FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_pager.h
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990 University of Utah.
5 * Copyright (c) 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)vm_pager.h 8.4 (Berkeley) 1/12/94
37 * $FreeBSD$
38 */
39
40 /*
41 * Pager routine interface definition.
42 */
43
44 #ifndef _VM_PAGER_
45 #define _VM_PAGER_
46
47 #include <sys/queue.h>
48
49 TAILQ_HEAD(pagerlst, vm_object);
50
51 typedef void pgo_init_t(void);
52 typedef vm_object_t pgo_alloc_t(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t,
53 struct ucred *);
54 typedef void pgo_dealloc_t(vm_object_t);
55 typedef int pgo_getpages_t(vm_object_t, vm_page_t *, int, int *, int *);
56 typedef void pgo_getpages_iodone_t(void *, vm_page_t *, int, int);
57 typedef int pgo_getpages_async_t(vm_object_t, vm_page_t *, int, int *, int *,
58 pgo_getpages_iodone_t, void *);
59 typedef void pgo_putpages_t(vm_object_t, vm_page_t *, int, int, int *);
60 typedef boolean_t pgo_haspage_t(vm_object_t, vm_pindex_t, int *, int *);
61 typedef int pgo_populate_t(vm_object_t, vm_pindex_t, int, vm_prot_t,
62 vm_pindex_t *, vm_pindex_t *);
63 typedef void pgo_pageunswapped_t(vm_page_t);
64 typedef void pgo_writecount_t(vm_object_t, vm_offset_t, vm_offset_t);
65
66 struct pagerops {
67 pgo_init_t *pgo_init; /* Initialize pager. */
68 pgo_alloc_t *pgo_alloc; /* Allocate pager. */
69 pgo_dealloc_t *pgo_dealloc; /* Disassociate. */
70 pgo_getpages_t *pgo_getpages; /* Get (read) page. */
71 pgo_getpages_async_t *pgo_getpages_async; /* Get page asyncly. */
72 pgo_putpages_t *pgo_putpages; /* Put (write) page. */
73 pgo_haspage_t *pgo_haspage; /* Query page. */
74 pgo_populate_t *pgo_populate; /* Bulk spec pagein. */
75 pgo_pageunswapped_t *pgo_pageunswapped;
76 /* Operations for specialized writecount handling */
77 pgo_writecount_t *pgo_update_writecount;
78 pgo_writecount_t *pgo_release_writecount;
79 };
80
81 extern struct pagerops defaultpagerops;
82 extern struct pagerops swappagerops;
83 extern struct pagerops vnodepagerops;
84 extern struct pagerops devicepagerops;
85 extern struct pagerops physpagerops;
86 extern struct pagerops sgpagerops;
87 extern struct pagerops mgtdevicepagerops;
88
89 /*
90 * get/put return values
91 * OK operation was successful
92 * BAD specified data was out of the accepted range
93 * FAIL specified data was in range, but doesn't exist
94 * PEND operations was initiated but not completed
95 * ERROR error while accessing data that is in range and exists
96 * AGAIN temporary resource shortage prevented operation from happening
97 */
98 #define VM_PAGER_OK 0
99 #define VM_PAGER_BAD 1
100 #define VM_PAGER_FAIL 2
101 #define VM_PAGER_PEND 3
102 #define VM_PAGER_ERROR 4
103 #define VM_PAGER_AGAIN 5
104
105 #define VM_PAGER_PUT_SYNC 0x0001
106 #define VM_PAGER_PUT_INVAL 0x0002
107 #define VM_PAGER_PUT_NOREUSE 0x0004
108 #define VM_PAGER_CLUSTER_OK 0x0008
109
110 #ifdef _KERNEL
111
112 extern struct pagerops *pagertab[];
113 extern struct mtx_padalign pbuf_mtx;
114
115 vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t,
116 vm_ooffset_t, struct ucred *);
117 void vm_pager_bufferinit(void);
118 void vm_pager_deallocate(vm_object_t);
119 int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int *, int *);
120 int vm_pager_get_pages_async(vm_object_t, vm_page_t *, int, int *, int *,
121 pgo_getpages_iodone_t, void *);
122 void vm_pager_init(void);
123 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
124
125 static __inline void
126 vm_pager_put_pages(
127 vm_object_t object,
128 vm_page_t *m,
129 int count,
130 int flags,
131 int *rtvals
132 ) {
133
134 VM_OBJECT_ASSERT_WLOCKED(object);
135 (*pagertab[object->type]->pgo_putpages)
136 (object, m, count, flags, rtvals);
137 }
138
139 /*
140 * vm_pager_haspage
141 *
142 * Check to see if an object's pager has the requested page. The
143 * object's pager will also set before and after to give the caller
144 * some idea of the number of pages before and after the requested
145 * page can be I/O'd efficiently.
146 *
147 * The object must be locked.
148 */
149 static __inline boolean_t
150 vm_pager_has_page(
151 vm_object_t object,
152 vm_pindex_t offset,
153 int *before,
154 int *after
155 ) {
156 boolean_t ret;
157
158 VM_OBJECT_ASSERT_WLOCKED(object);
159 ret = (*pagertab[object->type]->pgo_haspage)
160 (object, offset, before, after);
161 return (ret);
162 }
163
164 static __inline int
165 vm_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type,
166 vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
167 {
168
169 MPASS((object->flags & OBJ_POPULATE) != 0);
170 MPASS(pidx < object->size);
171 MPASS(object->paging_in_progress > 0);
172 return ((*pagertab[object->type]->pgo_populate)(object, pidx,
173 fault_type, max_prot, first, last));
174 }
175
176
177 /*
178 * vm_pager_page_unswapped
179 *
180 * Destroy swap associated with the page.
181 *
182 * The object containing the page must be locked.
183 * This function may not block.
184 *
185 * XXX: A much better name would be "vm_pager_page_dirtied()"
186 * XXX: It is not obvious if this could be profitably used by any
187 * XXX: pagers besides the swap_pager or if it should even be a
188 * XXX: generic pager_op in the first place.
189 */
190 static __inline void
191 vm_pager_page_unswapped(vm_page_t m)
192 {
193
194 VM_OBJECT_ASSERT_LOCKED(m->object);
195 if (pagertab[m->object->type]->pgo_pageunswapped)
196 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
197 }
198
199 static __inline void
200 vm_pager_update_writecount(vm_object_t object, vm_offset_t start,
201 vm_offset_t end)
202 {
203
204 if (pagertab[object->type]->pgo_update_writecount)
205 pagertab[object->type]->pgo_update_writecount(object, start,
206 end);
207 }
208
209 static __inline void
210 vm_pager_release_writecount(vm_object_t object, vm_offset_t start,
211 vm_offset_t end)
212 {
213
214 if (pagertab[object->type]->pgo_release_writecount)
215 pagertab[object->type]->pgo_release_writecount(object, start,
216 end);
217 }
218
219 struct cdev_pager_ops {
220 int (*cdev_pg_fault)(vm_object_t vm_obj, vm_ooffset_t offset,
221 int prot, vm_page_t *mres);
222 int (*cdev_pg_populate)(vm_object_t vm_obj, vm_pindex_t pidx,
223 int fault_type, vm_prot_t max_prot, vm_pindex_t *first,
224 vm_pindex_t *last);
225 int (*cdev_pg_ctor)(void *handle, vm_ooffset_t size, vm_prot_t prot,
226 vm_ooffset_t foff, struct ucred *cred, u_short *color);
227 void (*cdev_pg_dtor)(void *handle);
228 };
229
230 vm_object_t cdev_pager_allocate(void *handle, enum obj_type tp,
231 struct cdev_pager_ops *ops, vm_ooffset_t size, vm_prot_t prot,
232 vm_ooffset_t foff, struct ucred *cred);
233 vm_object_t cdev_pager_lookup(void *handle);
234 void cdev_pager_free_page(vm_object_t object, vm_page_t m);
235
236 struct phys_pager_ops {
237 int (*phys_pg_getpages)(vm_object_t vm_obj, vm_page_t *m, int count,
238 int *rbehind, int *rahead);
239 int (*phys_pg_populate)(vm_object_t vm_obj, vm_pindex_t pidx,
240 int fault_type, vm_prot_t max_prot, vm_pindex_t *first,
241 vm_pindex_t *last);
242 boolean_t (*phys_pg_haspage)(vm_object_t obj, vm_pindex_t pindex,
243 int *before, int *after);
244 void (*phys_pg_ctor)(vm_object_t vm_obj, vm_prot_t prot,
245 vm_ooffset_t foff, struct ucred *cred);
246 void (*phys_pg_dtor)(vm_object_t vm_obj);
247 };
248 extern struct phys_pager_ops default_phys_pg_ops;
249 vm_object_t phys_pager_allocate(void *handle, struct phys_pager_ops *ops,
250 void *data, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff,
251 struct ucred *cred);
252
253 #endif /* _KERNEL */
254 #endif /* _VM_PAGER_ */
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