modules/genunix/bio.c

	bio.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * 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 2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <mdb/mdb_modapi.h>
#include <sys/buf.h>
#include <sys/var.h>
#include <vm/page.h>

#include "bio.h"

typedef struct buf_walk {
    uintptr_t bw_hbufbase;      /* Base address of hbuf buckets */
    struct hbuf *bw_hbufs;      /* Snapshot of hbuf buckets */
    size_t bw_nhbufs;       /* Number of hbuf buckets */
    size_t bw_hbufi;        /* Current hbuf index */
    buf_t *bw_bufp;         /* Current buffer */
} buf_walk_t;

int
buf_walk_init(mdb_walk_state_t *wsp)
{
    struct hbuf *hbufs;
    struct var v;

    uintptr_t hbuf_addr;
    size_t nbytes;

    buf_walk_t *bwp;

    if (wsp->walk_addr != NULL) {
        mdb_warn("only global buf walk supported\n");
        return (WALK_ERR);
    }

    if (mdb_readvar(&v, "v") == -1) {
        mdb_warn("failed to read var struct");
        return (WALK_ERR);
    }

    if (mdb_readvar(&hbuf_addr, "hbuf") == -1) {
        mdb_warn("failed to read hbuf pointer");
        return (WALK_ERR);
    }

    nbytes = sizeof (struct hbuf) * v.v_hbuf;
    hbufs = mdb_alloc(nbytes, UM_SLEEP);

    if (mdb_vread(hbufs, nbytes, hbuf_addr) != nbytes) {
        mdb_warn("failed to read hbufs");
        mdb_free(hbufs, nbytes);
        return (WALK_ERR);
    }

    bwp = mdb_alloc(sizeof (buf_walk_t), UM_SLEEP);

    bwp->bw_hbufbase = hbuf_addr;
    bwp->bw_hbufs = hbufs;
    bwp->bw_nhbufs = v.v_hbuf;
    bwp->bw_hbufi = 0;
    bwp->bw_bufp = mdb_alloc(sizeof (buf_t), UM_SLEEP);

    wsp->walk_addr = (uintptr_t)hbufs[0].b_forw;
    wsp->walk_data = bwp;

    return (WALK_NEXT);
}

int
buf_walk_step(mdb_walk_state_t *wsp)
{
    buf_walk_t *bwp = wsp->walk_data;
    uintptr_t addr;

    /*
     * If the next buf_t address we want is NULL or points back at the
     * hbuf itself, advance to the next hash bucket.  When we reach
     * bw_nhbufs, we're done.
     */
    while (wsp->walk_addr == NULL || wsp->walk_addr == (bwp->bw_hbufbase +
        bwp->bw_hbufi * sizeof (struct hbuf))) {

        if (++bwp->bw_hbufi == bwp->bw_nhbufs)
            return (WALK_DONE);

        wsp->walk_addr = (uintptr_t)
            bwp->bw_hbufs[bwp->bw_hbufi].b_forw;
    }

    /*
     * When we have a buf_t address, read the buffer and invoke our
     * walk callback.  We keep the next buf_t address in wsp->walk_addr.
     */
    addr = wsp->walk_addr;
    (void) mdb_vread(bwp->bw_bufp, sizeof (buf_t), addr);
    wsp->walk_addr = (uintptr_t)bwp->bw_bufp->b_forw;

    return (wsp->walk_callback(addr, bwp->bw_bufp, wsp->walk_cbdata));
}

void
buf_walk_fini(mdb_walk_state_t *wsp)
{
    buf_walk_t *bwp = wsp->walk_data;

    mdb_free(bwp->bw_hbufs, sizeof (struct hbuf) * bwp->bw_nhbufs);
    mdb_free(bwp->bw_bufp, sizeof (buf_t));
    mdb_free(bwp, sizeof (buf_walk_t));
}

/*ARGSUSED*/
int
bufpagefind(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
{
    uintptr_t b_addr = addr;
    uintptr_t arg;

    page_t p;
    buf_t b;

    if (argc != 1)
        return (DCMD_USAGE);

    if (argv->a_type == MDB_TYPE_IMMEDIATE)
        arg = (uintptr_t)argv->a_un.a_val;
    else
        arg = (uintptr_t)mdb_strtoull(argv->a_un.a_str);

    if (mdb_vread(&b, sizeof (buf_t), b_addr) == -1)
        return (DCMD_ERR);

    for (addr = (uintptr_t)b.b_pages; addr != NULL;
        addr = (uintptr_t)p.p_next) {

        if (addr == arg) {
            mdb_printf("buf %p has page %p on b_pages list\n",
                b_addr, addr);
            break;
        }

        if (mdb_vread(&p, sizeof (page_t), addr) == -1)
            return (DCMD_ERR);
    }

    return (DCMD_OK);
}