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UBC was a disaster. It worked very good when it worked, but on some
machines or some configurations or in some phase of the moon (we actually
don't know when or why) files disappeared. Since we've not been able to
track down the problem in two weeks intense debugging and we need -current
to be stable, back out everything to a state it had before UBC.

We apologise for the inconvenience.

/*	$OpenBSD: uvm_amap_i.h,v 1.12 2001/12/19 08:58:07 art Exp $	*/
/*	$NetBSD: uvm_amap_i.h,v 1.15 2000/11/25 06:27:59 chs Exp $	*/

/*
 *
 * Copyright (c) 1997 Charles D. Cranor and Washington University.
 * 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 product includes software developed by Charles D. Cranor and
 *      Washington University.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * from: Id: uvm_amap_i.h,v 1.1.2.4 1998/01/05 18:12:57 chuck Exp
 */

#ifndef _UVM_UVM_AMAP_I_H_
#define _UVM_UVM_AMAP_I_H_

/*
 * uvm_amap_i.h
 */

/*
 * if inlines are enabled always pull in these functions, otherwise
 * pull them in only once (when we are compiling uvm_amap.c).
 */

#if defined(UVM_AMAP_INLINE) || defined(UVM_AMAP_C)

/*
 * amap_lookup: look up a page in an amap
 *
 * => amap should be locked by caller.
 */
AMAP_INLINE struct vm_anon *
amap_lookup(aref, offset)
	struct vm_aref *aref;
	vaddr_t offset;
{
	int slot;
	struct vm_amap *amap = aref->ar_amap;
	UVMHIST_FUNC("amap_lookup"); UVMHIST_CALLED(maphist);

	AMAP_B2SLOT(slot, offset);
	slot += aref->ar_pageoff;

	if (slot >= amap->am_nslot)
		panic("amap_lookup: offset out of range");

	UVMHIST_LOG(maphist, "<- done (amap=0x%x, offset=0x%x, result=0x%x)",
	    amap, offset, amap->am_anon[slot], 0);
	return(amap->am_anon[slot]);
}

/*
 * amap_lookups: look up a range of pages in an amap
 *
 * => amap should be locked by caller.
 * => XXXCDC: this interface is biased toward array-based amaps.  fix.
 */
AMAP_INLINE void
amap_lookups(aref, offset, anons, npages)
	struct vm_aref *aref;
	vaddr_t offset;
	struct vm_anon **anons;
	int npages;
{
	int slot;
	struct vm_amap *amap = aref->ar_amap;
	UVMHIST_FUNC("amap_lookups"); UVMHIST_CALLED(maphist);

	AMAP_B2SLOT(slot, offset);
	slot += aref->ar_pageoff;

	UVMHIST_LOG(maphist, "  slot=%d, npages=%d, nslot=%d", slot, npages,
		amap->am_nslot, 0);

	if ((slot + (npages - 1)) >= amap->am_nslot)
		panic("amap_lookups: offset out of range");

	memcpy(anons, &amap->am_anon[slot], npages * sizeof(struct vm_anon *));

	UVMHIST_LOG(maphist, "<- done", 0, 0, 0, 0);
	return;
}

/*
 * amap_add: add (or replace) a page to an amap
 *
 * => caller must lock amap.   
 * => if (replace) caller must lock anon because we might have to call
 *	pmap_page_protect on the anon's page.
 * => returns an "offset" which is meaningful to amap_unadd().
 */
AMAP_INLINE void
amap_add(aref, offset, anon, replace)
	struct vm_aref *aref;
	vaddr_t offset;
	struct vm_anon *anon;
	boolean_t replace;
{
	int slot;
	struct vm_amap *amap = aref->ar_amap;
	UVMHIST_FUNC("amap_add"); UVMHIST_CALLED(maphist);

	AMAP_B2SLOT(slot, offset);
	slot += aref->ar_pageoff;

	if (slot >= amap->am_nslot)
		panic("amap_add: offset out of range");

	if (replace) {

		if (amap->am_anon[slot] == NULL)
			panic("amap_add: replacing null anon");
		if (amap->am_anon[slot]->u.an_page != NULL && 
		    (amap->am_flags & AMAP_SHARED) != 0) {
			pmap_page_protect(amap->am_anon[slot]->u.an_page,
			    VM_PROT_NONE);
			/*
			 * XXX: suppose page is supposed to be wired somewhere?
			 */
		}
	} else {   /* !replace */
		if (amap->am_anon[slot] != NULL)
			panic("amap_add: slot in use");

		amap->am_bckptr[slot] = amap->am_nused;
		amap->am_slots[amap->am_nused] = slot;
		amap->am_nused++;
	}
	amap->am_anon[slot] = anon;
	UVMHIST_LOG(maphist,
	    "<- done (amap=0x%x, offset=0x%x, anon=0x%x, rep=%d)",
	    amap, offset, anon, replace);
}

/*
 * amap_unadd: remove a page from an amap
 *
 * => caller must lock amap
 */
AMAP_INLINE void
amap_unadd(aref, offset)
	struct vm_aref *aref;
	vaddr_t offset;
{
	int ptr, slot;
	struct vm_amap *amap = aref->ar_amap;
	UVMHIST_FUNC("amap_unadd"); UVMHIST_CALLED(maphist);

	AMAP_B2SLOT(slot, offset);
	slot += aref->ar_pageoff;

	if (slot >= amap->am_nslot)
		panic("amap_unadd: offset out of range");

	if (amap->am_anon[slot] == NULL)
		panic("amap_unadd: nothing there");

	amap->am_anon[slot] = NULL;
	ptr = amap->am_bckptr[slot];

	if (ptr != (amap->am_nused - 1)) {	/* swap to keep slots contig? */
		amap->am_slots[ptr] = amap->am_slots[amap->am_nused - 1];
		amap->am_bckptr[amap->am_slots[ptr]] = ptr;	/* back link */
	}
	amap->am_nused--;
	UVMHIST_LOG(maphist, "<- done (amap=0x%x, slot=0x%x)", amap, slot,0, 0);
}

/*
 * amap_ref: gain a reference to an amap
 *
 * => amap must not be locked (we will lock)
 * => "offset" and "len" are in units of pages
 * => called at fork time to gain the child's reference
 */
AMAP_INLINE void
amap_ref(amap, offset, len, flags)
	struct vm_amap *amap;
	vaddr_t offset;
	vsize_t len;
	int flags;
{
	UVMHIST_FUNC("amap_ref"); UVMHIST_CALLED(maphist);

	amap_lock(amap);
	amap->am_ref++;
	if (flags & AMAP_SHARED)
		amap->am_flags |= AMAP_SHARED;
#ifdef UVM_AMAP_PPREF
	if (amap->am_ppref == NULL && (flags & AMAP_REFALL) == 0 &&
	    len != amap->am_nslot)
		amap_pp_establish(amap);
	if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
		if (flags & AMAP_REFALL)
			amap_pp_adjref(amap, 0, amap->am_nslot, 1);
		else
			amap_pp_adjref(amap, offset, len, 1);
	}
#endif
	amap_unlock(amap);
	UVMHIST_LOG(maphist,"<- done!  amap=0x%x", amap, 0, 0, 0);
}

/*
 * amap_unref: remove a reference to an amap
 *
 * => caller must remove all pmap-level references to this amap before
 *	dropping the reference
 * => called from uvm_unmap_detach [only]  ... note that entry is no
 *	longer part of a map and thus has no need for locking
 * => amap must be unlocked (we will lock it).
 */
AMAP_INLINE void
amap_unref(amap, offset, len, all)
	struct vm_amap *amap;
	vaddr_t offset;
	vsize_t len;
	boolean_t all;
{
	UVMHIST_FUNC("amap_unref"); UVMHIST_CALLED(maphist);

	/*
	 * lock it
	 */
	amap_lock(amap);
	UVMHIST_LOG(maphist,"  amap=0x%x  refs=%d, nused=%d",
	    amap, amap->am_ref, amap->am_nused, 0);

	/*
	 * if we are the last reference, free the amap and return.
	 */

	if (amap->am_ref == 1) {
		amap_wipeout(amap);	/* drops final ref and frees */
		UVMHIST_LOG(maphist,"<- done (was last ref)!", 0, 0, 0, 0);
		return;			/* no need to unlock */
	}

	/*
	 * otherwise just drop the reference count(s)
	 */

	amap->am_ref--;
	if (amap->am_ref == 1 && (amap->am_flags & AMAP_SHARED) != 0)
		amap->am_flags &= ~AMAP_SHARED;	/* clear shared flag */
#ifdef UVM_AMAP_PPREF
	if (amap->am_ppref == NULL && all == 0 && len != amap->am_nslot)
		amap_pp_establish(amap);
	if (amap->am_ppref && amap->am_ppref != PPREF_NONE) {
		if (all)
			amap_pp_adjref(amap, 0, amap->am_nslot, -1);
		else
			amap_pp_adjref(amap, offset, len, -1);
	}
#endif
	amap_unlock(amap);

	UVMHIST_LOG(maphist,"<- done!", 0, 0, 0, 0);
}

#endif /* defined(UVM_AMAP_INLINE) || defined(UVM_AMAP_C) */

#endif /* _UVM_UVM_AMAP_I_H_ */