From 89b6e8a2953a21568e5236956bf0747fd09a21be Mon Sep 17 00:00:00 2001 From: "William F. Jolitz" Date: Wed, 11 Mar 1992 22:19:16 -0800 Subject: [PATCH] 386BSD 0.1 development Work on file usr/src/sys.386bsd/kern/subr_rlist.c Co-Authored-By: Lynne Greer Jolitz Synthesized-from: 386BSD-0.1 --- usr/src/sys.386bsd/kern/subr_rlist.c | 191 +++++++++++++++++++++++++++ 1 file changed, 191 insertions(+) create mode 100644 usr/src/sys.386bsd/kern/subr_rlist.c diff --git a/usr/src/sys.386bsd/kern/subr_rlist.c b/usr/src/sys.386bsd/kern/subr_rlist.c new file mode 100644 index 0000000000..3adf5a8195 --- /dev/null +++ b/usr/src/sys.386bsd/kern/subr_rlist.c @@ -0,0 +1,191 @@ +/* + * Copyright (c) 1992 William F. Jolitz, TeleMuse + * All rights reserved. + * + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This software is a component of "386BSD" developed by + William F. Jolitz, TeleMuse. + * 4. Neither the name of the developer nor the name "386BSD" + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ + * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS + * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. + * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT + * NOT MAKE USE THIS WORK. + * + * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED + * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN + * REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES + * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING + * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND + * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE + * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS + * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992. + * + * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``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 DEVELOPER 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. + * + */ +static char rcsid[] = "$Header: /usr/bill/working/sys/kern/RCS/subr_rlist.c,v 1.2 92/01/21 21:29:31 william Exp $"; + +#include "sys/param.h" +#include "sys/cdefs.h" +#include "sys/malloc.h" +#include "rlist.h" + +/* + * Resource lists. + */ + +/* + * Add space to a resource list. Used to either + * initialize a list or return free space to it. + */ +rlist_free (rlp, start, end) +register struct rlist **rlp; unsigned start, end; { + struct rlist *head; + + head = *rlp; + +loop: + /* if nothing here, insert (tail of list) */ + if (*rlp == 0) { + *rlp = (struct rlist *)malloc(sizeof(**rlp), M_TEMP, M_NOWAIT); + (*rlp)->rl_start = start; + (*rlp)->rl_end = end; + (*rlp)->rl_next = 0; + return; + } + + /* if new region overlaps something currently present, panic */ + if (start >= (*rlp)->rl_start && start <= (*rlp)->rl_end) { + printf("Frag %d:%d, ent %d:%d ", start, end, + (*rlp)->rl_start, (*rlp)->rl_end); + panic("overlapping front rlist_free: freed twice?"); + } + if (end >= (*rlp)->rl_start && end <= (*rlp)->rl_end) { + printf("Frag %d:%d, ent %d:%d ", start, end, + (*rlp)->rl_start, (*rlp)->rl_end); + panic("overlapping tail rlist_free: freed twice?"); + } + + /* are we adjacent to this element? (in front) */ + if (end+1 == (*rlp)->rl_start) { + /* coalesce */ + (*rlp)->rl_start = start; + goto scan; + } + + /* are we before this element? */ + if (end < (*rlp)->rl_start) { + register struct rlist *nlp; + + nlp = (struct rlist *)malloc(sizeof(*nlp), M_TEMP, M_NOWAIT); + nlp->rl_start = start; + nlp->rl_end = end; + nlp->rl_next = *rlp; + *rlp = nlp; + return; + } + + /* are we adjacent to this element? (at tail) */ + if ((*rlp)->rl_end + 1 == start) { + /* coalesce */ + (*rlp)->rl_end = end; + goto scan; + } + + /* are we after this element */ + if (start > (*rlp)->rl_end) { + rlp = &((*rlp)->rl_next); + goto loop; + } else + panic("rlist_free: can't happen"); + +scan: + /* can we coalesce list now that we've filled a void? */ + { + register struct rlist *lp, *lpn; + + for (lp = head; lp->rl_next ;) { + lpn = lp->rl_next; + + /* coalesce ? */ + if (lp->rl_end + 1 == lpn->rl_start) { + lp->rl_end = lpn->rl_end; + lp->rl_next = lpn->rl_next; + free(lpn, M_TEMP); + } else + lp = lp->rl_next; + } + } +} + +/* + * Obtain a region of desired size from a resource list. + * If nothing available of that size, return 0. Otherwise, + * return a value of 1 and set resource start location with + * "*loc". (Note: loc can be zero if we don't wish the value) + */ +int rlist_alloc (rlp, size, loc) +struct rlist **rlp; unsigned size, *loc; { + register struct rlist *lp; + + + /* walk list, allocating first thing that's big enough (first fit) */ + for (; *rlp; rlp = &((*rlp)->rl_next)) + if(size <= (*rlp)->rl_end - (*rlp)->rl_start + 1) { + + /* hand it to the caller */ + if (loc) *loc = (*rlp)->rl_start; + (*rlp)->rl_start += size; + + /* did we eat this element entirely? */ + if ((*rlp)->rl_start > (*rlp)->rl_end) { + lp = (*rlp)->rl_next; + free (*rlp, M_TEMP); + *rlp = lp; + } + + return (1); + } + + /* nothing in list that's big enough */ + return (0); +} + +/* + * Finished with this resource list, reclaim all space and + * mark it as being empty. + */ +rlist_destroy (rlp) +struct rlist **rlp; { + struct rlist *lp, *nlp; + + lp = *rlp; + *rlp = 0; + for (; lp; lp = nlp) { + nlp = lp->rl_next; + free (lp, M_TEMP); + } +} -- 2.20.1