66fefd117b
need to understand the locking around that field. Instead of setting B_ERROR, set b_error instead. b_error is 'owned' by whoever completes the I/O request.
338 lines
9.0 KiB
C
338 lines
9.0 KiB
C
/* $NetBSD: subr_bufq.c,v 1.13 2007/07/29 12:15:45 ad Exp $ */
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/* NetBSD: subr_disk.c,v 1.70 2005/08/20 12:00:01 yamt Exp $ */
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/*-
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* Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_bufq.c,v 1.13 2007/07/29 12:15:45 ad Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/bufq.h>
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#include <sys/bufq_impl.h>
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#include <sys/malloc.h>
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#include <sys/sysctl.h>
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BUFQ_DEFINE(dummy, 0, NULL); /* so that bufq_strats won't be empty */
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#define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0)
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/*
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* Create a device buffer queue.
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*/
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int
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bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags)
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{
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__link_set_decl(bufq_strats, const struct bufq_strat);
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const struct bufq_strat *bsp;
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const struct bufq_strat * const *it;
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struct bufq_state *bufq;
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int error = 0;
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KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY);
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switch (flags & BUFQ_SORT_MASK) {
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case BUFQ_SORT_RAWBLOCK:
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case BUFQ_SORT_CYLINDER:
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break;
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case 0:
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/*
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* for strategies which don't care about block numbers.
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* eg. fcfs
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*/
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flags |= BUFQ_SORT_RAWBLOCK;
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break;
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default:
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panic("bufq_alloc: sort out of range");
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}
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/*
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* select strategy.
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* if a strategy specified by flags is found, use it.
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* otherwise, select one with the largest bs_prio.
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*/
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bsp = NULL;
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__link_set_foreach(it, bufq_strats) {
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if ((*it) == &bufq_strat_dummy)
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continue;
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if (strategy != BUFQ_STRAT_ANY &&
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STRAT_MATCH(strategy, (*it))) {
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bsp = *it;
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break;
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}
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if (bsp == NULL || (*it)->bs_prio > bsp->bs_prio)
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bsp = *it;
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}
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if (bsp == NULL) {
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panic("bufq_alloc: no strategy");
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}
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if (strategy != BUFQ_STRAT_ANY && !STRAT_MATCH(strategy, bsp)) {
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if ((flags & BUFQ_EXACT)) {
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error = ENOENT;
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goto out;
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}
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#if defined(DEBUG)
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printf("bufq_alloc: '%s' is not available. using '%s'.\n",
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strategy, bsp->bs_name);
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#endif
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}
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#if defined(BUFQ_DEBUG)
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/* XXX aprint? */
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printf("bufq_alloc: using '%s'\n", bsp->bs_name);
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#endif
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*bufqp = bufq = malloc(sizeof(*bufq), M_DEVBUF, M_WAITOK | M_ZERO);
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bufq->bq_flags = flags;
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bufq->bq_strat = bsp;
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(*bsp->bs_initfn)(bufq);
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out:
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return error;
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}
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void
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bufq_put(struct bufq_state *bufq, struct buf *bp)
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{
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(*bufq->bq_put)(bufq, bp);
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}
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struct buf *
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bufq_get(struct bufq_state *bufq)
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{
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return (*bufq->bq_get)(bufq, 1);
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}
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struct buf *
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bufq_peek(struct bufq_state *bufq)
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{
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return (*bufq->bq_get)(bufq, 0);
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}
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/*
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* Drain a device buffer queue.
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*/
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void
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bufq_drain(struct bufq_state *bufq)
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{
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struct buf *bp;
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while ((bp = BUFQ_GET(bufq)) != NULL) {
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bp->b_error = EIO;
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bp->b_resid = bp->b_bcount;
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biodone(bp);
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}
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}
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/*
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* Destroy a device buffer queue.
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*/
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void
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bufq_free(struct bufq_state *bufq)
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{
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KASSERT(bufq->bq_private != NULL);
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KASSERT(BUFQ_PEEK(bufq) == NULL);
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free(bufq->bq_private, M_DEVBUF);
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free(bufq, M_DEVBUF);
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}
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/*
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* get a strategy identifier of a buffer queue.
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*/
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const char *
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bufq_getstrategyname(struct bufq_state *bufq)
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{
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return bufq->bq_strat->bs_name;
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}
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/*
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* move all requests on a buffer queue to another.
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*/
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void
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bufq_move(struct bufq_state *dst, struct bufq_state *src)
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{
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struct buf *bp;
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while ((bp = BUFQ_GET(src)) != NULL) {
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BUFQ_PUT(dst, bp);
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}
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}
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static int
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docopy(char *buf, size_t *bufoffp, size_t buflen,
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const char *datap, size_t datalen)
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{
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int error = 0;
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if (buf != NULL && datalen > 0) {
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if (*bufoffp + datalen > buflen) {
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goto out;
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}
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error = copyout(datap, buf + *bufoffp, datalen);
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if (error) {
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goto out;
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}
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}
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out:
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if (error == 0) {
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*bufoffp += datalen;
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}
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return error;
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}
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static int
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docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap)
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{
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return docopy(buf, bufoffp, buflen, datap, strlen(datap));
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}
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static int
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docopynul(char *buf, size_t *bufoffp, size_t buflen)
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{
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return docopy(buf, bufoffp, buflen, "", 1);
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}
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/*
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* sysctl function that will print all bufq strategies
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* built in the kernel.
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*/
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static int
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sysctl_kern_bufq_strategies(SYSCTLFN_ARGS)
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{
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__link_set_decl(bufq_strats, const struct bufq_strat);
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const struct bufq_strat * const *bq_strat;
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const char *delim = "";
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size_t off = 0;
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size_t buflen = *oldlenp;
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int error;
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__link_set_foreach(bq_strat, bufq_strats) {
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if ((*bq_strat) == &bufq_strat_dummy) {
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continue;
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}
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error = docopystr(oldp, &off, buflen, delim);
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if (error) {
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goto out;
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}
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error = docopystr(oldp, &off, buflen, (*bq_strat)->bs_name);
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if (error) {
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goto out;
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}
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delim = " ";
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}
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/* NUL terminate */
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error = docopynul(oldp, &off, buflen);
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out:
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*oldlenp = off;
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return error;
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}
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SYSCTL_SETUP(sysctl_kern_bufq_strategies_setup, "sysctl kern.bufq tree setup")
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{
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const struct sysctlnode *node;
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sysctl_createv(clog, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "kern", NULL,
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NULL, 0, NULL, 0,
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CTL_KERN, CTL_EOL);
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node = NULL;
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sysctl_createv(clog, 0, NULL, &node,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "bufq",
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SYSCTL_DESCR("buffer queue subtree"),
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NULL, 0, NULL, 0,
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CTL_KERN, CTL_CREATE, CTL_EOL);
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if (node != NULL) {
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sysctl_createv(clog, 0, NULL, NULL,
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CTLFLAG_PERMANENT,
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CTLTYPE_STRING, "strategies",
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SYSCTL_DESCR("List of bufq strategies present"),
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sysctl_kern_bufq_strategies, 0, NULL, 0,
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CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
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}
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}
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