/*
 * 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 (c) 1998,2001 by Sun Microsystems, Inc.
 * All rights reserved.
 *
 */

#include <sys/types.h>
#include <sys/cmn_err.h>
#include <sys/kmem.h>
#include <sys/systm.h>
#include <sys/debug.h>
#include <sys/ddi.h>

#include <sys/fdbuffer.h>

#ifdef DEBUG
static int fdb_debug;
#define FDB_D_CREATE    001
#define FDB_D_ALLOC     002
#define FDB_D_IO        004
#define FDB_D_ASYNC     010
#define DEBUGF(lvl, args)       { if ((lvl) & fdb_debug) cmn_err args; }
#else
#define DEBUGF(level, args)
#endif
static struct kmem_cache *fdb_cache;
static void fdb_zero_holes(fdbuffer_t *fdb);

/* ARGSUSED */
static int
fdb_cache_constructor(void *buf, void *cdrarg, int kmflags)
{
        fdbuffer_t *fdb = buf;

        mutex_init(&fdb->fd_mutex, NULL, MUTEX_DEFAULT, NULL);

        return (0);
}

/* ARGSUSED */
static void
fdb_cache_destructor(void *buf, void *cdrarg)
{
        fdbuffer_t *fdb = buf;

        mutex_destroy(&fdb->fd_mutex);
}

void
fdb_init()
{
        fdb_cache = kmem_cache_create("fdb_cache", sizeof (fdbuffer_t),
            0, fdb_cache_constructor, fdb_cache_destructor,
            NULL, NULL, NULL, 0);
}

static void
fdb_prepare(fdbuffer_t *fdb)
{
        fdb->fd_holes = NULL;
        fdb->fd_iofunc = NULL;
        fdb->fd_iargp = NULL;
        fdb->fd_parentbp = NULL;
        fdb->fd_resid = 0;
        fdb->fd_iocount = 0;
        fdb->fd_iodispatch = 0;
        fdb->fd_err = 0;
}

fdbuffer_t *
fdb_page_create(page_t *pp, size_t len, int flags)
{
        fdbuffer_t *fdb;

        DEBUGF(FDB_D_CREATE, (CE_NOTE,
            "?fdb_page_create: pp: %p len: %lux flags: %x",
            (void *)pp, len, flags));

        ASSERT(flags & (FDB_READ|FDB_WRITE));

        fdb = kmem_cache_alloc(fdb_cache, KM_SLEEP);

        fdb_prepare(fdb);

        fdb->fd_type = FDB_PAGEIO;
        fdb->fd_len = len;
        fdb->fd_state = flags;
        fdb->fd_pages = pp;

        return (fdb);
}

fdbuffer_t *
fdb_addr_create(
        caddr_t addr,
        size_t len,
        int flags,
        page_t **pplist,
        struct proc *procp)
{
        fdbuffer_t *fdb;

        DEBUGF(FDB_D_CREATE, (CE_NOTE,
            "?fdb_addr_create: addr: %p len: %lux flags: %x",
            (void *)addr, len, flags));

        ASSERT(flags & (FDB_READ|FDB_WRITE));

        fdb = kmem_cache_alloc(fdb_cache, KM_SLEEP);

        fdb_prepare(fdb);

        fdb->fd_type = FDB_VADDR;
        fdb->fd_len = len;
        fdb->fd_state = flags;
        fdb->fd_addr = addr;
        fdb->fd_shadow = pplist;
        fdb->fd_procp = procp;

        return (fdb);
}

void
fdb_set_iofunc(fdbuffer_t *fdb, fdb_iodone_t iofunc, void *ioargp, int flag)
{
        ASSERT(fdb);
        ASSERT(iofunc);
        ASSERT((flag & ~FDB_ICALLBACK) == 0);

        fdb->fd_iofunc = iofunc;
        fdb->fd_iargp = ioargp;

        mutex_enter(&fdb->fd_mutex);

        if (flag & FDB_ICALLBACK)
                fdb->fd_state |= FDB_ICALLBACK;

        fdb->fd_state |= FDB_ASYNC;

        mutex_exit(&fdb->fd_mutex);
}

int
fdb_get_error(fdbuffer_t *fdb)
{
        return (fdb->fd_err);
}

void
fdb_free(fdbuffer_t *fdb)
{
        fdb_holes_t *fdh, *fdhp;

        DEBUGF(FDB_D_CREATE, (CE_NOTE, "?fdb_free: addr: %p flags: %x",
            (void *)fdb, fdb->fd_state));

        ASSERT(fdb);
        ASSERT(fdb->fd_iodispatch == 0);

        if (fdb->fd_state & FDB_ZEROHOLE) {
                fdb_zero_holes(fdb);
        }

        for (fdh = fdb->fd_holes; fdh; ) {
                fdhp = fdh;
                fdh = fdh->next_hole;
                kmem_free(fdhp, sizeof (fdb_holes_t));
        }

        if (fdb->fd_parentbp != NULL) {
                switch (fdb->fd_type) {
                case FDB_PAGEIO:
                        pageio_done(fdb->fd_parentbp);
                        break;
                case FDB_VADDR:
                        kmem_free(fdb->fd_parentbp, sizeof (struct buf));
                        break;
                default:
                        cmn_err(CE_CONT, "?fdb_free: Unknown fdb type.");
                        break;
                }
        }

        kmem_cache_free(fdb_cache, fdb);

}

/*
 * The offset should be from the begining of the buffer
 * it has nothing to do with file offset. This fact should be
 * reflected in the caller of this routine.
 */

void
fdb_add_hole(fdbuffer_t *fdb, u_offset_t off, size_t len)
{
        fdb_holes_t *this_hole;

        ASSERT(fdb);
        ASSERT(off < fdb->fd_len);

        DEBUGF(FDB_D_IO, (CE_NOTE, "?fdb_add_hole: off %llx len %lx",
            off, len));

        this_hole = kmem_alloc(sizeof (fdb_holes_t), KM_SLEEP);
        this_hole->off = off;
        this_hole->len = len;

        if (fdb->fd_holes == NULL || off < fdb->fd_holes->off) {
                this_hole->next_hole = fdb->fd_holes;
                fdb->fd_holes = this_hole;
        } else {
                fdb_holes_t *fdhp = fdb->fd_holes;

                while (fdhp->next_hole && off > fdhp->next_hole->off)
                        fdhp = fdhp->next_hole;

                this_hole->next_hole = fdhp->next_hole;
                fdhp->next_hole = this_hole;
        }

        mutex_enter(&fdb->fd_mutex);

        fdb->fd_iocount += len;

        mutex_exit(&fdb->fd_mutex);
}

fdb_holes_t *
fdb_get_holes(fdbuffer_t *fdb)
{
        ASSERT(fdb);

        if (fdb->fd_state & FDB_ZEROHOLE) {
                fdb_zero_holes(fdb);
        }

        return (fdb->fd_holes);
}

/*
 * Note that offsets refer to offsets from the begining of the buffer
 * and as such the memory should be cleared accordingly.
 */

static void
fdb_zero_holes(fdbuffer_t *fdb)
{
        fdb_holes_t *fdh = fdb->fd_holes;
        page_t *pp;

        ASSERT(fdb);

        if (!fdh)
                return;

        switch (fdb->fd_type) {
        case FDB_PAGEIO:
                pp = fdb->fd_pages;
                while (fdh) {
                        fdb_holes_t *pfdh = fdh;
                        size_t l = fdh->len;
                        u_offset_t o = fdh->off;
                        ASSERT(pp);

                        do {
                                int  zerolen;
                                ASSERT(o >= pp->p_offset);

                                /*
                                 * This offset is wrong since
                                 * the offset passed from the pages
                                 * perspective starts at some virtual
                                 * address but the hole is relative
                                 * to the beginning of the fdbuffer.
                                 */
                                if (o >= pp->p_offset + PAGESIZE)
                                        continue;

                                zerolen = min(PAGESIZE, l);

                                ASSERT(zerolen > 0);
                                ASSERT(zerolen <= PAGESIZE);

                                pagezero(pp, ((uintptr_t)o & PAGEOFFSET),
                                    zerolen);

                                l -= zerolen;
                                o += zerolen;

                                if (l == 0)
                                        break;

                        } while (pp = page_list_next(pp));

                        if (!pp)
                                break;

                        fdh = fdh->next_hole;
                        kmem_free(pfdh, sizeof (fdb_holes_t));
                }
                break;
        case FDB_VADDR:
                while (fdh) {
                        fdb_holes_t *pfdh = fdh;

                        bzero(fdb->fd_addr + fdh->off, fdh->len);

                        fdh = fdh->next_hole;
                        kmem_free(pfdh, sizeof (fdb_holes_t));
                }
                break;
        default:
                panic("fdb_zero_holes: Unknown fdb type.");
                break;
        }
}


buf_t *
fdb_iosetup(fdbuffer_t *fdb, u_offset_t off, size_t len, struct vnode *vp,
    int b_flags)
{
        buf_t *bp;

        DEBUGF(FDB_D_IO, (CE_NOTE,
            "?fdb_iosetup: off: %llx len: %lux fdb: len: %lux flags: %x",
            off, len, fdb->fd_len, fdb->fd_state));

        ASSERT(fdb);

        mutex_enter(&fdb->fd_mutex);

        ASSERT(((b_flags & B_READ) && (fdb->fd_state & FDB_READ)) ||
            ((b_flags & B_WRITE) && (fdb->fd_state & FDB_WRITE)));
        /*
         * The fdb can be used either in sync or async mode, if the
         * buffer has not been used it may be used in either mode, but
         * once you have started to use the buf in either mode all
         * subsequent i/o requests must take place the same way.
         */

        ASSERT(((b_flags & B_ASYNC) &&
            ((fdb->fd_state & FDB_ASYNC) || !(fdb->fd_state & FDB_SYNC))) ||
            (!(b_flags & B_ASYNC) &&
            ((fdb->fd_state & FDB_SYNC) || !(fdb->fd_state & FDB_ASYNC))));


        fdb->fd_state |= b_flags & B_ASYNC ? FDB_ASYNC : FDB_SYNC;

        fdb->fd_iodispatch++;

        ASSERT((fdb->fd_state & FDB_ASYNC && fdb->fd_iofunc != NULL) ||
            fdb->fd_state & FDB_SYNC);

        mutex_exit(&fdb->fd_mutex);

        ASSERT((len & (DEV_BSIZE - 1)) == 0);
        ASSERT(off+len <= fdb->fd_len);

        switch (fdb->fd_type) {
        case FDB_PAGEIO:
                if (fdb->fd_parentbp == NULL) {
                        bp = pageio_setup(fdb->fd_pages, len, vp, b_flags);
                        fdb->fd_parentbp = bp;
                }
                break;
        case FDB_VADDR:
                if (fdb->fd_parentbp == NULL) {

                        bp = kmem_alloc(sizeof (buf_t), KM_SLEEP);
                        bioinit(bp);
                        bp->b_error = 0;
                        bp->b_proc = fdb->fd_procp;
                        bp->b_flags = b_flags | B_BUSY | B_PHYS;
                        bp->b_bcount = len;
                        bp->b_un.b_addr = fdb->fd_addr;
                        bp->b_shadow = fdb->fd_shadow;
                        if (fdb->fd_shadow != NULL)
                                bp->b_flags |= B_SHADOW;
                        fdb->fd_parentbp = bp;
                }
                break;
        default:
                panic("fdb_iosetup: Unsupported fdb type.");
                break;
        };

        bp = bioclone(fdb->fd_parentbp, off, len, 0, 0,
            (b_flags & B_ASYNC) ? fdb_iodone : NULL,
            NULL, KM_SLEEP);

        bp->b_forw = (struct buf *)fdb;

        if (b_flags & B_ASYNC)
                bp->b_flags |= B_ASYNC;

        return (bp);
}

size_t
fdb_get_iolen(fdbuffer_t *fdb)
{
        ASSERT(fdb);
        ASSERT(fdb->fd_iodispatch == 0);

        return (fdb->fd_iocount - fdb->fd_resid);
}

void
fdb_ioerrdone(fdbuffer_t *fdb, int error)
{
        ASSERT(fdb);
        ASSERT(fdb->fd_state & FDB_ASYNC);

        DEBUGF(FDB_D_IO, (CE_NOTE,
            "?fdb_ioerrdone: fdb: len: %lux flags: %x error: %d",
            fdb->fd_len, fdb->fd_state, error));

        mutex_enter(&fdb->fd_mutex);

        fdb->fd_err = error;

        if (error)
                fdb->fd_state |= FDB_ERROR;
        else
                fdb->fd_state |= FDB_DONE;

        /*
         * If there is outstanding i/o return wainting for i/o's to complete.
         */
        if (fdb->fd_iodispatch > 0) {
                mutex_exit(&fdb->fd_mutex);
                return;
        }

        mutex_exit(&fdb->fd_mutex);
        fdb->fd_iofunc(fdb, fdb->fd_iargp, NULL);
}

int
fdb_iodone(buf_t *bp)
{
        fdbuffer_t *fdb = (fdbuffer_t *)bp->b_forw;
        int     error, isasync;
        int     icallback;

        ASSERT(fdb);

        DEBUGF(FDB_D_IO, (CE_NOTE,
            "?fdb_iodone: fdb: len: %lux flags: %x error: %d",
            fdb->fd_len, fdb->fd_state, geterror(bp)));

        if (bp->b_flags & B_REMAPPED)
                bp_mapout(bp);

        mutex_enter(&fdb->fd_mutex);

        icallback = fdb->fd_state & FDB_ICALLBACK;
        isasync = fdb->fd_state & FDB_ASYNC;

        ASSERT(fdb->fd_iodispatch > 0);
        fdb->fd_iodispatch--;

        if (error = geterror(bp)) {
                fdb->fd_err = error;
                if (bp->b_resid)
                        fdb->fd_resid += bp->b_resid;
                else
                        fdb->fd_resid += bp->b_bcount;
        }

        fdb->fd_iocount += bp->b_bcount;

        /*
         * ioack collects the total amount of i/o accounted for
         * this includes:
         *
         *      - i/o completed
         *      - i/o attempted but not completed,
         *      - i/o not done due to holes.
         *
         * Once the entire i/o ranges has been accounted for we'll
         * call the async function associated with the fdb.
         *
         */

        if ((fdb->fd_iodispatch == 0) &&
            (fdb->fd_state & (FDB_ERROR|FDB_DONE))) {

                mutex_exit(&fdb->fd_mutex);

                if (isasync || icallback) {
                        fdb->fd_iofunc(fdb, fdb->fd_iargp, bp);
                }

        } else {

                mutex_exit(&fdb->fd_mutex);

                if (icallback) {
                        fdb->fd_iofunc(fdb, fdb->fd_iargp, bp);
                }
        }

        freerbuf(bp);
        return (0);
}