[unix-history] / sys / vm / device_pager.c

/*
 * Copyright (c) 1990 University of Utah.
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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 the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 *	@(#)device_pager.c	8.1 (Berkeley) 6/11/93
 */

/*
 * Page to/from special files.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/mman.h>
#include <sys/malloc.h>

#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/device_pager.h>

#include "vnode.h"
#include "specdev.h"

queue_head_t	dev_pager_list;		/* list of managed devices */
queue_head_t	dev_pager_fakelist;	/* list of available vm_page_t's */

#ifdef DEBUG
int	dpagerdebug = 0;
#define	DDB_FOLLOW	0x01
#define DDB_INIT	0x02
#define DDB_ALLOC	0x04
#define DDB_FAIL	0x08
#endif

static vm_pager_t	 dev_pager_alloc
			    __P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
static void		 dev_pager_dealloc __P((vm_pager_t));
static int		 dev_pager_getpage
			    __P((vm_pager_t, vm_page_t, boolean_t));
static boolean_t	 dev_pager_haspage __P((vm_pager_t, vm_offset_t));
static void		 dev_pager_init __P((void));
static int		 dev_pager_putpage
			    __P((vm_pager_t, vm_page_t, boolean_t));
static vm_page_t	 dev_pager_getfake __P((vm_offset_t));
static void		 dev_pager_putfake __P((vm_page_t));

struct pagerops devicepagerops = {
	dev_pager_init,
	dev_pager_alloc,
	dev_pager_dealloc,
	dev_pager_getpage,
	0,
	dev_pager_putpage,
	0,
	dev_pager_haspage
};

static void
dev_pager_init()
{
#ifdef DEBUG
	if (dpagerdebug & DDB_FOLLOW)
		printf("dev_pager_init()\n");
#endif
	queue_init(&dev_pager_list);
	queue_init(&dev_pager_fakelist);
}

static vm_pager_t
dev_pager_alloc(handle, size, prot, foff)
	caddr_t handle;
	vm_size_t size;
	vm_prot_t prot;
	vm_offset_t foff;
{
	dev_t dev;
	vm_pager_t pager;
	int (*mapfunc)();
	vm_object_t object;
	dev_pager_t devp;
	unsigned int npages, off;

#ifdef DEBUG
	if (dpagerdebug & DDB_FOLLOW)
		printf("dev_pager_alloc(%x, %x, %x, %x)\n",
		       handle, size, prot, foff);
#endif
#ifdef DIAGNOSTIC
	/*
	 * Pageout to device, should never happen.
	 */
	if (handle == NULL)
		panic("dev_pager_alloc called");
#endif

	/*
	 * Make sure this device can be mapped.
	 */
	dev = (dev_t)(u_long)handle;
	mapfunc = cdevsw[major(dev)].d_mmap;
	if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop)
		return(NULL);

	/*
	 * Offset should be page aligned.
	 */
	if (foff & (PAGE_SIZE-1))
		return(NULL);

	/*
	 * Check that the specified range of the device allows the
	 * desired protection.
	 *
	 * XXX assumes VM_PROT_* == PROT_*
	 */
	npages = atop(round_page(size));
	for (off = foff; npages--; off += PAGE_SIZE)
		if ((*mapfunc)(dev, off, (int)prot) == -1)
			return(NULL);

	/*
	 * Look up pager, creating as necessary.
	 */
top:
	pager = vm_pager_lookup(&dev_pager_list, handle);
	if (pager == NULL) {
		/*
		 * Allocate and initialize pager structs
		 */
		pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
		if (pager == NULL)
			return(NULL);
		devp = (dev_pager_t)malloc(sizeof *devp, M_VMPGDATA, M_WAITOK);
		if (devp == NULL) {
			free((caddr_t)pager, M_VMPAGER);
			return(NULL);
		}
		pager->pg_handle = handle;
		pager->pg_ops = &devicepagerops;
		pager->pg_type = PG_DEVICE;
		pager->pg_data = (caddr_t)devp;
		queue_init(&devp->devp_pglist);
		/*
		 * Allocate object and associate it with the pager.
		 */
		object = devp->devp_object = vm_object_allocate(0);
		vm_object_enter(object, pager);
		vm_object_setpager(object, pager, (vm_offset_t)foff, FALSE);
		/*
		 * Finally, put it on the managed list so other can find it.
		 * First we re-lookup in case someone else beat us to this
		 * point (due to blocking in the various mallocs).  If so,
		 * we free everything and start over.
		 */
		if (vm_pager_lookup(&dev_pager_list, handle)) {
			free((caddr_t)devp, M_VMPGDATA);
			free((caddr_t)pager, M_VMPAGER);
			goto top;
		}
		queue_enter(&dev_pager_list, pager, vm_pager_t, pg_list);
#ifdef DEBUG
		if (dpagerdebug & DDB_ALLOC) {
			printf("dev_pager_alloc: pager %x devp %x object %x\n",
			       pager, devp, object);
			vm_object_print(object, FALSE);
		}
#endif
	} else {
		/*
		 * vm_object_lookup() gains a reference and also
		 * removes the object from the cache.
		 */
		object = vm_object_lookup(pager);
#ifdef DIAGNOSTIC
		devp = (dev_pager_t)pager->pg_data;
		if (object != devp->devp_object)
			panic("dev_pager_setup: bad object");
#endif
	}
	return(pager);
}

static void
dev_pager_dealloc(pager)
	vm_pager_t pager;
{
	dev_pager_t devp;
	vm_object_t object;
	vm_page_t m;

#ifdef DEBUG
	if (dpagerdebug & DDB_FOLLOW)
		printf("dev_pager_dealloc(%x)\n", pager);
#endif
	queue_remove(&dev_pager_list, pager, vm_pager_t, pg_list);
	/*
	 * Get the object.
	 * Note: cannot use vm_object_lookup since object has already
	 * been removed from the hash chain.
	 */
	devp = (dev_pager_t)pager->pg_data;
	object = devp->devp_object;
#ifdef DEBUG
	if (dpagerdebug & DDB_ALLOC)
		printf("dev_pager_dealloc: devp %x object %x\n", devp, object);
#endif
	/*
	 * Free up our fake pages.
	 */
	while (!queue_empty(&devp->devp_pglist)) {
		queue_remove_first(&devp->devp_pglist, m, vm_page_t, pageq);
		dev_pager_putfake(m);
	}
	free((caddr_t)devp, M_VMPGDATA);
	free((caddr_t)pager, M_VMPAGER);
}

static int
dev_pager_getpage(pager, m, sync)
	vm_pager_t pager;
	vm_page_t m;
	boolean_t sync;
{
	register vm_object_t object;
	vm_offset_t offset, paddr;
	vm_page_t page;
	dev_t dev;
	int s;
	int (*mapfunc)(), prot;

#ifdef DEBUG
	if (dpagerdebug & DDB_FOLLOW)
		printf("dev_pager_getpage(%x, %x)\n", pager, m);
#endif

	object = m->object;
	dev = (dev_t)(u_long)pager->pg_handle;
	offset = m->offset + object->paging_offset;
	prot = PROT_READ;	/* XXX should pass in? */
	mapfunc = cdevsw[major(dev)].d_mmap;

	if (mapfunc == NULL || mapfunc == enodev || mapfunc == nullop)
		panic("dev_pager_getpage: no map function");

	paddr = pmap_phys_address((*mapfunc)((dev_t)dev, (int)offset, prot));
#ifdef DIAGNOSTIC
	if (paddr == -1)
		panic("dev_pager_getpage: map function returns error");
#endif
	/*
	 * Replace the passed in page with our own fake page and free
	 * up the original.
	 */
	page = dev_pager_getfake(paddr);
	queue_enter(&((dev_pager_t)pager->pg_data)->devp_pglist,
		    page, vm_page_t, pageq);
	vm_object_lock(object);
	vm_page_lock_queues();
	vm_page_free(m);
	vm_page_unlock_queues();
	s = splhigh();
	vm_page_insert(page, object, offset);
	splx(s);
	PAGE_WAKEUP(m);
	if (offset + PAGE_SIZE > object->size)
		object->size = offset + PAGE_SIZE;	/* XXX anal */
	vm_object_unlock(object);

	return(VM_PAGER_OK);
}

static int
dev_pager_putpage(pager, m, sync)
	vm_pager_t pager;
	vm_page_t m;
	boolean_t sync;
{
#ifdef DEBUG
	if (dpagerdebug & DDB_FOLLOW)
		printf("dev_pager_putpage(%x, %x)\n", pager, m);
#endif
	if (pager == NULL)
		return 0;
	panic("dev_pager_putpage called");
}

static boolean_t
dev_pager_haspage(pager, offset)
	vm_pager_t pager;
	vm_offset_t offset;
{
#ifdef DEBUG
	if (dpagerdebug & DDB_FOLLOW)
		printf("dev_pager_haspage(%x, %x)\n", pager, offset);
#endif
	return(TRUE);
}

static vm_page_t
dev_pager_getfake(paddr)
	vm_offset_t paddr;
{
	vm_page_t m;
	int i;

	if (queue_empty(&dev_pager_fakelist)) {
		m = (vm_page_t)malloc(PAGE_SIZE, M_VMPGDATA, M_WAITOK);
		for (i = PAGE_SIZE / sizeof(*m); i > 0; i--) {
			queue_enter(&dev_pager_fakelist, m, vm_page_t, pageq);
			m++;
		}
	}
	queue_remove_first(&dev_pager_fakelist, m, vm_page_t, pageq);

	m->flags = PG_BUSY | PG_CLEAN | PG_FAKE | PG_FICTITIOUS;

	m->wire_count = 1;
	m->phys_addr = paddr;

	return(m);
}

static void
dev_pager_putfake(m)
	vm_page_t m;
{
#ifdef DIAGNOSTIC
	if (!(m->flags & PG_FICTITIOUS))
		panic("dev_pager_putfake: bad page");
#endif
	queue_enter(&dev_pager_fakelist, m, vm_page_t, pageq);
}
Commit	Line	Data
15637ed4 RG	1	/*
15637ed4 RG	2	* Copyright (c) 1990 University of Utah.
0a8fbd8d DG	3	* Copyright (c) 1991, 1993
0a8fbd8d DG	4	* The Regents of the University of California. All rights reserved.
15637ed4 RG	5	*
	6	* This code is derived from software contributed to Berkeley by
	7	* the Systems Programming Group of the University of Utah Computer
	8	* Science Department.
	9	*
	10	* Redistribution and use in source and binary forms, with or without
	11	* modification, are permitted provided that the following conditions
	12	* are met:
	13	* 1. Redistributions of source code must retain the above copyright
	14	* notice, this list of conditions and the following disclaimer.
	15	* 2. Redistributions in binary form must reproduce the above copyright
	16	* notice, this list of conditions and the following disclaimer in the
	17	* documentation and/or other materials provided with the distribution.
	18	* 3. All advertising materials mentioning features or use of this software
	19	* must display the following acknowledgement:
	20	* This product includes software developed by the University of
	21	* California, Berkeley and its contributors.
	22	* 4. Neither the name of the University nor the names of its contributors
	23	* may be used to endorse or promote products derived from this software
	24	* without specific prior written permission.
	25	*
	26	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	27	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	28	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	29	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	30	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	31	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	32	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	33	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	34	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	35	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	36	* SUCH DAMAGE.
	37	*
0a8fbd8d	38	* @(#)device_pager.c 8.1 (Berkeley) 6/11/93
15637ed4 RG	39	*/
	40
	41	/*
	42	* Page to/from special files.
	43	*/
	44
0a8fbd8d DG	45	#include <sys/param.h>
	46	#include <sys/systm.h>
	47	#include <sys/conf.h>
	48	#include <sys/mman.h>
	49	#include <sys/malloc.h>
15637ed4	50
0a8fbd8d DG	51	#include <vm/vm.h>
	52	#include <vm/vm_kern.h>
	53	#include <vm/vm_page.h>
	54	#include <vm/device_pager.h>
15637ed4	55
3ed7acd6 PR	56	#include "vnode.h"
3ed7acd6 PR	57	#include "specdev.h"
15637ed4	58
0a8fbd8d DG	59	queue_head_t dev_pager_list; /* list of managed devices */
0a8fbd8d DG	60	queue_head_t dev_pager_fakelist; /* list of available vm_page_t's */
15637ed4 RG	61
	62	#ifdef DEBUG
	63	int dpagerdebug = 0;
	64	#define DDB_FOLLOW 0x01
	65	#define DDB_INIT 0x02
	66	#define DDB_ALLOC 0x04
	67	#define DDB_FAIL 0x08
	68	#endif
	69
0a8fbd8d DG	70	static vm_pager_t dev_pager_alloc
	71	__P((caddr_t, vm_size_t, vm_prot_t, vm_offset_t));
	72	static void dev_pager_dealloc __P((vm_pager_t));
	73	static int dev_pager_getpage
	74	__P((vm_pager_t, vm_page_t, boolean_t));
	75	static boolean_t dev_pager_haspage __P((vm_pager_t, vm_offset_t));
	76	static void dev_pager_init __P((void));
	77	static int dev_pager_putpage
	78	__P((vm_pager_t, vm_page_t, boolean_t));
	79	static vm_page_t dev_pager_getfake __P((vm_offset_t));
	80	static void dev_pager_putfake __P((vm_page_t));
	81
	82	struct pagerops devicepagerops = {
	83	dev_pager_init,
	84	dev_pager_alloc,
	85	dev_pager_dealloc,
	86	dev_pager_getpage,
55768178	87	0,
0a8fbd8d	88	dev_pager_putpage,
22c84afa	89	0,
0a8fbd8d DG	90	dev_pager_haspage
	91	};
	92
	93	static void
15637ed4 RG	94	dev_pager_init()
	95	{
	96	#ifdef DEBUG
	97	if (dpagerdebug & DDB_FOLLOW)
	98	printf("dev_pager_init()\n");
	99	#endif
	100	queue_init(&dev_pager_list);
0a8fbd8d	101	queue_init(&dev_pager_fakelist);
15637ed4 RG	102	}
15637ed4 RG	103
0a8fbd8d DG	104	static vm_pager_t
0a8fbd8d DG	105	dev_pager_alloc(handle, size, prot, foff)
15637ed4 RG	106	caddr_t handle;
	107	vm_size_t size;
	108	vm_prot_t prot;
0a8fbd8d	109	vm_offset_t foff;
15637ed4	110	{
2dbd2022	111	dev_t dev;
15637ed4	112	vm_pager_t pager;
0a8fbd8d DG	113	int (*mapfunc)();
	114	vm_object_t object;
	115	dev_pager_t devp;
	116	unsigned int npages, off;
15637ed4 RG	117
	118	#ifdef DEBUG
	119	if (dpagerdebug & DDB_FOLLOW)
0a8fbd8d DG	120	printf("dev_pager_alloc(%x, %x, %x, %x)\n",
0a8fbd8d DG	121	handle, size, prot, foff);
15637ed4	122	#endif
0a8fbd8d	123	#ifdef DIAGNOSTIC
15637ed4 RG	124	/*
	125	* Pageout to device, should never happen.
	126	*/
	127	if (handle == NULL)
	128	panic("dev_pager_alloc called");
0a8fbd8d DG	129	#endif
	130
	131	/*
	132	* Make sure this device can be mapped.
	133	*/
2dbd2022 DG	134	dev = (dev_t)(u_long)handle;
2dbd2022 DG	135	mapfunc = cdevsw[major(dev)].d_mmap;
0a8fbd8d DG	136	if (mapfunc == NULL \|\| mapfunc == enodev \|\| mapfunc == nullop)
	137	return(NULL);
	138
	139	/*
	140	* Offset should be page aligned.
	141	*/
55768178	142	if (foff & (PAGE_SIZE-1))
0a8fbd8d	143	return(NULL);
15637ed4 RG	144
15637ed4 RG	145	/*
0a8fbd8d DG	146	* Check that the specified range of the device allows the
	147	* desired protection.
	148	*
	149	* XXX assumes VM_PROT_* == PROT_*
15637ed4	150	*/
0a8fbd8d DG	151	npages = atop(round_page(size));
	152	for (off = foff; npages--; off += PAGE_SIZE)
	153	if ((*mapfunc)(dev, off, (int)prot) == -1)
	154	return(NULL);
	155
	156	/*
	157	* Look up pager, creating as necessary.
	158	*/
	159	top:
15637ed4 RG	160	pager = vm_pager_lookup(&dev_pager_list, handle);
15637ed4 RG	161	if (pager == NULL) {
15637ed4 RG	162	/*
	163	* Allocate and initialize pager structs
	164	*/
	165	pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
	166	if (pager == NULL)
	167	return(NULL);
	168	devp = (dev_pager_t)malloc(sizeof *devp, M_VMPGDATA, M_WAITOK);
	169	if (devp == NULL) {
	170	free((caddr_t)pager, M_VMPAGER);
	171	return(NULL);
	172	}
15637ed4 RG	173	pager->pg_handle = handle;
	174	pager->pg_ops = &devicepagerops;
	175	pager->pg_type = PG_DEVICE;
	176	pager->pg_data = (caddr_t)devp;
0a8fbd8d	177	queue_init(&devp->devp_pglist);
15637ed4	178	/*
0a8fbd8d	179	* Allocate object and associate it with the pager.
15637ed4	180	*/
0a8fbd8d	181	object = devp->devp_object = vm_object_allocate(0);
15637ed4	182	vm_object_enter(object, pager);
0a8fbd8d	183	vm_object_setpager(object, pager, (vm_offset_t)foff, FALSE);
15637ed4 RG	184	/*
15637ed4 RG	185	* Finally, put it on the managed list so other can find it.
0a8fbd8d DG	186	* First we re-lookup in case someone else beat us to this
	187	* point (due to blocking in the various mallocs). If so,
	188	* we free everything and start over.
15637ed4	189	*/
0a8fbd8d DG	190	if (vm_pager_lookup(&dev_pager_list, handle)) {
	191	free((caddr_t)devp, M_VMPGDATA);
	192	free((caddr_t)pager, M_VMPAGER);
	193	goto top;
	194	}
15637ed4 RG	195	queue_enter(&dev_pager_list, pager, vm_pager_t, pg_list);
15637ed4 RG	196	#ifdef DEBUG
0a8fbd8d DG	197	if (dpagerdebug & DDB_ALLOC) {
	198	printf("dev_pager_alloc: pager %x devp %x object %x\n",
	199	pager, devp, object);
	200	vm_object_print(object, FALSE);
	201	}
15637ed4 RG	202	#endif
	203	} else {
	204	/*
	205	* vm_object_lookup() gains a reference and also
	206	* removes the object from the cache.
	207	*/
0a8fbd8d DG	208	object = vm_object_lookup(pager);
0a8fbd8d DG	209	#ifdef DIAGNOSTIC
15637ed4	210	devp = (dev_pager_t)pager->pg_data;
0a8fbd8d	211	if (object != devp->devp_object)
15637ed4	212	panic("dev_pager_setup: bad object");
15637ed4	213	#endif
0a8fbd8d	214	}
15637ed4	215	return(pager);
15637ed4 RG	216	}
15637ed4 RG	217
0a8fbd8d	218	static void
15637ed4 RG	219	dev_pager_dealloc(pager)
	220	vm_pager_t pager;
	221	{
0a8fbd8d DG	222	dev_pager_t devp;
	223	vm_object_t object;
	224	vm_page_t m;
15637ed4 RG	225
	226	#ifdef DEBUG
	227	if (dpagerdebug & DDB_FOLLOW)
	228	printf("dev_pager_dealloc(%x)\n", pager);
	229	#endif
	230	queue_remove(&dev_pager_list, pager, vm_pager_t, pg_list);
0a8fbd8d DG	231	/*
	232	* Get the object.
	233	* Note: cannot use vm_object_lookup since object has already
	234	* been removed from the hash chain.
	235	*/
	236	devp = (dev_pager_t)pager->pg_data;
15637ed4 RG	237	object = devp->devp_object;
	238	#ifdef DEBUG
	239	if (dpagerdebug & DDB_ALLOC)
0a8fbd8d	240	printf("dev_pager_dealloc: devp %x object %x\n", devp, object);
15637ed4	241	#endif
0a8fbd8d DG	242	/*
	243	* Free up our fake pages.
	244	*/
	245	while (!queue_empty(&devp->devp_pglist)) {
	246	queue_remove_first(&devp->devp_pglist, m, vm_page_t, pageq);
	247	dev_pager_putfake(m);
	248	}
15637ed4 RG	249	free((caddr_t)devp, M_VMPGDATA);
15637ed4 RG	250	free((caddr_t)pager, M_VMPAGER);
15637ed4 RG	251	}
15637ed4 RG	252
0a8fbd8d	253	static int
15637ed4 RG	254	dev_pager_getpage(pager, m, sync)
	255	vm_pager_t pager;
	256	vm_page_t m;
	257	boolean_t sync;
	258	{
0a8fbd8d DG	259	register vm_object_t object;
	260	vm_offset_t offset, paddr;
	261	vm_page_t page;
2dbd2022	262	dev_t dev;
55768178	263	int s;
0a8fbd8d DG	264	int (*mapfunc)(), prot;
0a8fbd8d DG	265
15637ed4 RG	266	#ifdef DEBUG
	267	if (dpagerdebug & DDB_FOLLOW)
	268	printf("dev_pager_getpage(%x, %x)\n", pager, m);
	269	#endif
0a8fbd8d DG	270
0a8fbd8d DG	271	object = m->object;
2dbd2022	272	dev = (dev_t)(u_long)pager->pg_handle;
0a8fbd8d DG	273	offset = m->offset + object->paging_offset;
0a8fbd8d DG	274	prot = PROT_READ; /* XXX should pass in? */
2dbd2022	275	mapfunc = cdevsw[major(dev)].d_mmap;
9f6fb340	276
0a8fbd8d DG	277	if (mapfunc == NULL \|\| mapfunc == enodev \|\| mapfunc == nullop)
0a8fbd8d DG	278	panic("dev_pager_getpage: no map function");
9f6fb340 DG	279
9f6fb340 DG	280	paddr = pmap_phys_address((*mapfunc)((dev_t)dev, (int)offset, prot));
0a8fbd8d DG	281	#ifdef DIAGNOSTIC
	282	if (paddr == -1)
	283	panic("dev_pager_getpage: map function returns error");
	284	#endif
	285	/*
	286	* Replace the passed in page with our own fake page and free
	287	* up the original.
	288	*/
	289	page = dev_pager_getfake(paddr);
	290	queue_enter(&((dev_pager_t)pager->pg_data)->devp_pglist,
	291	page, vm_page_t, pageq);
	292	vm_object_lock(object);
	293	vm_page_lock_queues();
	294	vm_page_free(m);
	295	vm_page_unlock_queues();
55768178	296	s = splhigh();
0a8fbd8d	297	vm_page_insert(page, object, offset);
55768178	298	splx(s);
0a8fbd8d DG	299	PAGE_WAKEUP(m);
	300	if (offset + PAGE_SIZE > object->size)
	301	object->size = offset + PAGE_SIZE; /* XXX anal */
	302	vm_object_unlock(object);
	303
	304	return(VM_PAGER_OK);
15637ed4 RG	305	}
15637ed4 RG	306
0a8fbd8d	307	static int
15637ed4 RG	308	dev_pager_putpage(pager, m, sync)
	309	vm_pager_t pager;
	310	vm_page_t m;
	311	boolean_t sync;
	312	{
	313	#ifdef DEBUG
	314	if (dpagerdebug & DDB_FOLLOW)
	315	printf("dev_pager_putpage(%x, %x)\n", pager, m);
	316	#endif
	317	if (pager == NULL)
4c45483e	318	return 0;
15637ed4 RG	319	panic("dev_pager_putpage called");
	320	}
	321
0a8fbd8d	322	static boolean_t
15637ed4 RG	323	dev_pager_haspage(pager, offset)
	324	vm_pager_t pager;
	325	vm_offset_t offset;
	326	{
	327	#ifdef DEBUG
	328	if (dpagerdebug & DDB_FOLLOW)
	329	printf("dev_pager_haspage(%x, %x)\n", pager, offset);
	330	#endif
	331	return(TRUE);
	332	}
0a8fbd8d DG	333
	334	static vm_page_t
	335	dev_pager_getfake(paddr)
	336	vm_offset_t paddr;
	337	{
	338	vm_page_t m;
	339	int i;
	340
	341	if (queue_empty(&dev_pager_fakelist)) {
	342	m = (vm_page_t)malloc(PAGE_SIZE, M_VMPGDATA, M_WAITOK);
	343	for (i = PAGE_SIZE / sizeof(*m); i > 0; i--) {
	344	queue_enter(&dev_pager_fakelist, m, vm_page_t, pageq);
	345	m++;
	346	}
	347	}
	348	queue_remove_first(&dev_pager_fakelist, m, vm_page_t, pageq);
9f6fb340	349
0a8fbd8d	350	m->flags = PG_BUSY \| PG_CLEAN \| PG_FAKE \| PG_FICTITIOUS;
9f6fb340	351
0a8fbd8d	352	m->wire_count = 1;
9f6fb340 DG	353	m->phys_addr = paddr;
9f6fb340 DG	354
0a8fbd8d DG	355	return(m);
	356	}
	357
	358	static void
	359	dev_pager_putfake(m)
	360	vm_page_t m;
	361	{
	362	#ifdef DIAGNOSTIC
0a8fbd8d	363	if (!(m->flags & PG_FICTITIOUS))
0a8fbd8d DG	364	panic("dev_pager_putfake: bad page");
	365	#endif
	366	queue_enter(&dev_pager_fakelist, m, vm_page_t, pageq);
	367	}