xref: /linux/fs/debugfs/internal.h (revision a634dda26186cf9a51567020fcce52bcba5e1e59)
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 extern const struct file_operations debugfs_full_short_proxy_file_operations;
19 
20 struct debugfs_fsdata {
21 	const struct file_operations *real_fops;
22 	const struct debugfs_short_fops *short_fops;
23 	union {
24 		/* automount_fn is used when real_fops is NULL */
25 		debugfs_automount_t automount;
26 		struct {
27 			refcount_t active_users;
28 			struct completion active_users_drained;
29 
30 			/* protect cancellations */
31 			struct mutex cancellations_mtx;
32 			struct list_head cancellations;
33 		};
34 	};
35 };
36 
37 /*
38  * A dentry's ->d_fsdata either points to the real fops or to a
39  * dynamically allocated debugfs_fsdata instance.
40  * In order to distinguish between these two cases, a real fops
41  * pointer gets its lowest bit set.
42  */
43 #define DEBUGFS_FSDATA_IS_REAL_FOPS_BIT BIT(0)
44 
45 /* Access BITS */
46 #define DEBUGFS_ALLOW_API	BIT(0)
47 #define DEBUGFS_ALLOW_MOUNT	BIT(1)
48 
49 #ifdef CONFIG_DEBUG_FS_ALLOW_ALL
50 #define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_MOUNT | DEBUGFS_ALLOW_API)
51 #endif
52 #ifdef CONFIG_DEBUG_FS_DISALLOW_MOUNT
53 #define DEFAULT_DEBUGFS_ALLOW_BITS (DEBUGFS_ALLOW_API)
54 #endif
55 #ifdef CONFIG_DEBUG_FS_ALLOW_NONE
56 #define DEFAULT_DEBUGFS_ALLOW_BITS (0)
57 #endif
58 
59 #endif /* _DEBUGFS_INTERNAL_H_ */
60