From: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
The debugfs function is used to get expected dentry.
Signed-off-by: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
---
fs/debugfs/inode.c | 26 ++++++++++++++++++++++++++
include/linux/debugfs.h | 9 +++++++++
2 files changed, 35 insertions(+), 0 deletions(-)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index b607d92..c6291bc 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -354,6 +354,32 @@ exit:
return dentry;
}
+struct dentry *debugfs_get_dentry(const char *name,
+ struct dentry *parent, int len)
+{
+ struct dentry *dentry = NULL;
+ int error = 0;
+
+ error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
+ &debugfs_mount_count);
+ if (error)
+ return NULL;
+
+ if (!parent)
+ parent = debugfs_mount->mnt_root;
+
+ mutex_lock(&parent->d_inode->i_mutex);
+ dentry = lookup_one_len(name, parent, strlen(name));
+ if (!IS_ERR(dentry)) {
+ mutex_unlock(&parent->d_inode->i_mutex);
+ return dentry;
+ }
+ mutex_unlock(&parent->d_inode->i_mutex);
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(debugfs_get_dentry);
+
/**
* debugfs_create_file - create a file in the debugfs filesystem
* @name: a pointer to a string containing the name of the file to create.
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 66c434f..8913a4d 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -46,6 +46,9 @@ extern struct dentry *arch_debugfs_dir;
extern const struct file_operations debugfs_file_operations;
extern const struct inode_operations debugfs_link_operations;
+struct dentry *debugfs_get_dentry(const char *name,
+ struct dentry *parent, int len);
+
struct dentry *debugfs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);
@@ -103,6 +106,12 @@ bool debugfs_initialized(void);
#include <linux/err.h>
+static inline struct dentry *debugfs_get_dentry(const char *name,
+ struct dentry *parent, int len)
+{
+ return ERR_PTR(-ENODEV);
+}
+
/*
* We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
* so users have a chance to detect if there was a real error or not. We don't
--
1.7.6.5
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