xref: /freebsd/sys/compat/linuxkpi/common/src/linux_shmemfs.c (revision b1bebaaba9b9c0ddfe503c43ca8e9e3917ee2c57)
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/param.h>
30 #include <sys/systm.h>
31 #include <sys/rwlock.h>
32 
33 #include <vm/vm.h>
34 #include <vm/pmap.h>
35 #include <vm/vm_object.h>
36 #include <vm/vm_map.h>
37 #include <vm/vm_page.h>
38 #include <vm/vm_pager.h>
39 
40 #include <linux/fs.h>
41 #include <linux/mm.h>
42 #include <linux/shmem_fs.h>
43 
44 struct page *
45 linux_shmem_read_mapping_page_gfp(vm_object_t obj, int pindex, gfp_t gfp)
46 {
47 	struct page *page;
48 	int rv;
49 
50 	if ((gfp & GFP_NOWAIT) != 0)
51 		panic("GFP_NOWAIT is unimplemented");
52 
53 	VM_OBJECT_WLOCK(obj);
54 	rv = vm_page_grab_valid(&page, obj, pindex, VM_ALLOC_NORMAL |
55 	    VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
56 	VM_OBJECT_WUNLOCK(obj);
57 	if (rv != VM_PAGER_OK)
58 		return (ERR_PTR(-EINVAL));
59 	return (page);
60 }
61 
62 struct linux_file *
63 linux_shmem_file_setup(const char *name, loff_t size, unsigned long flags)
64 {
65 	struct {
66 		struct linux_file file __aligned(sizeof(void *));
67 		struct vnode vnode __aligned(sizeof(void *));
68 	} *fileobj;
69 	struct linux_file *filp;
70 	struct vnode *vp;
71 	int error;
72 
73 	fileobj = kzalloc(sizeof(*fileobj), GFP_KERNEL);
74 	if (fileobj == NULL) {
75 		error = -ENOMEM;
76 		goto err_0;
77 	}
78 	filp = &fileobj->file;
79 	vp = &fileobj->vnode;
80 
81 	filp->f_count = 1;
82 	filp->f_vnode = vp;
83 	filp->f_shmem = vm_pager_allocate(OBJT_SWAP, NULL, size,
84 	    VM_PROT_READ | VM_PROT_WRITE, 0, curthread->td_ucred);
85 	if (filp->f_shmem == NULL) {
86 		error = -ENOMEM;
87 		goto err_1;
88 	}
89 	return (filp);
90 err_1:
91 	kfree(fileobj);
92 err_0:
93 	return (ERR_PTR(error));
94 }
95 
96 static vm_ooffset_t
97 linux_invalidate_mapping_pages_sub(vm_object_t obj, vm_pindex_t start,
98     vm_pindex_t end, int flags)
99 {
100 	int start_count, end_count;
101 
102 	VM_OBJECT_WLOCK(obj);
103 	start_count = obj->resident_page_count;
104 	vm_object_page_remove(obj, start, end, flags);
105 	end_count = obj->resident_page_count;
106 	VM_OBJECT_WUNLOCK(obj);
107 	return (start_count - end_count);
108 }
109 
110 unsigned long
111 linux_invalidate_mapping_pages(vm_object_t obj, pgoff_t start, pgoff_t end)
112 {
113 
114 	return (linux_invalidate_mapping_pages_sub(obj, start, end, OBJPR_CLEANONLY));
115 }
116 
117 void
118 linux_shmem_truncate_range(vm_object_t obj, loff_t lstart, loff_t lend)
119 {
120 	vm_pindex_t start = OFF_TO_IDX(lstart + PAGE_SIZE - 1);
121 	vm_pindex_t end = OFF_TO_IDX(lend + 1);
122 
123 	(void) linux_invalidate_mapping_pages_sub(obj, start, end, 0);
124 }
125