xref: /linux/fs/debugfs/internal.h (revision d8b45ee43a0562867d4fbe196e7747226c0a3d13)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  *  internal.h - declarations internal to debugfs
4  *
5  *  Copyright (C) 2016 Nicolai Stange <nicstange@gmail.com>
6  */
7 
8 #ifndef _DEBUGFS_INTERNAL_H_
9 #define _DEBUGFS_INTERNAL_H_
10 #include <linux/lockdep.h>
11 #include <linux/list.h>
12 
13 struct file_operations;
14 
15 /* declared over in file.c */
16 extern const struct file_operations debugfs_noop_file_operations;
17 extern const struct file_operations debugfs_open_proxy_file_operations;
18 extern const struct file_operations debugfs_full_proxy_file_operations;
19 
20 struct debugfs_fsdata {
21 	const struct file_operations *real_fops;
22 	union {
23 		/* automount_fn is used when real_fops is NULL */
24 		debugfs_automount_t automount;
25 		struct {
26 			refcount_t active_users;
27 			struct completion active_users_drained;
28 #ifdef CONFIG_LOCKDEP
29 			struct lockdep_map lockdep_map;
30 			struct lock_class_key key;
31 			char *lock_name;
32 #endif
33 
34 			/* protect cancellations */
35 			struct mutex cancellations_mtx;
36 			struct list_head cancellations;
37 		};
38 	};
39 };
40 
41 /*
42  * A dentry's ->d_fsdata either points to the real fops or to a
43  * dynamically allocated debugfs_fsdata instance.
44  * In order to distinguish between these two cases, a real fops
45  * pointer gets its lowest bit set.
46  */
47 #define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0)
48 
49 /* Access BITS */
50 #define DEBUGFS_ALLOW_API	BIT(0)
51 #define DEBUGFS_ALLOW_MOUNT	BIT(1)
52 
53 #ifdef CONFIG_DEBUG_FS_ALLOW_ALL
54 #define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_MOUNT | DEBUGFS_ALLOW_API)
55 #endif
56 #ifdef CONFIG_DEBUG_FS_DISALLOW_MOUNT
57 #define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_API)
58 #endif
59 #ifdef CONFIG_DEBUG_FS_ALLOW_NONE
60 #define DEFAULT_DEBUGFS_ALLOW_BITS (0)
61 #endif
62 
63 #endif /* _DEBUGFS_INTERNAL_H_ */
64