NetBSD-5.0.2/sys/kern/subr_bufq.c
/* $NetBSD: subr_bufq.c,v 1.15 2008/04/30 12:09:02 reinoud Exp $ */
/* NetBSD: subr_disk.c,v 1.70 2005/08/20 12:00:01 yamt Exp $ */
/*-
* Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_bufq.c,v 1.15 2008/04/30 12:09:02 reinoud Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/bufq.h>
#include <sys/bufq_impl.h>
#include <sys/malloc.h>
#include <sys/sysctl.h>
BUFQ_DEFINE(dummy, 0, NULL); /* so that bufq_strats won't be empty */
#define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0)
/*
* Create a device buffer queue.
*/
int
bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags)
{
__link_set_decl(bufq_strats, const struct bufq_strat);
const struct bufq_strat *bsp;
const struct bufq_strat * const *it;
struct bufq_state *bufq;
int error = 0;
KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY);
switch (flags & BUFQ_SORT_MASK) {
case BUFQ_SORT_RAWBLOCK:
case BUFQ_SORT_CYLINDER:
break;
case 0:
/*
* for strategies which don't care about block numbers.
* eg. fcfs
*/
flags |= BUFQ_SORT_RAWBLOCK;
break;
default:
panic("bufq_alloc: sort out of range");
}
/*
* select strategy.
* if a strategy specified by flags is found, use it.
* otherwise, select one with the largest bs_prio.
*/
bsp = NULL;
__link_set_foreach(it, bufq_strats) {
if ((*it) == &bufq_strat_dummy)
continue;
if (strategy != BUFQ_STRAT_ANY &&
STRAT_MATCH(strategy, (*it))) {
bsp = *it;
break;
}
if (bsp == NULL || (*it)->bs_prio > bsp->bs_prio)
bsp = *it;
}
if (bsp == NULL) {
panic("bufq_alloc: no strategy");
}
if (strategy != BUFQ_STRAT_ANY && !STRAT_MATCH(strategy, bsp)) {
if ((flags & BUFQ_EXACT)) {
error = ENOENT;
goto out;
}
#if defined(DEBUG)
printf("bufq_alloc: '%s' is not available. using '%s'.\n",
strategy, bsp->bs_name);
#endif
}
#if defined(BUFQ_DEBUG)
/* XXX aprint? */
printf("bufq_alloc: using '%s'\n", bsp->bs_name);
#endif
*bufqp = bufq = malloc(sizeof(*bufq), M_DEVBUF, M_WAITOK | M_ZERO);
bufq->bq_flags = flags;
bufq->bq_strat = bsp;
(*bsp->bs_initfn)(bufq);
out:
return error;
}
void
bufq_put(struct bufq_state *bufq, struct buf *bp)
{
(*bufq->bq_put)(bufq, bp);
}
struct buf *
bufq_get(struct bufq_state *bufq)
{
return (*bufq->bq_get)(bufq, 1);
}
struct buf *
bufq_peek(struct bufq_state *bufq)
{
return (*bufq->bq_get)(bufq, 0);
}
struct buf *
bufq_cancel(struct bufq_state *bufq, struct buf *bp)
{
return (*bufq->bq_cancel)(bufq, bp);
}
/*
* Drain a device buffer queue.
*/
void
bufq_drain(struct bufq_state *bufq)
{
struct buf *bp;
while ((bp = BUFQ_GET(bufq)) != NULL) {
bp->b_error = EIO;
bp->b_resid = bp->b_bcount;
biodone(bp);
}
}
/*
* Destroy a device buffer queue.
*/
void
bufq_free(struct bufq_state *bufq)
{
KASSERT(bufq->bq_private != NULL);
KASSERT(BUFQ_PEEK(bufq) == NULL);
free(bufq->bq_private, M_DEVBUF);
free(bufq, M_DEVBUF);
}
/*
* get a strategy identifier of a buffer queue.
*/
const char *
bufq_getstrategyname(struct bufq_state *bufq)
{
return bufq->bq_strat->bs_name;
}
/*
* move all requests on a buffer queue to another.
*/
void
bufq_move(struct bufq_state *dst, struct bufq_state *src)
{
struct buf *bp;
while ((bp = BUFQ_GET(src)) != NULL) {
BUFQ_PUT(dst, bp);
}
}
static int
docopy(char *buf, size_t *bufoffp, size_t buflen,
const char *datap, size_t datalen)
{
int error = 0;
if (buf != NULL && datalen > 0) {
if (*bufoffp + datalen > buflen) {
goto out;
}
error = copyout(datap, buf + *bufoffp, datalen);
if (error) {
goto out;
}
}
out:
if (error == 0) {
*bufoffp += datalen;
}
return error;
}
static int
docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap)
{
return docopy(buf, bufoffp, buflen, datap, strlen(datap));
}
static int
docopynul(char *buf, size_t *bufoffp, size_t buflen)
{
return docopy(buf, bufoffp, buflen, "", 1);
}
/*
* sysctl function that will print all bufq strategies
* built in the kernel.
*/
static int
sysctl_kern_bufq_strategies(SYSCTLFN_ARGS)
{
__link_set_decl(bufq_strats, const struct bufq_strat);
const struct bufq_strat * const *bq_strat;
const char *delim = "";
size_t off = 0;
size_t buflen = *oldlenp;
int error;
__link_set_foreach(bq_strat, bufq_strats) {
if ((*bq_strat) == &bufq_strat_dummy) {
continue;
}
error = docopystr(oldp, &off, buflen, delim);
if (error) {
goto out;
}
error = docopystr(oldp, &off, buflen, (*bq_strat)->bs_name);
if (error) {
goto out;
}
delim = " ";
}
/* NUL terminate */
error = docopynul(oldp, &off, buflen);
out:
*oldlenp = off;
return error;
}
SYSCTL_SETUP(sysctl_kern_bufq_strategies_setup, "sysctl kern.bufq tree setup")
{
const struct sysctlnode *node;
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "kern", NULL,
NULL, 0, NULL, 0,
CTL_KERN, CTL_EOL);
node = NULL;
sysctl_createv(clog, 0, NULL, &node,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "bufq",
SYSCTL_DESCR("buffer queue subtree"),
NULL, 0, NULL, 0,
CTL_KERN, CTL_CREATE, CTL_EOL);
if (node != NULL) {
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRING, "strategies",
SYSCTL_DESCR("List of bufq strategies present"),
sysctl_kern_bufq_strategies, 0, NULL, 0,
CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
}
}