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 1.9 2006/12/28 21:24:02 dillon Exp $
  41  */
  42
  43 /*
  44  * Pager routine interface definition.
  45  */
  46
  47 #ifndef _VM_VM_PAGER_H_
  48 #define _VM_VM_PAGER_H_
  49
  50 #ifndef _SYS_QUEUE_H_
  51 #include <sys/queue.h>
  52 #endif
  53 #ifndef _VM_VM_PAGE_H_
  54 #include <vm/vm_page.h>
  55 #endif
  56 #ifndef _VM_VM_OBJECT_H_
  57 #include <vm/vm_object.h>
  58 #endif
  59
  60 TAILQ_HEAD(pagerlst, vm_object);
  61
  62 struct buf;
  63 struct bio;
  64
  65 struct pagerops {
  66         void (*pgo_init) (void);                /* Initialize pager. */
  67         vm_object_t (*pgo_alloc) (void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);       /* Allocate pager. */
  68         void (*pgo_dealloc) (vm_object_t);      /* Disassociate. */
  69         int (*pgo_getpages) (vm_object_t, vm_page_t *, int, int);       /* Get (read) page. */
  70         void (*pgo_putpages) (vm_object_t, vm_page_t *, int, int, int *); /* Put (write) page. */
  71         boolean_t (*pgo_haspage) (vm_object_t, vm_pindex_t, int *, int *); /* Does pager have page? */
  72         void (*pgo_pageunswapped) (vm_page_t);
  73         void (*pgo_strategy) (vm_object_t, struct bio *);
  74 };
  75
  76 /*
  77  * get/put return values
  78  * OK    operation was successful
  79  * BAD   specified data was out of the accepted range
  80  * FAIL  specified data was in range, but doesn't exist
  81  * PEND  operations was initiated but not completed
  82  * ERROR error while accessing data that is in range and exists
  83  * AGAIN temporary resource shortage prevented operation from happening
  84  */
  85 #define VM_PAGER_OK     0
  86 #define VM_PAGER_BAD    1
  87 #define VM_PAGER_FAIL   2
  88 #define VM_PAGER_PEND   3
  89 #define VM_PAGER_ERROR  4
  90 #define VM_PAGER_AGAIN  5
  91
  92 #define VM_PAGER_PUT_SYNC               0x0001
  93 #define VM_PAGER_PUT_INVAL              0x0002
  94 #define VM_PAGER_IGNORE_CLEANCHK        0x0004
  95 #define VM_PAGER_CLUSTER_OK             0x0008
  96
  97 #ifdef _KERNEL
  98
  99 #ifdef MALLOC_DECLARE
 100 MALLOC_DECLARE(M_VMPGDATA);
 101 #endif
 102
 103 struct vnode;
 104
 105 extern struct vm_map pager_map;
 106 extern int pager_map_size;
 107 extern struct pagerops *pagertab[];
 108
 109 vm_object_t vm_pager_allocate (objtype_t, void *, off_t, vm_prot_t, off_t);
 110 void vm_pager_bufferinit (void);
 111 void vm_pager_deallocate (vm_object_t);
 112 static __inline int vm_pager_get_pages (vm_object_t, vm_page_t *, int, int);
 113 static __inline boolean_t vm_pager_has_page (vm_object_t, vm_pindex_t, int *, int *);
 114 void vm_pager_init (void);
 115 vm_object_t vm_pager_object_lookup (struct pagerlst *, void *);
 116 void vm_pager_sync (void);
 117 void vm_pager_strategy (vm_object_t object, struct bio *bio);
 118 struct buf *getchainbuf(struct buf *bp, struct vnode *vp, int flags);
 119 void flushchainbuf(struct buf *nbp);
 120 void waitchainbuf(struct buf *bp, int count, int done);
 121 void autochaindone(struct buf *bp);
 122
 123 /*
 124  *      vm_page_get_pages:
 125  *
 126  *      Retrieve pages from the VM system in order to map them into an object
 127  *      ( or into VM space somewhere ).  If the pagein was successful, we
 128  *      must fully validate it.
 129  */
 130
 131 static __inline int
 132 vm_pager_get_pages(
 133         vm_object_t object,
 134         vm_page_t *m,
 135         int count,
 136         int reqpage
 137 ) {
 138         int r;
 139
 140         r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
 141         if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
 142                 vm_page_zero_invalid(m[reqpage], TRUE);
 143         }
 144         return(r);
 145 }
 146
 147 static __inline void
 148 vm_pager_put_pages(
 149         vm_object_t object,
 150         vm_page_t *m,
 151         int count,
 152         int flags,
 153         int *rtvals
 154 ) {
 155         (*pagertab[object->type]->pgo_putpages)
 156             (object, m, count, flags, rtvals);
 157 }
 158
 159 /*
 160  *      vm_pager_haspage
 161  *
 162  *      Check to see if an object's pager has the requested page.  The
 163  *      object's pager will also set before and after to give the caller
 164  *      some idea of the number of pages before and after the requested
 165  *      page can be I/O'd efficiently.
 166  *
 167  *      This routine does not have to be called at any particular spl.
 168  */
 169
 170 static __inline boolean_t
 171 vm_pager_has_page(
 172         vm_object_t object,
 173         vm_pindex_t offset,
 174         int *before,
 175         int *after
 176 ) {
 177         return ((*pagertab[object->type]->pgo_haspage) (object, offset, before, after));
 178 }
 179
 180 /*
 181  *      vm_pager_page_unswapped
 182  *
 183  *      called at splvm() to destroy swap associated with the page.
 184  *
 185  *      This function may not block.
 186  */
 187
 188 static __inline void
 189 vm_pager_page_unswapped(vm_page_t m)
 190 {
 191         if (pagertab[m->object->type]->pgo_pageunswapped)
 192                 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
 193 }
 194
 195 #endif
 196
 197 #endif                          /* _VM_VM_PAGER_H_ */