312 lines
8.1 KiB
C
312 lines
8.1 KiB
C
/*
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* Copyright (c) 1992 William F. Jolitz, TeleMuse
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* All rights reserved.
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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 software is a component of "386BSD" developed by
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William F. Jolitz, TeleMuse.
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* 4. Neither the name of the developer nor the name "386BSD"
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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 A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ
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* AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS
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* SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT.
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* THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT
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* NOT MAKE USE THIS WORK.
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*
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* FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
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* BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN
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* REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES
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* (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING
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* JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND
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* LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE
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* ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS
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* OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
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*
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* THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``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 DEVELOPER 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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*/
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/*
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* Changes Copyright (C) 1995, David Greenman & John Dyson; This software may
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* be used, modified, copied, distributed, and sold, in both source and
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* binary form provided that the above copyright and these terms are
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* retained. Under no circumstances is the author responsible for the proper
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* functioning of this software, nor does the author assume any responsibility
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* for damages incurred with its use.
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*
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* $Id: subr_rlist.c,v 1.26 1998/04/15 17:46:25 bde Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/rlist.h>
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#include <vm/vm.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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/*
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* Resource lists.
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*/
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#define RLIST_MIN 128
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static int rlist_count=0;
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static struct rlist *rlfree;
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static struct rlist *rlist_malloc __P((void));
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static __inline void rlist_mfree __P((struct rlist *rl));
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static struct rlist *
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rlist_malloc()
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{
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struct rlist *rl;
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int i;
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while( rlist_count < RLIST_MIN) {
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int s = splhigh();
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rl = (struct rlist *)kmem_alloc(kernel_map, PAGE_SIZE);
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splx(s);
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if( !rl)
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break;
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for(i=0;i<(PAGE_SIZE/(sizeof *rl));i++) {
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rl->rl_next = rlfree;
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rlfree = rl;
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rlist_count++;
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rl++;
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}
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}
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if( (rl = rlfree) == 0 )
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panic("Cannot get an rlist entry");
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--rlist_count;
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rlfree = rl->rl_next;
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return rl;
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}
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static __inline void
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rlist_mfree(rl)
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struct rlist *rl;
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{
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rl->rl_next = rlfree;
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rlfree = rl;
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++rlist_count;
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}
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void
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rlist_free(rlh, start, end)
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struct rlisthdr *rlh;
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u_int start, end;
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{
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struct rlist **rlp = &rlh->rlh_list;
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struct rlist *prev_rlp = NULL, *cur_rlp, *next_rlp = NULL;
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int s;
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s = splhigh();
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while (rlh->rlh_lock & RLH_LOCKED) {
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rlh->rlh_lock |= RLH_DESIRED;
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tsleep(rlh, PSWP, "rlistf", 0);
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}
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rlh->rlh_lock |= RLH_LOCKED;
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splx(s);
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/*
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* Traverse the list looking for an entry after the one we want
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* to insert.
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*/
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cur_rlp = *rlp;
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while (cur_rlp != NULL) {
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if (start < cur_rlp->rl_start)
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break;
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#ifdef DIAGNOSTIC
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if (prev_rlp) {
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if (prev_rlp->rl_end + 1 == cur_rlp->rl_start)
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panic("rlist_free: missed coalesce opportunity");
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if (prev_rlp->rl_end == cur_rlp->rl_start)
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panic("rlist_free: entries overlap");
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if (prev_rlp->rl_end > cur_rlp->rl_start)
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panic("entries out of order");
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}
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#endif
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prev_rlp = cur_rlp;
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cur_rlp = cur_rlp->rl_next;
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}
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if (cur_rlp != NULL) {
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if (end >= cur_rlp->rl_start)
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panic("rlist_free: free end overlaps already freed area");
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if (prev_rlp) {
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if (start <= prev_rlp->rl_end)
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panic("rlist_free: free start overlaps already freed area");
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/*
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* Attempt to append
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*/
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if (prev_rlp->rl_end + 1 == start) {
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prev_rlp->rl_end = end;
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/*
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* Attempt to prepend and coalesce
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*/
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if (end + 1 == cur_rlp->rl_start) {
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prev_rlp->rl_end = cur_rlp->rl_end;
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prev_rlp->rl_next = cur_rlp->rl_next;
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rlist_mfree(cur_rlp);
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}
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goto done;
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}
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}
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/*
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* Attempt to prepend
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*/
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if (end + 1 == cur_rlp->rl_start) {
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cur_rlp->rl_start = start;
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goto done;
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}
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}
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/*
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* Reached the end of the list without finding a larger entry.
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* Append to last entry if there is one and it's adjacent.
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*/
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if (prev_rlp) {
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if (start <= prev_rlp->rl_end)
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panic("rlist_free: free start overlaps already freed area at list tail");
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/*
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* Attempt to append
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*/
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if (prev_rlp->rl_end + 1 == start) {
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prev_rlp->rl_end = end;
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goto done;
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}
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}
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/*
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* Could neither append nor prepend; allocate a new entry.
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*/
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next_rlp = cur_rlp;
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cur_rlp = rlist_malloc();
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cur_rlp->rl_start = start;
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cur_rlp->rl_end = end;
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cur_rlp->rl_next = next_rlp;
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if (prev_rlp) {
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prev_rlp->rl_next = cur_rlp;
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} else {
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/*
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* No previous - this entry is the new list head.
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*/
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*rlp = cur_rlp;
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}
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done:
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rlh->rlh_lock &= ~RLH_LOCKED;
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if (rlh->rlh_lock & RLH_DESIRED) {
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wakeup(rlh);
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rlh->rlh_lock &= ~RLH_DESIRED;
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}
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return;
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}
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/*
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* Obtain a region of desired size from a resource list.
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* If nothing available of that size, return 0. Otherwise,
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* return a value of 1 and set resource start location with
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* "*loc". (Note: loc can be zero if we don't wish the value)
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*/
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int
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rlist_alloc (rlh, size, loc)
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struct rlisthdr *rlh;
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unsigned size, *loc;
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{
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struct rlist **rlp = &rlh->rlh_list;
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register struct rlist *lp;
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int s;
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register struct rlist *olp = 0;
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s = splhigh();
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while (rlh->rlh_lock & RLH_LOCKED) {
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rlh->rlh_lock |= RLH_DESIRED;
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tsleep(rlh, PSWP, "rlistf", 0);
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}
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rlh->rlh_lock |= RLH_LOCKED;
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splx(s);
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/* walk list, allocating first thing that's big enough (first fit) */
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for (; *rlp; rlp = &((*rlp)->rl_next))
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if(size <= (*rlp)->rl_end - (*rlp)->rl_start + 1) {
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/* hand it to the caller */
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if (loc) *loc = (*rlp)->rl_start;
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(*rlp)->rl_start += size;
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/* did we eat this element entirely? */
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if ((*rlp)->rl_start > (*rlp)->rl_end) {
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lp = (*rlp)->rl_next;
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rlist_mfree(*rlp);
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/*
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* if the deleted element was in fromt
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* of the list, adjust *rlp, else don't.
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*/
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if (olp) {
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olp->rl_next = lp;
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} else {
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*rlp = lp;
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}
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}
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rlh->rlh_lock &= ~RLH_LOCKED;
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if (rlh->rlh_lock & RLH_DESIRED) {
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wakeup(rlh);
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rlh->rlh_lock &= ~RLH_DESIRED;
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}
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return (1);
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} else {
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olp = *rlp;
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}
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rlh->rlh_lock &= ~RLH_LOCKED;
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if (rlh->rlh_lock & RLH_DESIRED) {
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wakeup(rlh);
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rlh->rlh_lock &= ~RLH_DESIRED;
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}
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/* nothing in list that's big enough */
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return (0);
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}
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/*
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* Finished with this resource list, reclaim all space and
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* mark it as being empty.
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*/
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void
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rlist_destroy (rlh)
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struct rlisthdr *rlh;
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{
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struct rlist **rlp = &rlh->rlh_list;
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struct rlist *lp, *nlp;
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lp = *rlp;
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*rlp = 0;
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for (; lp; lp = nlp) {
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nlp = lp->rl_next;
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rlist_mfree(lp);
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}
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}
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