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Subject: Re: [PATCH] net: mac80211: use IS_ERR to check return value
From:   Johannes Berg <johannes@sipsolutions.net>
To:     yingsha xu <ysxu@hust.edu.cn>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Jiri Benc <jbenc@suse.cz>,
        "John W. Linville" <linville@tuxdriver.com>
Cc:     hust-os-kernel-patches@googlegroups.com,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Tue, 18 Apr 2023 10:36:14 +0200
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On Sun, 2023-04-16 at 16:30 +0800, yingsha xu wrote:
> According to the annotation of function debugfs_create_fs, if
> an error occurs, ERR_PTR(-ERROR) will be returned instead of
> a null pointer or zero value.
>=20
> Fix it by using IS_ERR().

I don't this this is right, or fixed anything ...

If debugfs indeed returned an ERR_PTR() value, then the later debugfs
adds will do nothing.

Since it doesn't look like debugfs_create_dir() can actually return NULL
these days (not sure it ever could), I guess we can even remove the
check.

But you could've just read the comment there too, to know what the NULL
check was about ...

johannes