct extent *, u_long, u_long, u_long, u_long, int,
            u_long *);
int     extent_alloc(struct extent *, u_long, u_long, u_long, int, u_long *);
int     extent_free(struct extent *, u_long, u_long, int);
void    extent_print(struct extent *);
void    extent_init(void);

#endif /* _KERNEL || _EXTENT_TESTING */

#endif /* ! _SYS_EXTENT_H_ */