bsd/vm/vm_pager.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Mach Operating System
  25  * Copyright (c) 1987 Carnegie-Mellon University
  26  * All rights reserved.  The CMU software License Agreement specifies
  27  * the terms and conditions for use and redistribution.
  28  */
  29 /*
  30  *      File:   vm_pager.h
  31  *      Author: Avadis Tevanian, Jr., Michael Wayne Young
  32  *
  33  *      Copyright (C) 1986, Avadis Tevanian, Jr., Michael Wayne Young
  34  *      Copyright (C) 1985, Avadis Tevanian, Jr., Michael Wayne Young
  35  *
  36  *      Pager routine interface definition
  37  */
  38
  39 #ifndef _VM_PAGER_
  40 #define _VM_PAGER_
  41
  42 #include <mach/boolean.h>
  43
  44 struct  pager_struct {
  45         boolean_t       is_device;
  46 };
  47 typedef struct pager_struct     *vm_pager_t;
  48 #define vm_pager_null           ((vm_pager_t) 0)
  49
  50 #define PAGER_SUCCESS           0  /* page read or written */
  51 #define PAGER_ABSENT            1  /* pager does not have page */
  52 #define PAGER_ERROR             2  /* pager unable to read or write page */
  53
  54 #ifdef  KERNEL
  55 typedef int             pager_return_t;
  56
  57 extern vm_pager_t               vm_pager_allocate(void);
  58 extern void                             vm_pager_deallocate(void);
  59 extern pager_return_t   vm_pager_get(void);
  60 extern pager_return_t   vm_pager_put(void);
  61 extern boolean_t                vm_pager_has_page(void);
  62 #endif  /* KERNEL */
  63
  64 #endif  /* _VM_PAGER_ */