xref: /freebsd/sys/compat/linuxkpi/common/src/linux_shmemfs.c (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
1 /*-
2  * Copyright (c) 2010 Isilon Systems, Inc.
3  * Copyright (c) 2016 Matthew Macy (mmacy@mattmacy.io)
4  * Copyright (c) 2017 Mellanox Technologies, Ltd.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/rwlock.h>
35 
36 #include <vm/vm.h>
37 #include <vm/pmap.h>
38 #include <vm/vm_object.h>
39 #include <vm/vm_map.h>
40 #include <vm/vm_page.h>
41 #include <vm/vm_pager.h>
42 
43 #include <linux/fs.h>
44 #include <linux/mm.h>
45 #include <linux/shmem_fs.h>
46 
47 struct page *
48 linux_shmem_read_mapping_page_gfp(vm_object_t obj, int pindex, gfp_t gfp)
49 {
50 	vm_page_t page;
51 	int rv;
52 
53 	if ((gfp & GFP_NOWAIT) != 0)
54 		panic("GFP_NOWAIT is unimplemented");
55 
56 	VM_OBJECT_WLOCK(obj);
57 	rv = vm_page_grab_valid(&page, obj, pindex, VM_ALLOC_NORMAL |
58 	    VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
59 	VM_OBJECT_WUNLOCK(obj);
60 	if (rv != VM_PAGER_OK)
61 		return (ERR_PTR(-EINVAL));
62 	return (page);
63 }
64 
65 struct linux_file *
66 linux_shmem_file_setup(const char *name, loff_t size, unsigned long flags)
67 {
68 	struct fileobj {
69 		struct linux_file file __aligned(sizeof(void *));
70 		struct vnode vnode __aligned(sizeof(void *));
71 	};
72 	struct fileobj *fileobj;
73 	struct linux_file *filp;
74 	struct vnode *vp;
75 	int error;
76 
77 	fileobj = kzalloc(sizeof(*fileobj), GFP_KERNEL);
78 	if (fileobj == NULL) {
79 		error = -ENOMEM;
80 		goto err_0;
81 	}
82 	filp = &fileobj->file;
83 	vp = &fileobj->vnode;
84 
85 	filp->f_count = 1;
86 	filp->f_vnode = vp;
87 	filp->f_shmem = vm_pager_allocate(OBJT_SWAP, NULL, size,
88 	    VM_PROT_READ | VM_PROT_WRITE, 0, curthread->td_ucred);
89 	if (filp->f_shmem == NULL) {
90 		error = -ENOMEM;
91 		goto err_1;
92 	}
93 	return (filp);
94 err_1:
95 	kfree(filp);
96 err_0:
97 	return (ERR_PTR(error));
98 }
99 
100 static vm_ooffset_t
101 linux_invalidate_mapping_pages_sub(vm_object_t obj, vm_pindex_t start,
102     vm_pindex_t end, int flags)
103 {
104 	int start_count, end_count;
105 
106 	VM_OBJECT_WLOCK(obj);
107 	start_count = obj->resident_page_count;
108 	vm_object_page_remove(obj, start, end, flags);
109 	end_count = obj->resident_page_count;
110 	VM_OBJECT_WUNLOCK(obj);
111 	return (start_count - end_count);
112 }
113 
114 unsigned long
115 linux_invalidate_mapping_pages(vm_object_t obj, pgoff_t start, pgoff_t end)
116 {
117 
118 	return (linux_invalidate_mapping_pages_sub(obj, start, end, OBJPR_CLEANONLY));
119 }
120 
121 void
122 linux_shmem_truncate_range(vm_object_t obj, loff_t lstart, loff_t lend)
123 {
124 	vm_pindex_t start = OFF_TO_IDX(lstart + PAGE_SIZE - 1);
125 	vm_pindex_t end = OFF_TO_IDX(lend + 1);
126 
127 	(void) linux_invalidate_mapping_pages_sub(obj, start, end, 0);
128 }
129