FreeBSD/Linux Kernel Cross Reference
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 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)vm_pager.h 8.4 (Berkeley) 1/12/94
35 * $FreeBSD$
36 */
37
38 /*
39 * Pager routine interface definition.
40 */
41
42 #ifndef _VM_PAGER_
43 #define _VM_PAGER_
44
45 #include <sys/queue.h>
46
47 TAILQ_HEAD(pagerlst, vm_object);
48
49 typedef void pgo_init_t(void);
50 typedef vm_object_t pgo_alloc_t(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t,
51 struct ucred *);
52 typedef void pgo_dealloc_t(vm_object_t);
53 typedef int pgo_getpages_t(vm_object_t, vm_page_t *, int, int);
54 typedef void pgo_putpages_t(vm_object_t, vm_page_t *, int, int, int *);
55 typedef boolean_t pgo_haspage_t(vm_object_t, vm_pindex_t, int *, int *);
56 typedef void pgo_pageunswapped_t(vm_page_t);
57
58 struct pagerops {
59 pgo_init_t *pgo_init; /* Initialize pager. */
60 pgo_alloc_t *pgo_alloc; /* Allocate pager. */
61 pgo_dealloc_t *pgo_dealloc; /* Disassociate. */
62 pgo_getpages_t *pgo_getpages; /* Get (read) page. */
63 pgo_putpages_t *pgo_putpages; /* Put (write) page. */
64 pgo_haspage_t *pgo_haspage; /* Does pager have page? */
65 pgo_pageunswapped_t *pgo_pageunswapped;
66 };
67
68 extern struct pagerops defaultpagerops;
69 extern struct pagerops swappagerops;
70 extern struct pagerops vnodepagerops;
71 extern struct pagerops devicepagerops;
72 extern struct pagerops physpagerops;
73 extern struct pagerops sgpagerops;
74 extern struct pagerops mgtdevicepagerops;
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_CLUSTER_OK 0x0008
95
96 #ifdef _KERNEL
97
98 extern struct pagerops *pagertab[];
99 extern struct mtx_padalign pbuf_mtx;
100
101 vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t,
102 vm_ooffset_t, struct ucred *);
103 void vm_pager_bufferinit(void);
104 void vm_pager_deallocate(vm_object_t);
105 static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
106 void vm_pager_init(void);
107 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
108
109 /*
110 * vm_page_get_pages:
111 *
112 * Retrieve pages from the VM system in order to map them into an object
113 * ( or into VM space somewhere ). If the pagein was successful, we
114 * must fully validate it.
115 */
116 static __inline int
117 vm_pager_get_pages(
118 vm_object_t object,
119 vm_page_t *m,
120 int count,
121 int reqpage
122 ) {
123 int r;
124
125 VM_OBJECT_ASSERT_WLOCKED(object);
126 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
127 if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
128 vm_page_zero_invalid(m[reqpage], TRUE);
129 }
130 return (r);
131 }
132
133 static __inline void
134 vm_pager_put_pages(
135 vm_object_t object,
136 vm_page_t *m,
137 int count,
138 int flags,
139 int *rtvals
140 ) {
141
142 VM_OBJECT_ASSERT_WLOCKED(object);
143 (*pagertab[object->type]->pgo_putpages)
144 (object, m, count, flags, rtvals);
145 }
146
147 /*
148 * vm_pager_haspage
149 *
150 * Check to see if an object's pager has the requested page. The
151 * object's pager will also set before and after to give the caller
152 * some idea of the number of pages before and after the requested
153 * page can be I/O'd efficiently.
154 *
155 * The object must be locked.
156 */
157 static __inline boolean_t
158 vm_pager_has_page(
159 vm_object_t object,
160 vm_pindex_t offset,
161 int *before,
162 int *after
163 ) {
164 boolean_t ret;
165
166 VM_OBJECT_ASSERT_WLOCKED(object);
167 ret = (*pagertab[object->type]->pgo_haspage)
168 (object, offset, before, after);
169 return (ret);
170 }
171
172 /*
173 * vm_pager_page_unswapped
174 *
175 * Destroy swap associated with the page.
176 *
177 * The object containing the page must be locked.
178 * This function may not block.
179 *
180 * XXX: A much better name would be "vm_pager_page_dirtied()"
181 * XXX: It is not obvious if this could be profitably used by any
182 * XXX: pagers besides the swap_pager or if it should even be a
183 * XXX: generic pager_op in the first place.
184 */
185 static __inline void
186 vm_pager_page_unswapped(vm_page_t m)
187 {
188
189 VM_OBJECT_ASSERT_LOCKED(m->object);
190 if (pagertab[m->object->type]->pgo_pageunswapped)
191 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
192 }
193
194 struct cdev_pager_ops {
195 int (*cdev_pg_fault)(vm_object_t vm_obj, vm_ooffset_t offset,
196 int prot, vm_page_t *mres);
197 int (*cdev_pg_ctor)(void *handle, vm_ooffset_t size, vm_prot_t prot,
198 vm_ooffset_t foff, struct ucred *cred, u_short *color);
199 void (*cdev_pg_dtor)(void *handle);
200 };
201
202 vm_object_t cdev_pager_allocate(void *handle, enum obj_type tp,
203 struct cdev_pager_ops *ops, vm_ooffset_t size, vm_prot_t prot,
204 vm_ooffset_t foff, struct ucred *cred);
205 vm_object_t cdev_pager_lookup(void *handle);
206 void cdev_pager_free_page(vm_object_t object, vm_page_t m);
207
208 #endif /* _KERNEL */
209 #endif /* _VM_PAGER_ */
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