/* * 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. * */ /* * Changes Copyright (C) 1995, David Greenman & John Dyson; This software may * be used, modified, copied, distributed, and sold, in both source and * binary form provided that the above copyright and these terms are * retained. Under no circumstances is the author responsible for the proper * functioning of this software, nor does the author assume any responsibility * for damages incurred with its use. * * $Id: subr_rlist.c,v 1.18 1996/10/12 21:35:25 dyson Exp $ */ #include #include #include #include #include #include #include #include #include /* * Resource lists. */ #define RLIST_MIN 128 static int rlist_count=0; static struct rlist *rlfree; static struct rlist *rlist_malloc __P((void)); static struct rlist * rlist_malloc() { struct rlist *rl; int i; while( rlist_count < RLIST_MIN) { int s = splhigh(); rl = (struct rlist *)kmem_alloc(kernel_map, PAGE_SIZE); splx(s); if( !rl) break; for(i=0;i<(PAGE_SIZE/(sizeof *rl));i++) { rl->rl_next = rlfree; rlfree = rl; rlist_count++; rl++; } } if( (rl = rlfree) == 0 ) panic("Cannot get an rlist entry"); --rlist_count; rlfree = rl->rl_next; return rl; } inline static void rlist_mfree( struct rlist *rl) { rl->rl_next = rlfree; rlfree = rl; ++rlist_count; } void rlist_free(rlh, start, end) struct rlisthdr *rlh; u_int start, end; { struct rlist **rlp = &rlh->rlh_list; struct rlist *prev_rlp = NULL, *cur_rlp = *rlp, *next_rlp = NULL; int s; s = splhigh(); while (rlh->rlh_lock & RLH_LOCKED) { rlh->rlh_lock |= RLH_DESIRED; tsleep(rlh, PSWP, "rlistf", 0); } rlh->rlh_lock |= RLH_LOCKED; splx(s); /* * Traverse the list looking for an entry after the one we want * to insert. */ while (cur_rlp != NULL) { if (start < cur_rlp->rl_start) break; #ifdef DIAGNOSTIC if (prev_rlp) { if (prev_rlp->rl_end + 1 == cur_rlp->rl_start) panic("rlist_free: missed coalesce opportunity"); if (prev_rlp->rl_end == cur_rlp->rl_start) panic("rlist_free: entries overlap"); if (prev_rlp->rl_end > cur_rlp->rl_start) panic("entries out of order"); } #endif prev_rlp = cur_rlp; cur_rlp = cur_rlp->rl_next; } if (cur_rlp != NULL) { if (end >= cur_rlp->rl_start) panic("rlist_free: free end overlaps already freed area"); if (prev_rlp) { if (start <= prev_rlp->rl_end) panic("rlist_free: free start overlaps already freed area"); /* * Attempt to append */ if (prev_rlp->rl_end + 1 == start) { prev_rlp->rl_end = end; /* * Attempt to prepend and coalesce */ if (end + 1 == cur_rlp->rl_start) { prev_rlp->rl_end = cur_rlp->rl_end; prev_rlp->rl_next = cur_rlp->rl_next; rlist_mfree(cur_rlp); } goto done; } } /* * Attempt to prepend */ if (end + 1 == cur_rlp->rl_start) { cur_rlp->rl_start = start; goto done; } } /* * Reached the end of the list without finding a larger entry. * Append to last entry if there is one and it's adjacent. */ if (prev_rlp) { if (start <= prev_rlp->rl_end) panic("rlist_free: free start overlaps already freed area at list tail"); /* * Attempt to append */ if (prev_rlp->rl_end + 1 == start) { prev_rlp->rl_end = end; goto done; } } /* * Could neither append nor prepend; allocate a new entry. */ next_rlp = cur_rlp; cur_rlp = rlist_malloc(); cur_rlp->rl_start = start; cur_rlp->rl_end = end; cur_rlp->rl_next = next_rlp; if (prev_rlp) { prev_rlp->rl_next = cur_rlp; } else { /* * No previous - this entry is the new list head. */ *rlp = cur_rlp; } done: rlh->rlh_lock &= ~RLH_LOCKED; if (rlh->rlh_lock & RLH_DESIRED) { wakeup(rlh); rlh->rlh_lock &= ~RLH_DESIRED; } return; } /* * 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 (rlh, size, loc) struct rlisthdr *rlh; unsigned size, *loc; { struct rlist **rlp = &rlh->rlh_list; register struct rlist *lp; int s; register struct rlist *olp = 0; s = splhigh(); while (rlh->rlh_lock & RLH_LOCKED) { rlh->rlh_lock |= RLH_DESIRED; tsleep(rlh, PSWP, "rlistf", 0); } rlh->rlh_lock |= RLH_LOCKED; splx(s); /* 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; rlist_mfree(*rlp); /* * if the deleted element was in fromt * of the list, adjust *rlp, else don't. */ if (olp) { olp->rl_next = lp; } else { *rlp = lp; } } rlh->rlh_lock &= ~RLH_LOCKED; if (rlh->rlh_lock & RLH_DESIRED) { wakeup(rlh); rlh->rlh_lock &= ~RLH_DESIRED; } return (1); } else { olp = *rlp; } rlh->rlh_lock &= ~RLH_LOCKED; if (rlh->rlh_lock & RLH_DESIRED) { wakeup(rlh); rlh->rlh_lock &= ~RLH_DESIRED; } /* nothing in list that's big enough */ return (0); } /* * Finished with this resource list, reclaim all space and * mark it as being empty. */ void rlist_destroy (rlh) struct rlisthdr *rlh; { struct rlist **rlp = &rlh->rlh_list; struct rlist *lp, *nlp; lp = *rlp; *rlp = 0; for (; lp; lp = nlp) { nlp = lp->rl_next; rlist_mfree(lp); } }