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-rw-r--r--Documentation/filesystems/debugfs.txt50
1 files changed, 29 insertions, 21 deletions
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 9e27c843d00e..dc497b96fa4f 100644
--- a/Documentation/filesystems/debugfs.txt
+++ b/Documentation/filesystems/debugfs.txt
@@ -68,41 +68,49 @@ actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
created with any of:
- struct dentry *debugfs_create_u8(const char *name, umode_t mode,
- struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_u16(const char *name, umode_t mode,
- struct dentry *parent, u16 *value);
+ void debugfs_create_u8(const char *name, umode_t mode,
+ struct dentry *parent, u8 *value);
+ void debugfs_create_u16(const char *name, umode_t mode,
+ struct dentry *parent, u16 *value);
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_u64(const char *name, umode_t mode,
- struct dentry *parent, u64 *value);
+ void debugfs_create_u64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value);
These files support both reading and writing the given value; if a specific
file should not be written to, simply set the mode bits accordingly. The
values in these files are in decimal; if hexadecimal is more appropriate,
the following functions can be used instead:
- struct dentry *debugfs_create_x8(const char *name, umode_t mode,
- struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_x16(const char *name, umode_t mode,
- struct dentry *parent, u16 *value);
- struct dentry *debugfs_create_x32(const char *name, umode_t mode,
- struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_x64(const char *name, umode_t mode,
- struct dentry *parent, u64 *value);
+ void debugfs_create_x8(const char *name, umode_t mode,
+ struct dentry *parent, u8 *value);
+ void debugfs_create_x16(const char *name, umode_t mode,
+ struct dentry *parent, u16 *value);
+ void debugfs_create_x32(const char *name, umode_t mode,
+ struct dentry *parent, u32 *value);
+ void debugfs_create_x64(const char *name, umode_t mode,
+ struct dentry *parent, u64 *value);
These functions are useful as long as the developer knows the size of the
value to be exported. Some types can have different widths on different
-architectures, though, complicating the situation somewhat. There is a
-function meant to help out in one special case:
+architectures, though, complicating the situation somewhat. There are
+functions meant to help out in such special cases:
- struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
- struct dentry *parent,
- size_t *value);
+ void debugfs_create_size_t(const char *name, umode_t mode,
+ struct dentry *parent, size_t *value);
As might be expected, this function will create a debugfs file to represent
a variable of type size_t.
+Similarly, there are helpers for variables of type unsigned long, in decimal
+and hexadecimal:
+
+ struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
+ struct dentry *parent,
+ unsigned long *value);
+ void debugfs_create_xul(const char *name, umode_t mode,
+ struct dentry *parent, unsigned long *value);
+
Boolean values can be placed in debugfs with:
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
@@ -114,8 +122,8 @@ lower-case values, or 1 or 0. Any other input will be silently ignored.
Also, atomic_t values can be placed in debugfs with:
- struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
- struct dentry *parent, atomic_t *value)
+ void debugfs_create_atomic_t(const char *name, umode_t mode,
+ struct dentry *parent, atomic_t *value)
A read of this file will get atomic_t values, and a write of this file
will set atomic_t values.