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-rw-r--r--fs/debugfs/inode.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 1e30f74a9527..7fd4ec4bb214 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -248,6 +248,42 @@ static struct file_system_type debug_fs_type = {
};
MODULE_ALIAS_FS("debugfs");
+/**
+ * debugfs_lookup() - look up an existing debugfs file
+ * @name: a pointer to a string containing the name of the file to look up.
+ * @parent: a pointer to the parent dentry of the file.
+ *
+ * This function will return a pointer to a dentry if it succeeds. If the file
+ * doesn't exist or an error occurs, %NULL will be returned. The returned
+ * dentry must be passed to dput() when it is no longer needed.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.
+ */
+struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
+{
+ struct dentry *dentry;
+
+ if (IS_ERR(parent))
+ return NULL;
+
+ if (!parent)
+ parent = debugfs_mount->mnt_root;
+
+ inode_lock(d_inode(parent));
+ dentry = lookup_one_len(name, parent, strlen(name));
+ inode_unlock(d_inode(parent));
+
+ if (IS_ERR(dentry))
+ return NULL;
+ if (!d_really_is_positive(dentry)) {
+ dput(dentry);
+ return NULL;
+ }
+ return dentry;
+}
+EXPORT_SYMBOL_GPL(debugfs_lookup);
+
static struct dentry *start_creating(const char *name, struct dentry *parent)
{
struct dentry *dentry;