adapters/mpt_sas/mptsas_hash.c

/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2014 Joyent, Inc.  All rights reserved.
 */

#include <sys/scsi/adapters/mpt_sas/mptsas_hash.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/kmem.h>
#include <sys/list.h>
#include <sys/ddi.h>

#ifdef lint
extern refhash_link_t *obj_to_link(refhash_t *, void *);
extern void *link_to_obj(refhash_t *, refhash_link_t *);
extern void *obj_to_tag(refhash_t *, void *);
#else
#define obj_to_link(_h, _o) \
    ((refhash_link_t *)(((char *)(_o)) + (_h)->rh_link_off))
#define link_to_obj(_h, _l) \
    ((void *)(((char *)(_l)) - (_h)->rh_link_off))
#define obj_to_tag(_h, _o)  \
    ((void *)(((char *)(_o)) + (_h)->rh_tag_off))
#endif

refhash_t *
refhash_create(uint_t bucket_count, refhash_hash_f hash,
    refhash_cmp_f cmp, refhash_dtor_f dtor, size_t obj_size, size_t link_off,
    size_t tag_off, int km_flags)
{
    refhash_t *hp;
    uint_t i;

    hp = kmem_alloc(sizeof (refhash_t), km_flags);
    if (hp == NULL)
        return (NULL);
    hp->rh_buckets = kmem_zalloc(bucket_count * sizeof (list_t), km_flags);
    if (hp->rh_buckets == NULL) {
        kmem_free(hp, sizeof (refhash_t));
        return (NULL);
    }
    hp->rh_bucket_count = bucket_count;

    for (i = 0; i < bucket_count; i++) {
        list_create(&hp->rh_buckets[i], sizeof (refhash_link_t),
            offsetof(refhash_link_t, rhl_chain_link));
    }
    list_create(&hp->rh_objs, sizeof (refhash_link_t),
        offsetof(refhash_link_t, rhl_global_link));

    hp->rh_obj_size = obj_size;
    hp->rh_link_off = link_off;
    hp->rh_tag_off = tag_off;
    hp->rh_hash = hash;
    hp->rh_cmp = cmp;
    hp->rh_dtor = dtor;

    return (hp);
}

void
refhash_destroy(refhash_t *hp)
{
    ASSERT(list_is_empty(&hp->rh_objs));

    kmem_free(hp->rh_buckets, hp->rh_bucket_count * sizeof (list_t));
    kmem_free(hp, sizeof (refhash_t));
}

void
refhash_insert(refhash_t *hp, void *op)
{
    uint_t bucket;
    refhash_link_t *lp = obj_to_link(hp, op);

    bucket = hp->rh_hash(obj_to_tag(hp, op)) % hp->rh_bucket_count;
    list_link_init(&lp->rhl_chain_link);
    list_link_init(&lp->rhl_global_link);
    lp->rhl_flags = 0;
    lp->rhl_refcnt = 0;
    list_insert_tail(&hp->rh_buckets[bucket], lp);
    list_insert_tail(&hp->rh_objs, lp);
}

static void
refhash_delete(refhash_t *hp, void *op)
{
    refhash_link_t *lp = obj_to_link(hp, op);
    uint_t bucket;

    bucket = hp->rh_hash(obj_to_tag(hp, op)) % hp->rh_bucket_count;
    list_remove(&hp->rh_buckets[bucket], lp);
    list_remove(&hp->rh_objs, lp);
    hp->rh_dtor(op);
}

void
refhash_remove(refhash_t *hp, void *op)
{
    refhash_link_t *lp = obj_to_link(hp, op);

    if (lp->rhl_refcnt > 0) {
        lp->rhl_flags |= RHL_F_DEAD;
    } else {
        refhash_delete(hp, op);
    }
}

void *
refhash_lookup(refhash_t *hp, const void *tp)
{
    uint_t bucket;
    refhash_link_t *lp;
    void *op;

    bucket = hp->rh_hash(tp) % hp->rh_bucket_count;
    for (lp = list_head(&hp->rh_buckets[bucket]); lp != NULL;
        lp = list_next(&hp->rh_buckets[bucket], lp)) {
        op = link_to_obj(hp, lp);
        if (hp->rh_cmp(obj_to_tag(hp, op), tp) == 0 &&
            !(lp->rhl_flags & RHL_F_DEAD)) {
            return (op);
        }
    }

    return (NULL);
}

void *
refhash_linear_search(refhash_t *hp, refhash_eval_f eval, void *arg)
{
    void *op;
    refhash_link_t *lp;

    for (lp = list_head(&hp->rh_objs); lp != NULL;
        lp = list_next(&hp->rh_objs, lp)) {
        op = link_to_obj(hp, lp);
        if (eval(op, arg) == 0)
            return (op);
    }

    return (NULL);
}

void
refhash_hold(refhash_t *hp, void *op)
{
    refhash_link_t *lp = obj_to_link(hp, op);

    ++lp->rhl_refcnt;
}

void
refhash_rele(refhash_t *hp, void *op)
{
    refhash_link_t *lp = obj_to_link(hp, op);

    ASSERT(lp->rhl_refcnt > 0);

    if (--lp->rhl_refcnt == 0 && (lp->rhl_flags & RHL_F_DEAD))
        refhash_remove(hp, op);
}

void *
refhash_first(refhash_t *hp)
{
    refhash_link_t *lp;

    lp = list_head(&hp->rh_objs);
    if (lp == NULL)
        return (NULL);

    ++lp->rhl_refcnt;

    return (link_to_obj(hp, lp));
}

void *
refhash_next(refhash_t *hp, void *op)
{
    refhash_link_t *lp;

    lp = obj_to_link(hp, op);
    while ((lp = list_next(&hp->rh_objs, lp)) != NULL) {
        if (!(lp->rhl_flags & RHL_F_DEAD))
            break;
    }

    refhash_rele(hp, op);
    if (lp == NULL)
        return (NULL);

    ++lp->rhl_refcnt;

    return (link_to_obj(hp, lp));
}

boolean_t
refhash_obj_valid(refhash_t *hp, const void *op)
{
    /* LINTED - E_ARG_INCOMPATIBLE_WITH_ARG_L */
    const refhash_link_t *lp = obj_to_link(hp, op);

    return ((lp->rhl_flags & RHL_F_DEAD) != 0);
}