sys/vm/vm_pager.h

   1 /*
   2  * Copyright (c) 1990 University of Utah.
   3  * Copyright (c) 1991, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   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  *
  38  *      @(#)vm_pager.h  8.4 (Berkeley) 1/12/94
  39  * $FreeBSD: src/sys/vm/vm_pager.h,v 1.24.2.2 2002/12/31 09:34:51 dillon Exp $
  40  * $DragonFly: src/sys/vm/vm_pager.h,v 1.5 2005/01/23 13:24:20 joerg Exp $
  41  */
  42
  43 /*
  44  * Pager routine interface definition.
  45  */
  46
  47 #ifndef _VM_PAGER_
  48 #define _VM_PAGER_
  49
  50 #include <sys/queue.h>
  51
  52 TAILQ_HEAD(pagerlst, vm_object);
  53
  54 struct buf;
  55
  56 struct pagerops {
  57         void (*pgo_init) (void);                /* Initialize pager. */
  58         vm_object_t (*pgo_alloc) (void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);       /* Allocate pager. */
  59         void (*pgo_dealloc) (vm_object_t);      /* Disassociate. */
  60         int (*pgo_getpages) (vm_object_t, vm_page_t *, int, int);       /* Get (read) page. */
  61         void (*pgo_putpages) (vm_object_t, vm_page_t *, int, int, int *); /* Put (write) page. */
  62         boolean_t (*pgo_haspage) (vm_object_t, vm_pindex_t, int *, int *); /* Does pager have page? */
  63         void (*pgo_pageunswapped) (vm_page_t);
  64         void (*pgo_strategy) (vm_object_t, struct buf *);
  65 };
  66
  67 /*
  68  * get/put return values
  69  * OK    operation was successful
  70  * BAD   specified data was out of the accepted range
  71  * FAIL  specified data was in range, but doesn't exist
  72  * PEND  operations was initiated but not completed
  73  * ERROR error while accessing data that is in range and exists
  74  * AGAIN temporary resource shortage prevented operation from happening
  75  */
  76 #define VM_PAGER_OK     0
  77 #define VM_PAGER_BAD    1
  78 #define VM_PAGER_FAIL   2
  79 #define VM_PAGER_PEND   3
  80 #define VM_PAGER_ERROR  4
  81 #define VM_PAGER_AGAIN  5
  82
  83 #define VM_PAGER_PUT_SYNC               0x0001
  84 #define VM_PAGER_PUT_INVAL              0x0002
  85 #define VM_PAGER_IGNORE_CLEANCHK        0x0004
  86 #define VM_PAGER_CLUSTER_OK             0x0008
  87
  88 #ifdef _KERNEL
  89
  90 #ifdef MALLOC_DECLARE
  91 MALLOC_DECLARE(M_VMPGDATA);
  92 #endif
  93
  94 struct vnode;
  95
  96 extern vm_map_t pager_map;
  97 extern int pager_map_size;
  98 extern struct pagerops *pagertab[];
  99
 100 vm_object_t vm_pager_allocate (objtype_t, void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
 101 void vm_pager_bufferinit (void);
 102 void vm_pager_deallocate (vm_object_t);
 103 static __inline int vm_pager_get_pages (vm_object_t, vm_page_t *, int, int);
 104 static __inline boolean_t vm_pager_has_page (vm_object_t, vm_pindex_t, int *, int *);
 105 void vm_pager_init (void);
 106 vm_object_t vm_pager_object_lookup (struct pagerlst *, void *);
 107 void vm_pager_sync (void);
 108 void vm_pager_strategy (vm_object_t object, struct buf *bp);
 109 struct buf *getchainbuf(struct buf *bp, struct vnode *vp, int flags);
 110 void flushchainbuf(struct buf *nbp);
 111 void waitchainbuf(struct buf *bp, int count, int done);
 112 void autochaindone(struct buf *bp);
 113
 114 /*
 115  *      vm_page_get_pages:
 116  *
 117  *      Retrieve pages from the VM system in order to map them into an object
 118  *      ( or into VM space somewhere ).  If the pagein was successful, we
 119  *      must fully validate it.
 120  */
 121
 122 static __inline int
 123 vm_pager_get_pages(
 124         vm_object_t object,
 125         vm_page_t *m,
 126         int count,
 127         int reqpage
 128 ) {
 129         int r;
 130
 131         r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
 132         if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
 133                 vm_page_zero_invalid(m[reqpage], TRUE);
 134         }
 135         return(r);
 136 }
 137
 138 static __inline void
 139 vm_pager_put_pages(
 140         vm_object_t object,
 141         vm_page_t *m,
 142         int count,
 143         int flags,
 144         int *rtvals
 145 ) {
 146         (*pagertab[object->type]->pgo_putpages)
 147             (object, m, count, flags, rtvals);
 148 }
 149
 150 /*
 151  *      vm_pager_haspage
 152  *
 153  *      Check to see if an object's pager has the requested page.  The
 154  *      object's pager will also set before and after to give the caller
 155  *      some idea of the number of pages before and after the requested
 156  *      page can be I/O'd efficiently.
 157  *
 158  *      This routine does not have to be called at any particular spl.
 159  */
 160
 161 static __inline boolean_t
 162 vm_pager_has_page(
 163         vm_object_t object,
 164         vm_pindex_t offset,
 165         int *before,
 166         int *after
 167 ) {
 168         return ((*pagertab[object->type]->pgo_haspage) (object, offset, before, after));
 169 }
 170
 171 /*
 172  *      vm_pager_page_unswapped
 173  *
 174  *      called at splvm() to destroy swap associated with the page.
 175  *
 176  *      This function may not block.
 177  */
 178
 179 static __inline void
 180 vm_pager_page_unswapped(vm_page_t m)
 181 {
 182         if (pagertab[m->object->type]->pgo_pageunswapped)
 183                 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
 184 }
 185
 186 #endif
 187
 188 #endif                          /* _VM_PAGER_ */