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1/*
2 * Minimal file system backend for holding eBPF maps and programs,
3 * used by bpf(2) object pinning.
4 *
5 * Authors:
6 *
7 * Daniel Borkmann <daniel@iogearbox.net>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * version 2 as published by the Free Software Foundation.
12 */
13
14#include <linux/module.h>
15#include <linux/magic.h>
16#include <linux/major.h>
17#include <linux/mount.h>
18#include <linux/namei.h>
19#include <linux/fs.h>
20#include <linux/kdev_t.h>
21#include <linux/filter.h>
22#include <linux/bpf.h>
23
24enum bpf_type {
25 BPF_TYPE_UNSPEC = 0,
26 BPF_TYPE_PROG,
27 BPF_TYPE_MAP,
28};
29
30static void *bpf_any_get(void *raw, enum bpf_type type)
31{
32 switch (type) {
33 case BPF_TYPE_PROG:
34 raw = bpf_prog_inc(raw);
35 break;
36 case BPF_TYPE_MAP:
37 raw = bpf_map_inc(raw, true);
38 break;
39 default:
40 WARN_ON_ONCE(1);
41 break;
42 }
43
44 return raw;
45}
46
47static void bpf_any_put(void *raw, enum bpf_type type)
48{
49 switch (type) {
50 case BPF_TYPE_PROG:
51 bpf_prog_put(raw);
52 break;
53 case BPF_TYPE_MAP:
54 bpf_map_put_with_uref(raw);
55 break;
56 default:
57 WARN_ON_ONCE(1);
58 break;
59 }
60}
61
62static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
63{
64 void *raw;
65
66 *type = BPF_TYPE_MAP;
67 raw = bpf_map_get_with_uref(ufd);
68 if (IS_ERR(raw)) {
69 *type = BPF_TYPE_PROG;
70 raw = bpf_prog_get(ufd);
71 }
72
73 return raw;
74}
75
76static const struct inode_operations bpf_dir_iops;
77
78static const struct inode_operations bpf_prog_iops = { };
79static const struct inode_operations bpf_map_iops = { };
80
81static struct inode *bpf_get_inode(struct super_block *sb,
82 const struct inode *dir,
83 umode_t mode)
84{
85 struct inode *inode;
86
87 switch (mode & S_IFMT) {
88 case S_IFDIR:
89 case S_IFREG:
90 break;
91 default:
92 return ERR_PTR(-EINVAL);
93 }
94
95 inode = new_inode(sb);
96 if (!inode)
97 return ERR_PTR(-ENOSPC);
98
99 inode->i_ino = get_next_ino();
100 inode->i_atime = CURRENT_TIME;
101 inode->i_mtime = inode->i_atime;
102 inode->i_ctime = inode->i_atime;
103
104 inode_init_owner(inode, dir, mode);
105
106 return inode;
107}
108
109static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
110{
111 *type = BPF_TYPE_UNSPEC;
112 if (inode->i_op == &bpf_prog_iops)
113 *type = BPF_TYPE_PROG;
114 else if (inode->i_op == &bpf_map_iops)
115 *type = BPF_TYPE_MAP;
116 else
117 return -EACCES;
118
119 return 0;
120}
121
122static bool bpf_dname_reserved(const struct dentry *dentry)
123{
124 return strchr(dentry->d_name.name, '.');
125}
126
127static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
128{
129 struct inode *inode;
130
131 if (bpf_dname_reserved(dentry))
132 return -EPERM;
133
134 inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR);
135 if (IS_ERR(inode))
136 return PTR_ERR(inode);
137
138 inode->i_op = &bpf_dir_iops;
139 inode->i_fop = &simple_dir_operations;
140
141 inc_nlink(inode);
142 inc_nlink(dir);
143
144 d_instantiate(dentry, inode);
145 dget(dentry);
146
147 return 0;
148}
149
150static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,
151 umode_t mode, const struct inode_operations *iops)
152{
153 struct inode *inode;
154
155 if (bpf_dname_reserved(dentry))
156 return -EPERM;
157
158 inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);
159 if (IS_ERR(inode))
160 return PTR_ERR(inode);
161
162 inode->i_op = iops;
163 inode->i_private = dentry->d_fsdata;
164
165 d_instantiate(dentry, inode);
166 dget(dentry);
167
168 return 0;
169}
170
171static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,
172 dev_t devt)
173{
174 enum bpf_type type = MINOR(devt);
175
176 if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) ||
177 dentry->d_fsdata == NULL)
178 return -EPERM;
179
180 switch (type) {
181 case BPF_TYPE_PROG:
182 return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);
183 case BPF_TYPE_MAP:
184 return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);
185 default:
186 return -EPERM;
187 }
188}
189
190static int bpf_link(struct dentry *old_dentry, struct inode *dir,
191 struct dentry *new_dentry)
192{
193 if (bpf_dname_reserved(new_dentry))
194 return -EPERM;
195
196 return simple_link(old_dentry, dir, new_dentry);
197}
198
199static int bpf_rename(struct inode *old_dir, struct dentry *old_dentry,
200 struct inode *new_dir, struct dentry *new_dentry)
201{
202 if (bpf_dname_reserved(new_dentry))
203 return -EPERM;
204
205 return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
206}
207
208static const struct inode_operations bpf_dir_iops = {
209 .lookup = simple_lookup,
210 .mknod = bpf_mkobj,
211 .mkdir = bpf_mkdir,
212 .rmdir = simple_rmdir,
213 .rename = bpf_rename,
214 .link = bpf_link,
215 .unlink = simple_unlink,
216};
217
218static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
219 enum bpf_type type)
220{
221 struct dentry *dentry;
222 struct inode *dir;
223 struct path path;
224 umode_t mode;
225 dev_t devt;
226 int ret;
227
228 dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
229 if (IS_ERR(dentry))
230 return PTR_ERR(dentry);
231
232 mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
233 devt = MKDEV(UNNAMED_MAJOR, type);
234
235 ret = security_path_mknod(&path, dentry, mode, devt);
236 if (ret)
237 goto out;
238
239 dir = d_inode(path.dentry);
240 if (dir->i_op != &bpf_dir_iops) {
241 ret = -EPERM;
242 goto out;
243 }
244
245 dentry->d_fsdata = raw;
246 ret = vfs_mknod(dir, dentry, mode, devt);
247 dentry->d_fsdata = NULL;
248out:
249 done_path_create(&path, dentry);
250 return ret;
251}
252
253int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
254{
255 struct filename *pname;
256 enum bpf_type type;
257 void *raw;
258 int ret;
259
260 pname = getname(pathname);
261 if (IS_ERR(pname))
262 return PTR_ERR(pname);
263
264 raw = bpf_fd_probe_obj(ufd, &type);
265 if (IS_ERR(raw)) {
266 ret = PTR_ERR(raw);
267 goto out;
268 }
269
270 ret = bpf_obj_do_pin(pname, raw, type);
271 if (ret != 0)
272 bpf_any_put(raw, type);
273out:
274 putname(pname);
275 return ret;
276}
277
278static void *bpf_obj_do_get(const struct filename *pathname,
279 enum bpf_type *type)
280{
281 struct inode *inode;
282 struct path path;
283 void *raw;
284 int ret;
285
286 ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path);
287 if (ret)
288 return ERR_PTR(ret);
289
290 inode = d_backing_inode(path.dentry);
291 ret = inode_permission(inode, MAY_WRITE);
292 if (ret)
293 goto out;
294
295 ret = bpf_inode_type(inode, type);
296 if (ret)
297 goto out;
298
299 raw = bpf_any_get(inode->i_private, *type);
300 if (!IS_ERR(raw))
301 touch_atime(&path);
302
303 path_put(&path);
304 return raw;
305out:
306 path_put(&path);
307 return ERR_PTR(ret);
308}
309
310int bpf_obj_get_user(const char __user *pathname)
311{
312 enum bpf_type type = BPF_TYPE_UNSPEC;
313 struct filename *pname;
314 int ret = -ENOENT;
315 void *raw;
316
317 pname = getname(pathname);
318 if (IS_ERR(pname))
319 return PTR_ERR(pname);
320
321 raw = bpf_obj_do_get(pname, &type);
322 if (IS_ERR(raw)) {
323 ret = PTR_ERR(raw);
324 goto out;
325 }
326
327 if (type == BPF_TYPE_PROG)
328 ret = bpf_prog_new_fd(raw);
329 else if (type == BPF_TYPE_MAP)
330 ret = bpf_map_new_fd(raw);
331 else
332 goto out;
333
334 if (ret < 0)
335 bpf_any_put(raw, type);
336out:
337 putname(pname);
338 return ret;
339}
340
341static void bpf_evict_inode(struct inode *inode)
342{
343 enum bpf_type type;
344
345 truncate_inode_pages_final(&inode->i_data);
346 clear_inode(inode);
347
348 if (!bpf_inode_type(inode, &type))
349 bpf_any_put(inode->i_private, type);
350}
351
352static const struct super_operations bpf_super_ops = {
353 .statfs = simple_statfs,
354 .drop_inode = generic_delete_inode,
355 .evict_inode = bpf_evict_inode,
356};
357
358static int bpf_fill_super(struct super_block *sb, void *data, int silent)
359{
360 static struct tree_descr bpf_rfiles[] = { { "" } };
361 struct inode *inode;
362 int ret;
363
364 ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
365 if (ret)
366 return ret;
367
368 sb->s_op = &bpf_super_ops;
369
370 inode = sb->s_root->d_inode;
371 inode->i_op = &bpf_dir_iops;
372 inode->i_mode &= ~S_IALLUGO;
373 inode->i_mode |= S_ISVTX | S_IRWXUGO;
374
375 return 0;
376}
377
378static struct dentry *bpf_mount(struct file_system_type *type, int flags,
379 const char *dev_name, void *data)
380{
381 return mount_ns(type, flags, current->nsproxy->mnt_ns, bpf_fill_super);
382}
383
384static struct file_system_type bpf_fs_type = {
385 .owner = THIS_MODULE,
386 .name = "bpf",
387 .mount = bpf_mount,
388 .kill_sb = kill_litter_super,
389 .fs_flags = FS_USERNS_MOUNT,
390};
391
392MODULE_ALIAS_FS("bpf");
393
394static int __init bpf_init(void)
395{
396 int ret;
397
398 ret = sysfs_create_mount_point(fs_kobj, "bpf");
399 if (ret)
400 return ret;
401
402 ret = register_filesystem(&bpf_fs_type);
403 if (ret)
404 sysfs_remove_mount_point(fs_kobj, "bpf");
405
406 return ret;
407}
408fs_initcall(bpf_init);
1/*
2 * Minimal file system backend for holding eBPF maps and programs,
3 * used by bpf(2) object pinning.
4 *
5 * Authors:
6 *
7 * Daniel Borkmann <daniel@iogearbox.net>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * version 2 as published by the Free Software Foundation.
12 */
13
14#include <linux/init.h>
15#include <linux/magic.h>
16#include <linux/major.h>
17#include <linux/mount.h>
18#include <linux/namei.h>
19#include <linux/fs.h>
20#include <linux/kdev_t.h>
21#include <linux/parser.h>
22#include <linux/filter.h>
23#include <linux/bpf.h>
24
25enum bpf_type {
26 BPF_TYPE_UNSPEC = 0,
27 BPF_TYPE_PROG,
28 BPF_TYPE_MAP,
29};
30
31static void *bpf_any_get(void *raw, enum bpf_type type)
32{
33 switch (type) {
34 case BPF_TYPE_PROG:
35 raw = bpf_prog_inc(raw);
36 break;
37 case BPF_TYPE_MAP:
38 raw = bpf_map_inc(raw, true);
39 break;
40 default:
41 WARN_ON_ONCE(1);
42 break;
43 }
44
45 return raw;
46}
47
48static void bpf_any_put(void *raw, enum bpf_type type)
49{
50 switch (type) {
51 case BPF_TYPE_PROG:
52 bpf_prog_put(raw);
53 break;
54 case BPF_TYPE_MAP:
55 bpf_map_put_with_uref(raw);
56 break;
57 default:
58 WARN_ON_ONCE(1);
59 break;
60 }
61}
62
63static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
64{
65 void *raw;
66
67 *type = BPF_TYPE_MAP;
68 raw = bpf_map_get_with_uref(ufd);
69 if (IS_ERR(raw)) {
70 *type = BPF_TYPE_PROG;
71 raw = bpf_prog_get(ufd);
72 }
73
74 return raw;
75}
76
77static const struct inode_operations bpf_dir_iops;
78
79static const struct inode_operations bpf_prog_iops = { };
80static const struct inode_operations bpf_map_iops = { };
81
82static struct inode *bpf_get_inode(struct super_block *sb,
83 const struct inode *dir,
84 umode_t mode)
85{
86 struct inode *inode;
87
88 switch (mode & S_IFMT) {
89 case S_IFDIR:
90 case S_IFREG:
91 case S_IFLNK:
92 break;
93 default:
94 return ERR_PTR(-EINVAL);
95 }
96
97 inode = new_inode(sb);
98 if (!inode)
99 return ERR_PTR(-ENOSPC);
100
101 inode->i_ino = get_next_ino();
102 inode->i_atime = current_time(inode);
103 inode->i_mtime = inode->i_atime;
104 inode->i_ctime = inode->i_atime;
105
106 inode_init_owner(inode, dir, mode);
107
108 return inode;
109}
110
111static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
112{
113 *type = BPF_TYPE_UNSPEC;
114 if (inode->i_op == &bpf_prog_iops)
115 *type = BPF_TYPE_PROG;
116 else if (inode->i_op == &bpf_map_iops)
117 *type = BPF_TYPE_MAP;
118 else
119 return -EACCES;
120
121 return 0;
122}
123
124static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode,
125 struct inode *dir)
126{
127 d_instantiate(dentry, inode);
128 dget(dentry);
129
130 dir->i_mtime = current_time(dir);
131 dir->i_ctime = dir->i_mtime;
132}
133
134static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
135{
136 struct inode *inode;
137
138 inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR);
139 if (IS_ERR(inode))
140 return PTR_ERR(inode);
141
142 inode->i_op = &bpf_dir_iops;
143 inode->i_fop = &simple_dir_operations;
144
145 inc_nlink(inode);
146 inc_nlink(dir);
147
148 bpf_dentry_finalize(dentry, inode, dir);
149 return 0;
150}
151
152static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,
153 umode_t mode, const struct inode_operations *iops)
154{
155 struct inode *inode;
156
157 inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);
158 if (IS_ERR(inode))
159 return PTR_ERR(inode);
160
161 inode->i_op = iops;
162 inode->i_private = dentry->d_fsdata;
163
164 bpf_dentry_finalize(dentry, inode, dir);
165 return 0;
166}
167
168static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,
169 dev_t devt)
170{
171 enum bpf_type type = MINOR(devt);
172
173 if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) ||
174 dentry->d_fsdata == NULL)
175 return -EPERM;
176
177 switch (type) {
178 case BPF_TYPE_PROG:
179 return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);
180 case BPF_TYPE_MAP:
181 return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);
182 default:
183 return -EPERM;
184 }
185}
186
187static struct dentry *
188bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
189{
190 if (strchr(dentry->d_name.name, '.'))
191 return ERR_PTR(-EPERM);
192
193 return simple_lookup(dir, dentry, flags);
194}
195
196static int bpf_symlink(struct inode *dir, struct dentry *dentry,
197 const char *target)
198{
199 char *link = kstrdup(target, GFP_USER | __GFP_NOWARN);
200 struct inode *inode;
201
202 if (!link)
203 return -ENOMEM;
204
205 inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO | S_IFLNK);
206 if (IS_ERR(inode)) {
207 kfree(link);
208 return PTR_ERR(inode);
209 }
210
211 inode->i_op = &simple_symlink_inode_operations;
212 inode->i_link = link;
213
214 bpf_dentry_finalize(dentry, inode, dir);
215 return 0;
216}
217
218static const struct inode_operations bpf_dir_iops = {
219 .lookup = bpf_lookup,
220 .mknod = bpf_mkobj,
221 .mkdir = bpf_mkdir,
222 .symlink = bpf_symlink,
223 .rmdir = simple_rmdir,
224 .rename = simple_rename,
225 .link = simple_link,
226 .unlink = simple_unlink,
227};
228
229static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
230 enum bpf_type type)
231{
232 struct dentry *dentry;
233 struct inode *dir;
234 struct path path;
235 umode_t mode;
236 dev_t devt;
237 int ret;
238
239 dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
240 if (IS_ERR(dentry))
241 return PTR_ERR(dentry);
242
243 mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
244 devt = MKDEV(UNNAMED_MAJOR, type);
245
246 ret = security_path_mknod(&path, dentry, mode, devt);
247 if (ret)
248 goto out;
249
250 dir = d_inode(path.dentry);
251 if (dir->i_op != &bpf_dir_iops) {
252 ret = -EPERM;
253 goto out;
254 }
255
256 dentry->d_fsdata = raw;
257 ret = vfs_mknod(dir, dentry, mode, devt);
258 dentry->d_fsdata = NULL;
259out:
260 done_path_create(&path, dentry);
261 return ret;
262}
263
264int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
265{
266 struct filename *pname;
267 enum bpf_type type;
268 void *raw;
269 int ret;
270
271 pname = getname(pathname);
272 if (IS_ERR(pname))
273 return PTR_ERR(pname);
274
275 raw = bpf_fd_probe_obj(ufd, &type);
276 if (IS_ERR(raw)) {
277 ret = PTR_ERR(raw);
278 goto out;
279 }
280
281 ret = bpf_obj_do_pin(pname, raw, type);
282 if (ret != 0)
283 bpf_any_put(raw, type);
284out:
285 putname(pname);
286 return ret;
287}
288
289static void *bpf_obj_do_get(const struct filename *pathname,
290 enum bpf_type *type)
291{
292 struct inode *inode;
293 struct path path;
294 void *raw;
295 int ret;
296
297 ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path);
298 if (ret)
299 return ERR_PTR(ret);
300
301 inode = d_backing_inode(path.dentry);
302 ret = inode_permission(inode, MAY_WRITE);
303 if (ret)
304 goto out;
305
306 ret = bpf_inode_type(inode, type);
307 if (ret)
308 goto out;
309
310 raw = bpf_any_get(inode->i_private, *type);
311 if (!IS_ERR(raw))
312 touch_atime(&path);
313
314 path_put(&path);
315 return raw;
316out:
317 path_put(&path);
318 return ERR_PTR(ret);
319}
320
321int bpf_obj_get_user(const char __user *pathname)
322{
323 enum bpf_type type = BPF_TYPE_UNSPEC;
324 struct filename *pname;
325 int ret = -ENOENT;
326 void *raw;
327
328 pname = getname(pathname);
329 if (IS_ERR(pname))
330 return PTR_ERR(pname);
331
332 raw = bpf_obj_do_get(pname, &type);
333 if (IS_ERR(raw)) {
334 ret = PTR_ERR(raw);
335 goto out;
336 }
337
338 if (type == BPF_TYPE_PROG)
339 ret = bpf_prog_new_fd(raw);
340 else if (type == BPF_TYPE_MAP)
341 ret = bpf_map_new_fd(raw);
342 else
343 goto out;
344
345 if (ret < 0)
346 bpf_any_put(raw, type);
347out:
348 putname(pname);
349 return ret;
350}
351
352static void bpf_evict_inode(struct inode *inode)
353{
354 enum bpf_type type;
355
356 truncate_inode_pages_final(&inode->i_data);
357 clear_inode(inode);
358
359 if (S_ISLNK(inode->i_mode))
360 kfree(inode->i_link);
361 if (!bpf_inode_type(inode, &type))
362 bpf_any_put(inode->i_private, type);
363}
364
365static const struct super_operations bpf_super_ops = {
366 .statfs = simple_statfs,
367 .drop_inode = generic_delete_inode,
368 .show_options = generic_show_options,
369 .evict_inode = bpf_evict_inode,
370};
371
372enum {
373 OPT_MODE,
374 OPT_ERR,
375};
376
377static const match_table_t bpf_mount_tokens = {
378 { OPT_MODE, "mode=%o" },
379 { OPT_ERR, NULL },
380};
381
382struct bpf_mount_opts {
383 umode_t mode;
384};
385
386static int bpf_parse_options(char *data, struct bpf_mount_opts *opts)
387{
388 substring_t args[MAX_OPT_ARGS];
389 int option, token;
390 char *ptr;
391
392 opts->mode = S_IRWXUGO;
393
394 while ((ptr = strsep(&data, ",")) != NULL) {
395 if (!*ptr)
396 continue;
397
398 token = match_token(ptr, bpf_mount_tokens, args);
399 switch (token) {
400 case OPT_MODE:
401 if (match_octal(&args[0], &option))
402 return -EINVAL;
403 opts->mode = option & S_IALLUGO;
404 break;
405 /* We might like to report bad mount options here, but
406 * traditionally we've ignored all mount options, so we'd
407 * better continue to ignore non-existing options for bpf.
408 */
409 }
410 }
411
412 return 0;
413}
414
415static int bpf_fill_super(struct super_block *sb, void *data, int silent)
416{
417 static struct tree_descr bpf_rfiles[] = { { "" } };
418 struct bpf_mount_opts opts;
419 struct inode *inode;
420 int ret;
421
422 save_mount_options(sb, data);
423
424 ret = bpf_parse_options(data, &opts);
425 if (ret)
426 return ret;
427
428 ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
429 if (ret)
430 return ret;
431
432 sb->s_op = &bpf_super_ops;
433
434 inode = sb->s_root->d_inode;
435 inode->i_op = &bpf_dir_iops;
436 inode->i_mode &= ~S_IALLUGO;
437 inode->i_mode |= S_ISVTX | opts.mode;
438
439 return 0;
440}
441
442static struct dentry *bpf_mount(struct file_system_type *type, int flags,
443 const char *dev_name, void *data)
444{
445 return mount_nodev(type, flags, data, bpf_fill_super);
446}
447
448static struct file_system_type bpf_fs_type = {
449 .owner = THIS_MODULE,
450 .name = "bpf",
451 .mount = bpf_mount,
452 .kill_sb = kill_litter_super,
453};
454
455static int __init bpf_init(void)
456{
457 int ret;
458
459 ret = sysfs_create_mount_point(fs_kobj, "bpf");
460 if (ret)
461 return ret;
462
463 ret = register_filesystem(&bpf_fs_type);
464 if (ret)
465 sysfs_remove_mount_point(fs_kobj, "bpf");
466
467 return ret;
468}
469fs_initcall(bpf_init);