1 /* $NetBSD: shmem_fs.h,v 1.5 2022/08/20 23:49:31 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #ifndef _LINUX_SHMEM_FS_H_
33 #define _LINUX_SHMEM_FS_H_
34
35 #include <sys/types.h>
36 #include <sys/param.h>
37
38 #include <sys/rwlock.h>
39
40 #include <lib/libkern/libkern.h>
41
42 #include <uvm/uvm_extern.h>
43 #include <uvm/uvm_object.h>
44
45 #include <linux/err.h>
46 #include <linux/gfp.h>
47 #include <linux/mm_types.h>
48
49 static inline struct page *
shmem_read_mapping_page_gfp(struct uvm_object * uobj,voff_t i,gfp_t gfp)50 shmem_read_mapping_page_gfp(struct uvm_object *uobj, voff_t i, gfp_t gfp)
51 {
52 struct vm_page *vm_page;
53 int error;
54
55 error = uvm_obj_wirepages(uobj, i*PAGE_SIZE, (i + 1)*PAGE_SIZE, NULL);
56 if (error)
57 return ERR_PTR(-error); /* XXX errno NetBSD->Linux */
58
59 rw_enter(uobj->vmobjlock, RW_READER);
60 vm_page = uvm_pagelookup(uobj, i*PAGE_SIZE);
61 rw_exit(uobj->vmobjlock);
62
63 KASSERT(vm_page);
64 return container_of(vm_page, struct page, p_vmp);
65 }
66
67 static inline struct page *
shmem_read_mapping_page(struct uvm_object * uobj,voff_t i)68 shmem_read_mapping_page(struct uvm_object *uobj, voff_t i)
69 {
70 return shmem_read_mapping_page_gfp(uobj, i, GFP_KERNEL);
71 }
72
73 static inline void
shmem_truncate_range(struct uvm_object * uobj,voff_t start,voff_t end)74 shmem_truncate_range(struct uvm_object *uobj, voff_t start, voff_t end)
75 {
76 int flags = PGO_FREE;
77
78 if (start == 0 && end == -1) {
79 flags |= PGO_ALLPAGES;
80 } else {
81 KASSERT(0 <= start);
82 KASSERT(start <= end);
83 }
84
85 rw_enter(uobj->vmobjlock, RW_WRITER);
86 (*uobj->pgops->pgo_put)(uobj, start, end, flags);
87 }
88
89 #endif /* _LINUX_SHMEM_FS_H_ */
90