ns/sdbc/safestore.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <sys/ksynch.h>
#include <sys/kmem.h>
#include <sys/sdt.h>

#include <sys/varargs.h>
#include <sys/unistat/spcs_s.h>

#include "safestore.h"
#include "safestore_impl.h"
#include "sd_trace.h"

typedef struct safestore_modules_s {
    struct safestore_modules_s *ssm_next;
    safestore_ops_t *ssm_module;
} safestore_modules_t;

safestore_modules_t *ss_modules;
kmutex_t safestore_mutex;
int ss_initialized;

/* the safestore module init/deinit functions */

void ss_ram_init();
void ss_ram_deinit();

/* CSTYLED */
/**#
 * initialize the safestore subsystem and all safestore
 * modules by calling all safestore modules' initialization functions
 *
 * NOTE: This function must be called with the _sdbc_config_lock held
 *
 * @param none
 * @return void
 *
 */
void
sst_init()
{
    /*
     * initialize the ss modules we know about
     * this results in calls to sst_register_mod()
     */
    if (ss_initialized != SS_INITTED) {
        mutex_init(&safestore_mutex, NULL, MUTEX_DRIVER, NULL);
        ss_ram_init();
        ss_initialized = SS_INITTED;
    }

}

/* CSTYLED */
/**#
 * deinitialize the safestore subsystem and all safestore modules
 * by calling all safestore modules' deinitialization functions
 *
 * NOTE: This function must be called with the _sdbc_config_lock held
 *
 * @param none
 * @return void
 *
 */
void
sst_deinit()
{
    if (ss_initialized == SS_INITTED) {
        ss_ram_deinit();
        mutex_destroy(&safestore_mutex);
        ss_initialized = 0;
    }
}

/* BEGIN CSTYLED */
/**#
 * called by a safestore module to register its ops table
 * for use by clients
 *
 * @param ss_ops structure of safestore functions
 * @return void
 *
 * @see safestore_ops_t{}
 */
void
sst_register_mod(safestore_ops_t *ss_ops) /* END CSTYLED */
{
    safestore_modules_t *new;

    new = kmem_alloc(sizeof (*new), KM_SLEEP);

    mutex_enter(&safestore_mutex);
    new->ssm_module = ss_ops;
    new->ssm_next = ss_modules;

    ss_modules = new;
    mutex_exit(&safestore_mutex);
}

/* BEGIN CSTYLED */
/**#
 * called by a safestore module to unregister its ops table
 * @param ss_ops structure of safestore functions
 *
 * @return void
 *
 * @see safestore_ops_t{}
 */
void
sst_unregister_mod(safestore_ops_t *ss_ops) /* END CSTYLED */
{
    safestore_modules_t *ssm, *prev;
    int found = 0;

    mutex_enter(&safestore_mutex);
    prev = NULL;
    for (ssm = ss_modules; ssm; prev = ssm, ssm = ssm->ssm_next) {
        if (ssm->ssm_module == ss_ops) {
            if (!prev)
                ss_modules = ssm->ssm_next;
            else
                prev->ssm_next = ssm->ssm_next;

            kmem_free(ssm, sizeof (safestore_modules_t));
            ++found;
            break;
        }
    }
    mutex_exit(&safestore_mutex);

    if (!found)
        cmn_err(CE_WARN, "ss(sst_unregister_mod) "
                "ss module %p not found", (void *)ss_ops);
}

/* BEGIN CSTYLED */
/**#
 * open a safestore module for use by a client
 * @param ss_type  specifies a valid media type and transport type.
 *                 the first module found that supports these reqested type
 *                 is used. may contain more than one media type or transport
 *                 type if client has no preference among several types.
 *                 more than one ss_type may be specified in the call if
 *                 client has an ordered preference.
 *
 * @return safestore_ops_t *  pointer to a valid safestore ops structure
 *                if the request is satisfied.
 *         NULL otherwise
 *
 * @see safestore_ops_t{}
 * @see SS_M_RAM
 * @see SS_M_NV_SINGLENODE
 * @see SS_M_NV_DUALNODE_NOMIRROR
 * @see SS_M_NV_DUALNODE_MIRROR
 * @see SS_T_STE
 * @see SS_T_RPC
 * @see SS_T_NONE
 */
safestore_ops_t *
sst_open(uint_t ss_type, ...) /* END CSTYLED */
{
    va_list ap;
    uint_t ssop_type;
    safestore_modules_t *ssm;

    if ((ss_modules == NULL) || !ss_type)
        return (NULL);

    va_start(ap, ss_type);
    mutex_enter(&safestore_mutex);
    do {
        for (ssm = ss_modules; ssm; ssm = ssm->ssm_next) {
            ssop_type = ssm->ssm_module->ssop_type;
            if ((ssop_type &  SS_MEDIA_MASK) & ss_type)
                if ((ssop_type &  SS_TRANSPORT_MASK) & ss_type) {
                    va_end(ap);
                    mutex_exit(&safestore_mutex);
                    return (ssm->ssm_module);
                }
        }
    } while ((ss_type = va_arg(ap, uint_t)) != 0);
    mutex_exit(&safestore_mutex);

    va_end(ap);
    return (NULL);
}

/* BEGIN CSTYLED */
/**#
 * close a safestore module. called when client no longer wishes to use
 * a safestore module
 *
 * @param ssp  points to a safestore_ops_t obtained from a previous call
 *             to sst_open()
 *
 * @return SS_OK if successful
 *         SS_ERR otherwise
 */
/*ARGSUSED*/
int
sst_close(safestore_ops_t *ssp) /* END CSTYLED */
{
    return (SS_OK);
}


/*
 * _sdbc_writeq_configure - configure the given writeq
 * Allocate the lock and sv we need to maintain waiters
 *
 */
int
_sdbc_writeq_configure(_sd_writeq_t *wrq)
{
    int i;

    wrq->wq_inq = 0;
    mutex_init(&wrq->wq_qlock, NULL, MUTEX_DRIVER, NULL);
    wrq->wq_qtop = NULL;
    wrq->wq_slp_top = 0;
    wrq->wq_slp_index = 0;
    wrq->wq_slp_inq = 0;

    for (i = 0; i < SD_WR_SLP_Q_MAX; i++) {
        wrq->wq_slp[i].slp_wqneed = 0;
        cv_init(&wrq->wq_slp[i].slp_wqcv, NULL, CV_DRIVER, NULL);
    }

    return (0);
}

/*
 * _sdbc_writeq_deconfigure - deconfigure the given writeq
 * Deallocate the lock and sv if present.
 *
 */
void
_sdbc_writeq_deconfigure(_sd_writeq_t *wrq)
{
    int i;

    if (wrq) {
        mutex_destroy(&wrq->wq_qlock);
        for (i = 0; i < SD_WR_SLP_Q_MAX; i++) {
            cv_destroy(&wrq->wq_slp[i].slp_wqcv);
        }
        wrq->wq_inq = 0;
        wrq->wq_qtop = NULL;
    }

}


int _sd_wblk_sync = 1;

ss_wr_cctl_t *
ss_alloc_write(int need, int *stall, _sd_writeq_t *q)
{
    ss_wr_cctl_t *wctl;
    ss_wr_cctl_t *ret;
    int i;
    int aged = 0;

    if (_sd_wblk_sync && (q->wq_inq == 0))
        return (NULL); /* do sync write if queue empty */

    SDTRACE(ST_ENTER|SDF_WR_ALLOC, SDT_INV_CD, need,
        SDT_INV_BL, q->wq_inq, _SD_NO_NET);

    if (need <= 0) {
        cmn_err(CE_WARN, "ss_alloc_write: bogus need value! %d", need);
        return (NULL);
    }

    mutex_enter(&(q->wq_qlock));
retry_wr_get:
    if (q->wq_inq < need) {
        if (!_sd_wblk_sync) {
            unsigned stime;
            stime = nsc_usec();

            /*
             * Try to keep requests ordered so large requests
             * are not starved.  We can queue 255 write requests,
             * After That go into write-through.
             */
            if (q->wq_slp_inq < SD_WR_SLP_Q_MAX) {
                q->wq_slp_inq++;
                /* give preference to aged requests */
                if (aged) {
                    WQ_SVWAIT_TOP(q, need);
                } else {
                    WQ_SVWAIT_BOTTOM(q, need);
                }
                aged++;
            } else {
                mutex_exit(&(q->wq_qlock));
                return (NULL);
            }

            SDTRACE(ST_INFO|SDF_WR_ALLOC,
                SDT_INV_CD, need, SDT_INV_BL, q->wq_inq,
                (nsc_usec()-stime));
            (void) (*stall)++;
            goto retry_wr_get;
        }
        ret = NULL;
    } else {
get_wctl:
        wctl = q->wq_qtop;
        ret = wctl;
        DTRACE_PROBE1(alloc_write,
            ss_wr_cctl_t *, wctl);
        for (i = 1; i < need; ++i) {
            wctl = wctl->wc_next;
            DTRACE_PROBE1(alloc_write_cont,
                ss_wr_cctl_t *, wctl);
        }

        q->wq_qtop = wctl->wc_next;
        wctl->wc_next = NULL;
        q->wq_inq -= need;
    }
    mutex_exit(&(q->wq_qlock));

    SDTRACE(ST_EXIT|SDF_WR_ALLOC, SDT_INV_CD, need,
        SDT_INV_BL, q->wq_inq, _SD_NO_NET);
    return (ret);
}

/*
 * ss_release_write - put a write block back in the writeq.
 *
 * ARGUMENTS:
 *  wctl    - Write control block to be release.
 *      q       - write q to put the wctl
 *
 * RETURNS:     NONE
 */

void
ss_release_write(ss_wr_cctl_t *wctl, _sd_writeq_t *q)
{

    SDTRACE(ST_ENTER|SDF_WR_FREE, SDT_INV_CD, 0, SDT_INV_BL, q->wq_inq,
        _SD_NO_NET);

    DTRACE_PROBE1(release_write,
                ss_wr_cctl_t *, wctl);

#if defined(_SD_DEBUG)
    if (wctl->wc_gl_info->sci_dirty) {
        SDALERT(SDF_WR_FREE, wctl->wc_gl_info->sci_cd,
            0, wctl->wc_gl_info->sci_fpos,
            wctl->wc_gl_info->sci_dirty, 0);
    }
#endif
    mutex_enter(&q->wq_qlock);

    wctl->wc_next = q->wq_qtop;
    q->wq_qtop = wctl;
    q->wq_inq++;
    if (WQ_NEED_SIG(q)) {
        q->wq_slp_inq--;
        WQ_SVSIG(q);
    }
    mutex_exit(&q->wq_qlock);
    SDTRACE(ST_EXIT|SDF_WR_FREE, SDT_INV_CD, 0, SDT_INV_BL, q->wq_inq,
        _SD_NO_NET);
}