xref: /freebsd/sys/vm/vm_pager.h (revision 7661de35d15f582ab33e3bd6b8d909601557e436)
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 static __inline boolean_t vm_pager_has_page(vm_object_t, vm_pindex_t, int *, int *);
107 void vm_pager_init(void);
108 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
109 
110 /*
111  *	vm_page_get_pages:
112  *
113  *	Retrieve pages from the VM system in order to map them into an object
114  *	( or into VM space somewhere ).  If the pagein was successful, we
115  *	must fully validate it.
116  */
117 static __inline int
118 vm_pager_get_pages(
119 	vm_object_t object,
120 	vm_page_t *m,
121 	int count,
122 	int reqpage
123 ) {
124 	int r;
125 
126 	VM_OBJECT_ASSERT_WLOCKED(object);
127 	r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
128 	if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
129 		vm_page_zero_invalid(m[reqpage], TRUE);
130 	}
131 	return (r);
132 }
133 
134 static __inline void
135 vm_pager_put_pages(
136 	vm_object_t object,
137 	vm_page_t *m,
138 	int count,
139 	int flags,
140 	int *rtvals
141 ) {
142 
143 	VM_OBJECT_ASSERT_WLOCKED(object);
144 	(*pagertab[object->type]->pgo_putpages)
145 	    (object, m, count, flags, rtvals);
146 }
147 
148 /*
149  *	vm_pager_haspage
150  *
151  *	Check to see if an object's pager has the requested page.  The
152  *	object's pager will also set before and after to give the caller
153  *	some idea of the number of pages before and after the requested
154  *	page can be I/O'd efficiently.
155  *
156  *	The object must be locked.
157  */
158 static __inline boolean_t
159 vm_pager_has_page(
160 	vm_object_t object,
161 	vm_pindex_t offset,
162 	int *before,
163 	int *after
164 ) {
165 	boolean_t ret;
166 
167 	VM_OBJECT_ASSERT_WLOCKED(object);
168 	ret = (*pagertab[object->type]->pgo_haspage)
169 	    (object, offset, before, after);
170 	return (ret);
171 }
172 
173 /*
174  *      vm_pager_page_unswapped
175  *
176  *	Destroy swap associated with the page.
177  *
178  *	The object containing the page must be locked.
179  *      This function may not block.
180  *
181  *	XXX: A much better name would be "vm_pager_page_dirtied()"
182  *	XXX: It is not obvious if this could be profitably used by any
183  *	XXX: pagers besides the swap_pager or if it should even be a
184  *	XXX: generic pager_op in the first place.
185  */
186 static __inline void
187 vm_pager_page_unswapped(vm_page_t m)
188 {
189 
190 	VM_OBJECT_ASSERT_WLOCKED(m->object);
191 	if (pagertab[m->object->type]->pgo_pageunswapped)
192 		(*pagertab[m->object->type]->pgo_pageunswapped)(m);
193 }
194 
195 struct cdev_pager_ops {
196 	int (*cdev_pg_fault)(vm_object_t vm_obj, vm_ooffset_t offset,
197 	    int prot, vm_page_t *mres);
198 	int (*cdev_pg_ctor)(void *handle, vm_ooffset_t size, vm_prot_t prot,
199 	    vm_ooffset_t foff, struct ucred *cred, u_short *color);
200 	void (*cdev_pg_dtor)(void *handle);
201 };
202 
203 vm_object_t cdev_pager_allocate(void *handle, enum obj_type tp,
204     struct cdev_pager_ops *ops, vm_ooffset_t size, vm_prot_t prot,
205     vm_ooffset_t foff, struct ucred *cred);
206 vm_object_t cdev_pager_lookup(void *handle);
207 void cdev_pager_free_page(vm_object_t object, vm_page_t m);
208 
209 #endif				/* _KERNEL */
210 #endif				/* _VM_PAGER_ */
211