debugfs: warn if file creation failed due to uninitialized debugfs

Improve debugfs_start_creating() to warn if it was used before debugfs
initialization. It silently returned ERR_PTR(-ENOENT) before, but it is
hard to find the cause of failure especially if it was called by
debugfs_create_dir(), because the document of the function says:

> NOTE: it's expected that most callers should _ignore_ the errors returned
> by this function. Other debugfs functions handle the fact that the "dentry"
> passed to them could be an error and they don't crash in that case.
> Drivers should generally work fine even if debugfs fails to init anyway.

Signed-off-by: Yohei Kojima <yk@y-koj.net>
Link: https://patch.msgid.link/6d1dc775f7d5e754d734907514534054f682bac5.1781171918.git.yk@y-koj.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions