/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 Ruslan Ermilov <ru@FreeBSD.org>
 * 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.
 */

#ifndef _G_CACHE_H_
#define _G_CACHE_H_

#include <sys/endian.h>

#define G_CACHE_CLASS_NAME      "CACHE"
#define G_CACHE_MAGIC           "GEOM::CACHE"
#define G_CACHE_VERSION         1

#ifdef _KERNEL
#define G_CACHE_TYPE_MANUAL     0
#define G_CACHE_TYPE_AUTOMATIC  1

#define G_CACHE_DEBUG(lvl, ...) \
    _GEOM_DEBUG("GEOM_CACHE", g_cache_debug, (lvl), NULL, __VA_ARGS__)
#define G_CACHE_LOGREQ(bp, ...) \
    _GEOM_DEBUG("GEOM_CACHE", g_cache_debug, 2, (bp), __VA_ARGS__)

#define G_CACHE_BUCKETS         (1 << 3)
#define G_CACHE_BUCKET(bno)     ((bno) & (G_CACHE_BUCKETS - 1))

struct g_cache_softc {
        struct g_geom   *sc_geom;
        int             sc_type;
        u_int           sc_bshift;
        u_int           sc_bsize;
        off_t           sc_tail;
        struct mtx      sc_mtx;
        struct callout  sc_callout;
        LIST_HEAD(, g_cache_desc) sc_desclist[G_CACHE_BUCKETS];
        TAILQ_HEAD(, g_cache_desc) sc_usedlist;
        uma_zone_t      sc_zone;

        u_int           sc_maxent;              /* max entries */
        u_int           sc_nent;                /* allocated entries */
        u_int           sc_nused;               /* re-useable entries */
        u_int           sc_invalid;             /* invalid entries */

        uintmax_t       sc_reads;               /* #reads */
        uintmax_t       sc_readbytes;           /* bytes read */
        uintmax_t       sc_cachereads;          /* #reads from cache */
        uintmax_t       sc_cachereadbytes;      /* bytes read from cache */
        uintmax_t       sc_cachehits;           /* cache hits */
        uintmax_t       sc_cachemisses;         /* cache misses */
        uintmax_t       sc_cachefull;           /* #times a cache was full */
        uintmax_t       sc_writes;              /* #writes */
        uintmax_t       sc_wrotebytes;          /* bytes written */
};
#define sc_name sc_geom->name

struct g_cache_desc {
        off_t           d_bno;                  /* block number */
        caddr_t         d_data;                 /* data area */
        struct bio      *d_biolist;             /* waiters */
        time_t          d_atime;                /* access time */
        int             d_flags;                /* flags */
#define D_FLAG_USED     (1 << 0)                        /* can be reused */
#define D_FLAG_INVALID  (1 << 1)                        /* invalid */
        LIST_ENTRY(g_cache_desc) d_next;        /* list */
        TAILQ_ENTRY(g_cache_desc) d_used;       /* used list */
};

#define G_CACHE_NEXT_BIO1(bp)   (bp)->bio_driver1
#define G_CACHE_NEXT_BIO2(bp)   (bp)->bio_driver2
#define G_CACHE_DESC1(bp)       (bp)->bio_caller1
#define G_CACHE_DESC2(bp)       (bp)->bio_caller2

#endif  /* _KERNEL */

struct g_cache_metadata {
        char            md_magic[16];           /* Magic value. */
        uint32_t        md_version;             /* Version number. */
        char            md_name[16];            /* Cache value. */
        uint32_t        md_bsize;               /* Cache block size. */
        uint32_t        md_size;                /* Cache size. */
        uint64_t        md_provsize;            /* Provider's size. */
};

static __inline void
cache_metadata_encode(const struct g_cache_metadata *md, u_char *data)
{

        bcopy(md->md_magic, data, sizeof(md->md_magic));
        le32enc(data + 16, md->md_version);
        bcopy(md->md_name, data + 20, sizeof(md->md_name));
        le32enc(data + 36, md->md_bsize);
        le32enc(data + 40, md->md_size);
        le64enc(data + 44, md->md_provsize);
}

static __inline void
cache_metadata_decode(const u_char *data, struct g_cache_metadata *md)
{

        bcopy(data, md->md_magic, sizeof(md->md_magic));
        md->md_version = le32dec(data + 16);
        bcopy(data + 20, md->md_name, sizeof(md->md_name));
        md->md_bsize = le32dec(data + 36);
        md->md_size = le32dec(data + 40);
        md->md_provsize = le64dec(data + 44);
}

#endif  /* _G_CACHE_H_ */