xref: /linux/fs/debugfs/internal.h (revision c4101e55974cc7d835fbd2d8e01553a3f61e9e75)
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/list.h>
11 
12 struct file_operations;
13 
14 /* declared over in file.c */
15 extern const struct file_operations debugfs_noop_file_operations;
16 extern const struct file_operations debugfs_open_proxy_file_operations;
17 extern const struct file_operations debugfs_full_proxy_file_operations;
18 
19 struct debugfs_fsdata {
20 	const struct file_operations *real_fops;
21 	union {
22 		/* automount_fn is used when real_fops is NULL */
23 		debugfs_automount_t automount;
24 		struct {
25 			refcount_t active_users;
26 			struct completion active_users_drained;
27 
28 			/* protect cancellations */
29 			struct mutex cancellations_mtx;
30 			struct list_head cancellations;
31 		};
32 	};
33 };
34 
35 /*
36  * A dentry's ->d_fsdata either points to the real fops or to a
37  * dynamically allocated debugfs_fsdata instance.
38  * In order to distinguish between these two cases, a real fops
39  * pointer gets its lowest bit set.
40  */
41 #define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0)
42 
43 /* Access BITS */
44 #define DEBUGFS_ALLOW_API	BIT(0)
45 #define DEBUGFS_ALLOW_MOUNT	BIT(1)
46 
47 #ifdef CONFIG_DEBUG_FS_ALLOW_ALL
48 #define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_MOUNT | DEBUGFS_ALLOW_API)
49 #endif
50 #ifdef CONFIG_DEBUG_FS_DISALLOW_MOUNT
51 #define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_API)
52 #endif
53 #ifdef CONFIG_DEBUG_FS_ALLOW_NONE
54 #define DEFAULT_DEBUGFS_ALLOW_BITS (0)
55 #endif
56 
57 #endif /* _DEBUGFS_INTERNAL_H_ */
58