1033 lines
27 KiB
C
1033 lines
27 KiB
C
/* $NetBSD: subr_extent.c,v 1.12 1998/06/06 02:25:47 thorpej Exp $ */
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/*-
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* Copyright (c) 1996, 1998 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 and Matthias Drochner.
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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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* General purpose extent manager.
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*/
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#ifdef _KERNEL
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#include <sys/param.h>
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#include <sys/extent.h>
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#include <sys/malloc.h>
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#include <sys/time.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/lock.h>
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#else
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/*
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* user-land definitions, so it can fit into a testing harness.
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*/
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#include <sys/param.h>
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#include <sys/extent.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <stdio.h>
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#define malloc(s, t, flags) malloc(s)
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#define free(p, t) free(p)
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#define tsleep(chan, pri, str, timo) (EWOULDBLOCK)
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#define wakeup(chan) ((void)0)
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#endif
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static void extent_insert_and_optimize __P((struct extent *, u_long, u_long,
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int, struct extent_region *, struct extent_region *));
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static struct extent_region *extent_alloc_region_descriptor
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__P((struct extent *, int));
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static void extent_free_region_descriptor __P((struct extent *,
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struct extent_region *));
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/*
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* Macro to align to an arbitrary power-of-two boundary.
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*/
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#define EXTENT_ALIGN(_start, _align) \
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(((_start) + ((_align) - 1)) & (-(_align)))
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/*
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* Allocate and initialize an extent map.
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*/
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struct extent *
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extent_create(name, start, end, mtype, storage, storagesize, flags)
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const char *name;
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u_long start, end;
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int mtype;
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caddr_t storage;
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size_t storagesize;
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int flags;
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{
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struct extent *ex;
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caddr_t cp = storage;
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size_t sz = storagesize;
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struct extent_region *rp;
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int fixed_extent = (storage != NULL);
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#ifdef DIAGNOSTIC
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/* Check arguments. */
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if (name == NULL)
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panic("extent_create: name == NULL");
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if (end < start) {
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printf("extent_create: extent `%s', start 0x%lx, end 0x%lx\n",
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name, start, end);
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panic("extent_create: end < start");
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}
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if (fixed_extent && (storagesize < sizeof(struct extent_fixed)))
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panic("extent_create: fixed extent, bad storagesize 0x%x",
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storagesize);
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if (fixed_extent == 0 && (storagesize != 0 || storage != NULL))
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panic("extent_create: storage provided for non-fixed");
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#endif
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/* Allocate extent descriptor. */
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if (fixed_extent) {
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struct extent_fixed *fex;
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bzero(storage, storagesize);
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/*
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* Align all descriptors on "long" boundaries.
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*/
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fex = (struct extent_fixed *)cp;
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ex = (struct extent *)fex;
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cp += ALIGN(sizeof(struct extent_fixed));
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sz -= ALIGN(sizeof(struct extent_fixed));
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fex->fex_storage = storage;
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fex->fex_storagesize = storagesize;
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/*
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* In a fixed extent, we have to pre-allocate region
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* descriptors and place them in the extent's freelist.
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*/
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LIST_INIT(&fex->fex_freelist);
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while (sz >= ALIGN(sizeof(struct extent_region))) {
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rp = (struct extent_region *)cp;
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cp += ALIGN(sizeof(struct extent_region));
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sz -= ALIGN(sizeof(struct extent_region));
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LIST_INSERT_HEAD(&fex->fex_freelist, rp, er_link);
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}
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} else {
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ex = (struct extent *)malloc(sizeof(struct extent),
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mtype, (flags & EX_WAITOK) ? M_WAITOK : M_NOWAIT);
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if (ex == NULL)
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return (NULL);
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}
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/* Fill in the extent descriptor and return it to the caller. */
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simple_lock_init(&ex->ex_slock);
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LIST_INIT(&ex->ex_regions);
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ex->ex_name = name;
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ex->ex_start = start;
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ex->ex_end = end;
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ex->ex_mtype = mtype;
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ex->ex_flags = 0;
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if (fixed_extent)
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ex->ex_flags |= EXF_FIXED;
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if (flags & EX_NOCOALESCE)
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ex->ex_flags |= EXF_NOCOALESCE;
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return (ex);
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}
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/*
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* Destroy an extent map.
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*/
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void
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extent_destroy(ex)
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struct extent *ex;
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{
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struct extent_region *rp, *orp;
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#ifdef DIAGNOSTIC
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/* Check arguments. */
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if (ex == NULL)
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panic("extent_destroy: NULL extent");
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#endif
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simple_lock(&ex->ex_slock);
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/* Free all region descriptors in extent. */
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for (rp = ex->ex_regions.lh_first; rp != NULL; ) {
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orp = rp;
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rp = rp->er_link.le_next;
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LIST_REMOVE(orp, er_link);
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extent_free_region_descriptor(ex, orp);
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}
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/* If we're not a fixed extent, free the extent descriptor itself. */
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if ((ex->ex_flags & EXF_FIXED) == 0)
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free(ex, ex->ex_mtype);
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}
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/*
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* Insert a region descriptor into the sorted region list after the
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* entry "after" or at the head of the list (if "after" is NULL).
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* The region descriptor we insert is passed in "rp". We must
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* allocate the region descriptor before calling this function!
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* If we don't need the region descriptor, it will be freed here.
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*/
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static void
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extent_insert_and_optimize(ex, start, size, flags, after, rp)
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struct extent *ex;
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u_long start, size;
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int flags;
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struct extent_region *after, *rp;
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{
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struct extent_region *nextr;
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int appended = 0;
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if (after == NULL) {
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/*
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* We're the first in the region list. If there's
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* a region after us, attempt to coalesce to save
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* descriptor overhead.
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*/
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if (((ex->ex_flags & EXF_NOCOALESCE) == 0) &&
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(ex->ex_regions.lh_first != NULL) &&
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((start + size) == ex->ex_regions.lh_first->er_start)) {
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/*
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* We can coalesce. Prepend us to the first region.
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*/
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ex->ex_regions.lh_first->er_start = start;
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extent_free_region_descriptor(ex, rp);
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return;
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}
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/*
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* Can't coalesce. Fill in the region descriptor
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* in, and insert us at the head of the region list.
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*/
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rp->er_start = start;
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rp->er_end = start + (size - 1);
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LIST_INSERT_HEAD(&ex->ex_regions, rp, er_link);
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return;
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}
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/*
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* If EXF_NOCOALESCE is set, coalescing is disallowed.
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*/
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if (ex->ex_flags & EXF_NOCOALESCE)
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goto cant_coalesce;
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/*
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* Attempt to coalesce with the region before us.
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*/
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if ((after->er_end + 1) == start) {
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/*
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* We can coalesce. Append ourselves and make
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* note of it.
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*/
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after->er_end = start + (size - 1);
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appended = 1;
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}
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/*
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* Attempt to coalesce with the region after us.
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*/
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if ((after->er_link.le_next != NULL) &&
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((start + size) == after->er_link.le_next->er_start)) {
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/*
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* We can coalesce. Note that if we appended ourselves
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* to the previous region, we exactly fit the gap, and
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* can free the "next" region descriptor.
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*/
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if (appended) {
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/*
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* Yup, we can free it up.
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*/
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after->er_end = after->er_link.le_next->er_end;
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nextr = after->er_link.le_next;
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LIST_REMOVE(nextr, er_link);
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extent_free_region_descriptor(ex, nextr);
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} else {
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/*
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* Nope, just prepend us to the next region.
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*/
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after->er_link.le_next->er_start = start;
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}
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extent_free_region_descriptor(ex, rp);
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return;
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}
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/*
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* We weren't able to coalesce with the next region, but
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* we don't need to allocate a region descriptor if we
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* appended ourselves to the previous region.
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*/
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if (appended) {
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extent_free_region_descriptor(ex, rp);
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return;
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}
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cant_coalesce:
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/*
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* Fill in the region descriptor and insert ourselves
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* into the region list.
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*/
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rp->er_start = start;
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rp->er_end = start + (size - 1);
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LIST_INSERT_AFTER(after, rp, er_link);
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}
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/*
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* Allocate a specific region in an extent map.
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*/
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int
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extent_alloc_region(ex, start, size, flags)
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struct extent *ex;
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u_long start, size;
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int flags;
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{
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struct extent_region *rp, *last, *myrp;
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u_long end = start + (size - 1);
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int error;
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#ifdef DIAGNOSTIC
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/* Check arguments. */
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if (ex == NULL)
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panic("extent_alloc_region: NULL extent");
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if (size < 1) {
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printf("extent_alloc_region: extent `%s', size 0x%lx\n",
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ex->ex_name, size);
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panic("extent_alloc_region: bad size");
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}
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if (end < start) {
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printf(
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"extent_alloc_region: extent `%s', start 0x%lx, size 0x%lx\n",
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ex->ex_name, start, size);
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panic("extent_alloc_region: overflow");
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}
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#endif
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/*
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* Make sure the requested region lies within the
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* extent.
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*
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* We don't lock to check the range, because those values
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* are never modified, and if another thread deletes the
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* extent, we're screwed anyway.
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*/
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if ((start < ex->ex_start) || (end > ex->ex_end)) {
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#ifdef DIAGNOSTIC
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printf("extent_alloc_region: extent `%s' (0x%lx - 0x%lx)\n",
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ex->ex_name, ex->ex_start, ex->ex_end);
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printf("extent_alloc_region: start 0x%lx, end 0x%lx\n",
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start, end);
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panic("extent_alloc_region: region lies outside extent");
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#else
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return (EINVAL);
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#endif
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}
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/*
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* Allocate the region descriptor. It will be freed later
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* if we can coalesce with another region. Don't lock before
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* here! This could block.
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*/
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myrp = extent_alloc_region_descriptor(ex, flags);
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if (myrp == NULL) {
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#ifdef DIAGNOSTIC
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printf(
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"extent_alloc_region: can't allocate region descriptor\n");
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#endif
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return (ENOMEM);
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}
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alloc_start:
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simple_lock(&ex->ex_slock);
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/*
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* Attempt to place ourselves in the desired area of the
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* extent. We save ourselves some work by keeping the list sorted.
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* In other words, if the start of the current region is greater
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* than the end of our region, we don't have to search any further.
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*/
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/*
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* Keep a pointer to the last region we looked at so
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* that we don't have to traverse the list again when
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* we insert ourselves. If "last" is NULL when we
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* finally insert ourselves, we go at the head of the
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* list. See extent_insert_and_optimize() for details.
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*/
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last = NULL;
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for (rp = ex->ex_regions.lh_first; rp != NULL;
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rp = rp->er_link.le_next) {
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if (rp->er_start > end) {
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/*
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* We lie before this region and don't
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* conflict.
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*/
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break;
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}
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/*
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* The current region begins before we end.
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* Check for a conflict.
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*/
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if (rp->er_end >= start) {
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/*
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* We conflict. If we can (and want to) wait,
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* do so.
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*/
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if (flags & EX_WAITSPACE) {
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ex->ex_flags |= EXF_WANTED;
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simple_unlock(&ex->ex_slock);
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error = tsleep(ex,
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PRIBIO | ((flags & EX_CATCH) ? PCATCH : 0),
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"extnt", 0);
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if (error)
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return (error);
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goto alloc_start;
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}
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extent_free_region_descriptor(ex, myrp);
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simple_unlock(&ex->ex_slock);
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return (EAGAIN);
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}
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/*
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* We don't conflict, but this region lies before
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* us. Keep a pointer to this region, and keep
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* trying.
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*/
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last = rp;
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}
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/*
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* We don't conflict with any regions. "last" points
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* to the region we fall after, or is NULL if we belong
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* at the beginning of the region list. Insert ourselves.
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*/
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extent_insert_and_optimize(ex, start, size, flags, last, myrp);
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simple_unlock(&ex->ex_slock);
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return (0);
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}
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/*
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* Macro to check (x + y) <= z. This check is designed to fail
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* if an overflow occurs.
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*/
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#define LE_OV(x, y, z) ((((x) + (y)) >= (x)) && (((x) + (y)) <= (z)))
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/*
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* Allocate a region in an extent map subregion.
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*
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* If EX_FAST is specified, we return the first fit in the map.
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* Otherwise, we try to minimize fragmentation by finding the
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* smallest gap that will hold the request.
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*
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* The allocated region is aligned to "alignment", which must be
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* a power of 2.
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*/
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int
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extent_alloc_subregion(ex, substart, subend, size, alignment, boundary,
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flags, result)
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struct extent *ex;
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u_long substart, subend, size, alignment, boundary;
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int flags;
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u_long *result;
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{
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struct extent_region *rp, *myrp, *last, *bestlast;
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u_long newstart, newend, beststart, bestovh, ovh;
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u_long dontcross, odontcross;
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int error;
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|
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#ifdef DIAGNOSTIC
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/*
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* Check arguments.
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*
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* We don't lock to check these, because these values
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* are never modified, and if another thread deletes the
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* extent, we're screwed anyway.
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*/
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if (ex == NULL)
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panic("extent_alloc_subregion: NULL extent");
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if (result == NULL)
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panic("extent_alloc_subregion: NULL result pointer");
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if ((substart < ex->ex_start) || (substart > ex->ex_end) ||
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(subend > ex->ex_end) || (subend < ex->ex_start)) {
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printf("extent_alloc_subregion: extent `%s', ex_start 0x%lx, ex_end 0x%lx\n",
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ex->ex_name, ex->ex_start, ex->ex_end);
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printf("extent_alloc_subregion: substart 0x%lx, subend 0x%lx\n",
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substart, subend);
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panic("extent_alloc_subregion: bad subregion");
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}
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if ((size < 1) || ((size - 1) > (subend - substart))) {
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printf("extent_alloc_subregion: extent `%s', size 0x%lx\n",
|
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ex->ex_name, size);
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panic("extent_alloc_subregion: bad size");
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}
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if (alignment == 0)
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panic("extent_alloc_subregion: bad alignment");
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if (boundary && (boundary < size)) {
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printf(
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"extent_alloc_subregion: extent `%s', size 0x%lx,
|
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boundary 0x%lx\n", ex->ex_name, size, boundary);
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panic("extent_alloc_subregion: bad boundary");
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}
|
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#endif
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|
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/*
|
|
* Allocate the region descriptor. It will be freed later
|
|
* if we can coalesce with another region. Don't lock before
|
|
* here! This could block.
|
|
*/
|
|
myrp = extent_alloc_region_descriptor(ex, flags);
|
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if (myrp == NULL) {
|
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#ifdef DIAGNOSTIC
|
|
printf(
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|
"extent_alloc_subregion: can't allocate region descriptor\n");
|
|
#endif
|
|
return (ENOMEM);
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}
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alloc_start:
|
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simple_lock(&ex->ex_slock);
|
|
|
|
/*
|
|
* Keep a pointer to the last region we looked at so
|
|
* that we don't have to traverse the list again when
|
|
* we insert ourselves. If "last" is NULL when we
|
|
* finally insert ourselves, we go at the head of the
|
|
* list. See extent_insert_and_optimize() for deatails.
|
|
*/
|
|
last = NULL;
|
|
|
|
/*
|
|
* Initialize the "don't cross" boundary, a.k.a a line
|
|
* that a region should not cross. If the boundary lies
|
|
* before the region starts, we add the "boundary" argument
|
|
* until we get a meaningful comparison.
|
|
*
|
|
* Start the boundary lines at 0 if the caller requests it.
|
|
*/
|
|
dontcross = 0;
|
|
if (boundary) {
|
|
dontcross =
|
|
((flags & EX_BOUNDZERO) ? 0 : ex->ex_start) + boundary;
|
|
while (dontcross < substart)
|
|
dontcross += boundary;
|
|
}
|
|
|
|
/*
|
|
* Keep track of size and location of the smallest
|
|
* chunk we fit in.
|
|
*
|
|
* Since the extent can be as large as the numeric range
|
|
* of the CPU (0 - 0xffffffff for 32-bit systems), the
|
|
* best overhead value can be the maximum unsigned integer.
|
|
* Thus, we initialize "bestovh" to 0, since we insert ourselves
|
|
* into the region list immediately on an exact match (which
|
|
* is the only case where "bestovh" would be set to 0).
|
|
*/
|
|
bestovh = 0;
|
|
beststart = 0;
|
|
bestlast = NULL;
|
|
|
|
/*
|
|
* For N allocated regions, we must make (N + 1)
|
|
* checks for unallocated space. The first chunk we
|
|
* check is the area from the beginning of the subregion
|
|
* to the first allocated region after that point.
|
|
*/
|
|
newstart = EXTENT_ALIGN(substart, alignment);
|
|
if (newstart < ex->ex_start) {
|
|
#ifdef DIAGNOSTIC
|
|
printf(
|
|
"extent_alloc_subregion: extent `%s' (0x%lx - 0x%lx), alignment 0x%lx\n",
|
|
ex->ex_name, ex->ex_start, ex->ex_end, alignment);
|
|
simple_unlock(&ex->ex_slock);
|
|
panic("extent_alloc_subregion: overflow after alignment");
|
|
#else
|
|
extent_free_region_descriptor(ex, myrp);
|
|
simple_unlock(&ex->ex_slock);
|
|
return (EINVAL);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Find the first allocated region that begins on or after
|
|
* the subregion start, advancing the "last" pointer along
|
|
* the way.
|
|
*/
|
|
for (rp = ex->ex_regions.lh_first; rp != NULL;
|
|
rp = rp->er_link.le_next) {
|
|
if (rp->er_start >= newstart)
|
|
break;
|
|
last = rp;
|
|
}
|
|
|
|
for (; rp != NULL; rp = rp->er_link.le_next) {
|
|
/*
|
|
* Check the chunk before "rp". Note that our
|
|
* comparison is safe from overflow conditions.
|
|
*/
|
|
if (LE_OV(newstart, size, rp->er_start)) {
|
|
/*
|
|
* Do a boundary check, if necessary. Note
|
|
* that a region may *begin* on the boundary,
|
|
* but it must end before the boundary.
|
|
*/
|
|
if (boundary) {
|
|
newend = newstart + (size - 1);
|
|
|
|
/*
|
|
* Adjust boundary for a meaningful
|
|
* comparison.
|
|
*/
|
|
while (dontcross <= newstart) {
|
|
odontcross = dontcross;
|
|
dontcross += boundary;
|
|
|
|
/*
|
|
* If we run past the end of
|
|
* the extent or the boundary
|
|
* overflows, then the request
|
|
* can't fit.
|
|
*/
|
|
if ((dontcross > ex->ex_end) ||
|
|
(dontcross < odontcross))
|
|
goto fail;
|
|
}
|
|
|
|
/* Do the boundary check. */
|
|
if (newend >= dontcross) {
|
|
/*
|
|
* Candidate region crosses
|
|
* boundary. Try again.
|
|
*/
|
|
continue;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We would fit into this space. Calculate
|
|
* the overhead (wasted space). If we exactly
|
|
* fit, or we're taking the first fit, insert
|
|
* ourselves into the region list.
|
|
*/
|
|
ovh = rp->er_start - newstart - size;
|
|
if ((flags & EX_FAST) || (ovh == 0))
|
|
goto found;
|
|
|
|
/*
|
|
* Don't exactly fit, but check to see
|
|
* if we're better than any current choice.
|
|
*/
|
|
if ((bestovh == 0) || (ovh < bestovh)) {
|
|
bestovh = ovh;
|
|
beststart = newstart;
|
|
bestlast = last;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Skip past the current region and check again.
|
|
*/
|
|
newstart = EXTENT_ALIGN((rp->er_end + 1), alignment);
|
|
if (newstart < rp->er_end) {
|
|
/*
|
|
* Overflow condition. Don't error out, since
|
|
* we might have a chunk of space that we can
|
|
* use.
|
|
*/
|
|
goto fail;
|
|
}
|
|
|
|
last = rp;
|
|
}
|
|
|
|
/*
|
|
* The final check is from the current starting point to the
|
|
* end of the subregion. If there were no allocated regions,
|
|
* "newstart" is set to the beginning of the subregion, or
|
|
* just past the end of the last allocated region, adjusted
|
|
* for alignment in either case.
|
|
*/
|
|
if (LE_OV(newstart, (size - 1), subend)) {
|
|
/*
|
|
* We would fit into this space. Calculate
|
|
* the overhead (wasted space). If we exactly
|
|
* fit, or we're taking the first fit, insert
|
|
* ourselves into the region list.
|
|
*/
|
|
ovh = ex->ex_end - newstart - (size - 1);
|
|
if ((flags & EX_FAST) || (ovh == 0))
|
|
goto found;
|
|
|
|
/*
|
|
* Don't exactly fit, but check to see
|
|
* if we're better than any current choice.
|
|
*/
|
|
if ((bestovh == 0) || (ovh < bestovh)) {
|
|
bestovh = ovh;
|
|
beststart = newstart;
|
|
bestlast = last;
|
|
}
|
|
}
|
|
|
|
fail:
|
|
/*
|
|
* One of the following two conditions have
|
|
* occurred:
|
|
*
|
|
* There is no chunk large enough to hold the request.
|
|
*
|
|
* If EX_FAST was not specified, there is not an
|
|
* exact match for the request.
|
|
*
|
|
* Note that if we reach this point and EX_FAST is
|
|
* set, then we know there is no space in the extent for
|
|
* the request.
|
|
*/
|
|
if (((flags & EX_FAST) == 0) && (bestovh != 0)) {
|
|
/*
|
|
* We have a match that's "good enough".
|
|
*/
|
|
newstart = beststart;
|
|
last = bestlast;
|
|
goto found;
|
|
}
|
|
|
|
/*
|
|
* No space currently available. Wait for it to free up,
|
|
* if possible.
|
|
*/
|
|
if (flags & EX_WAITSPACE) {
|
|
ex->ex_flags |= EXF_WANTED;
|
|
simple_unlock(&ex->ex_slock);
|
|
error = tsleep(ex,
|
|
PRIBIO | ((flags & EX_CATCH) ? PCATCH : 0), "extnt", 0);
|
|
if (error)
|
|
return (error);
|
|
goto alloc_start;
|
|
}
|
|
|
|
extent_free_region_descriptor(ex, myrp);
|
|
simple_unlock(&ex->ex_slock);
|
|
return (EAGAIN);
|
|
|
|
found:
|
|
/*
|
|
* Insert ourselves into the region list.
|
|
*/
|
|
extent_insert_and_optimize(ex, newstart, size, flags, last, myrp);
|
|
simple_unlock(&ex->ex_slock);
|
|
*result = newstart;
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
extent_free(ex, start, size, flags)
|
|
struct extent *ex;
|
|
u_long start, size;
|
|
int flags;
|
|
{
|
|
struct extent_region *rp, *nrp = NULL;
|
|
u_long end = start + (size - 1);
|
|
int exflags;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
/*
|
|
* Check arguments.
|
|
*
|
|
* We don't lock to check these, because these values
|
|
* are never modified, and if another thread deletes the
|
|
* extent, we're screwed anyway.
|
|
*/
|
|
if (ex == NULL)
|
|
panic("extent_free: NULL extent");
|
|
if ((start < ex->ex_start) || (start > ex->ex_end)) {
|
|
extent_print(ex);
|
|
printf("extent_free: extent `%s', start 0x%lx, size 0x%lx\n",
|
|
ex->ex_name, start, size);
|
|
panic("extent_free: extent `%s', region not within extent",
|
|
ex->ex_name);
|
|
}
|
|
/* Check for an overflow. */
|
|
if (end < start) {
|
|
extent_print(ex);
|
|
printf("extent_free: extent `%s', start 0x%lx, size 0x%lx\n",
|
|
ex->ex_name, start, size);
|
|
panic("extent_free: overflow");
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* If we're allowing coalescing, we must allocate a region
|
|
* descriptor now, since it might block.
|
|
*
|
|
* XXX Make a static, create-time flags word, so we don't
|
|
* XXX have to lock to read it!
|
|
*/
|
|
simple_lock(&ex->ex_slock);
|
|
exflags = ex->ex_flags;
|
|
simple_unlock(&ex->ex_slock);
|
|
if ((exflags & EXF_NOCOALESCE) == 0) {
|
|
/* Allocate a region descriptor. */
|
|
nrp = extent_alloc_region_descriptor(ex, flags);
|
|
if (nrp == NULL)
|
|
return (ENOMEM);
|
|
}
|
|
|
|
simple_lock(&ex->ex_slock);
|
|
|
|
/*
|
|
* Find region and deallocate. Several possibilities:
|
|
*
|
|
* 1. (start == er_start) && (end == er_end):
|
|
* Free descriptor.
|
|
*
|
|
* 2. (start == er_start) && (end < er_end):
|
|
* Adjust er_start.
|
|
*
|
|
* 3. (start > er_start) && (end == er_end):
|
|
* Adjust er_end.
|
|
*
|
|
* 4. (start > er_start) && (end < er_end):
|
|
* Fragment region. Requires descriptor alloc.
|
|
*
|
|
* Cases 2, 3, and 4 require that the EXF_NOCOALESCE flag
|
|
* is not set.
|
|
*/
|
|
for (rp = ex->ex_regions.lh_first; rp != NULL;
|
|
rp = rp->er_link.le_next) {
|
|
/*
|
|
* Save ourselves some comparisons; does the current
|
|
* region end before chunk to be freed begins? If so,
|
|
* then we haven't found the appropriate region descriptor.
|
|
*/
|
|
if (rp->er_end < start)
|
|
continue;
|
|
|
|
/*
|
|
* Save ourselves some traversal; does the current
|
|
* region begin after the chunk to be freed ends? If so,
|
|
* then we've already passed any possible region descriptors
|
|
* that might have contained the chunk to be freed.
|
|
*/
|
|
if (rp->er_start > end)
|
|
break;
|
|
|
|
/* Case 1. */
|
|
if ((start == rp->er_start) && (end == rp->er_end)) {
|
|
LIST_REMOVE(rp, er_link);
|
|
extent_free_region_descriptor(ex, rp);
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* The following cases all require that EXF_NOCOALESCE
|
|
* is not set.
|
|
*/
|
|
if (ex->ex_flags & EXF_NOCOALESCE)
|
|
continue;
|
|
|
|
/* Case 2. */
|
|
if ((start == rp->er_start) && (end < rp->er_end)) {
|
|
rp->er_start = (end + 1);
|
|
goto done;
|
|
}
|
|
|
|
/* Case 3. */
|
|
if ((start > rp->er_start) && (end == rp->er_end)) {
|
|
rp->er_end = (start - 1);
|
|
goto done;
|
|
}
|
|
|
|
/* Case 4. */
|
|
if ((start > rp->er_start) && (end < rp->er_end)) {
|
|
/* Fill in new descriptor. */
|
|
nrp->er_start = end + 1;
|
|
nrp->er_end = rp->er_end;
|
|
|
|
/* Adjust current descriptor. */
|
|
rp->er_end = start - 1;
|
|
|
|
/* Instert new descriptor after current. */
|
|
LIST_INSERT_AFTER(rp, nrp, er_link);
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
/* Region not found, or request otherwise invalid. */
|
|
simple_unlock(&ex->ex_slock);
|
|
extent_print(ex);
|
|
printf("extent_free: start 0x%lx, end 0x%lx\n", start, end);
|
|
panic("extent_free: region not found");
|
|
|
|
done:
|
|
if (ex->ex_flags & EXF_WANTED) {
|
|
ex->ex_flags &= ~EXF_WANTED;
|
|
wakeup(ex);
|
|
}
|
|
simple_unlock(&ex->ex_slock);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Allocate an extent region descriptor. EXTENT MUST NOT BE LOCKED,
|
|
* AS THIS FUNCTION MAY BLOCK! We will handle any locking we may need.
|
|
*/
|
|
static struct extent_region *
|
|
extent_alloc_region_descriptor(ex, flags)
|
|
struct extent *ex;
|
|
int flags;
|
|
{
|
|
struct extent_region *rp;
|
|
int exflags;
|
|
|
|
/*
|
|
* XXX Make a static, create-time flags word, so we don't
|
|
* XXX have to lock to read it!
|
|
*/
|
|
simple_lock(&ex->ex_slock);
|
|
exflags = ex->ex_flags;
|
|
simple_unlock(&ex->ex_slock);
|
|
|
|
if (exflags & EXF_FIXED) {
|
|
struct extent_fixed *fex = (struct extent_fixed *)ex;
|
|
|
|
for (;;) {
|
|
simple_lock(&ex->ex_slock);
|
|
if ((rp = fex->fex_freelist.lh_first) != NULL) {
|
|
/*
|
|
* Don't muck with flags after pulling it off
|
|
* the freelist; it may have been dynamically
|
|
* allocated, and kindly given to us. We
|
|
* need to remember that information.
|
|
*/
|
|
LIST_REMOVE(rp, er_link);
|
|
simple_unlock(&ex->ex_slock);
|
|
return (rp);
|
|
}
|
|
if (flags & EX_MALLOCOK) {
|
|
simple_unlock(&ex->ex_slock);
|
|
goto alloc;
|
|
}
|
|
if ((flags & EX_WAITOK) == 0) {
|
|
simple_unlock(&ex->ex_slock);
|
|
return (NULL);
|
|
}
|
|
ex->ex_flags |= EXF_FLWANTED;
|
|
simple_unlock(&ex->ex_slock);
|
|
if (tsleep(&fex->fex_freelist,
|
|
PRIBIO | ((flags & EX_CATCH) ? PCATCH : 0),
|
|
"extnt", 0))
|
|
return (NULL);
|
|
}
|
|
}
|
|
|
|
alloc:
|
|
rp = (struct extent_region *)
|
|
malloc(sizeof(struct extent_region), ex->ex_mtype,
|
|
(flags & EX_WAITOK) ? M_WAITOK : M_NOWAIT);
|
|
|
|
if (rp != NULL)
|
|
rp->er_flags = ER_ALLOC;
|
|
|
|
return (rp);
|
|
}
|
|
|
|
/*
|
|
* Free an extent region descriptor. EXTENT _MUST_ BE LOCKED! This
|
|
* is safe as we do not block here.
|
|
*/
|
|
static void
|
|
extent_free_region_descriptor(ex, rp)
|
|
struct extent *ex;
|
|
struct extent_region *rp;
|
|
{
|
|
|
|
if (ex->ex_flags & EXF_FIXED) {
|
|
struct extent_fixed *fex = (struct extent_fixed *)ex;
|
|
|
|
/*
|
|
* If someone's waiting for a region descriptor,
|
|
* be nice and give them this one, rather than
|
|
* just free'ing it back to the system.
|
|
*/
|
|
if (rp->er_flags & ER_ALLOC) {
|
|
if (ex->ex_flags & EXF_FLWANTED) {
|
|
/* Clear all but ER_ALLOC flag. */
|
|
rp->er_flags = ER_ALLOC;
|
|
LIST_INSERT_HEAD(&fex->fex_freelist, rp,
|
|
er_link);
|
|
goto wake_em_up;
|
|
} else {
|
|
free(rp, ex->ex_mtype);
|
|
}
|
|
} else {
|
|
/* Clear all flags. */
|
|
rp->er_flags = 0;
|
|
LIST_INSERT_HEAD(&fex->fex_freelist, rp, er_link);
|
|
}
|
|
|
|
if (ex->ex_flags & EXF_FLWANTED) {
|
|
wake_em_up:
|
|
ex->ex_flags &= ~EXF_FLWANTED;
|
|
wakeup(&fex->fex_freelist);
|
|
}
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* We know it's dynamically allocated if we get here.
|
|
*/
|
|
free(rp, ex->ex_mtype);
|
|
}
|
|
|
|
void
|
|
extent_print(ex)
|
|
struct extent *ex;
|
|
{
|
|
struct extent_region *rp;
|
|
|
|
if (ex == NULL)
|
|
panic("extent_print: NULL extent");
|
|
|
|
simple_lock(&ex->ex_slock);
|
|
|
|
printf("extent `%s' (0x%lx - 0x%lx), flags = 0x%x\n", ex->ex_name,
|
|
ex->ex_start, ex->ex_end, ex->ex_flags);
|
|
|
|
for (rp = ex->ex_regions.lh_first; rp != NULL;
|
|
rp = rp->er_link.le_next)
|
|
printf(" 0x%lx - 0x%lx\n", rp->er_start, rp->er_end);
|
|
|
|
simple_unlock(&ex->ex_slock);
|
|
}
|