linux-kernel - md: dead code in md

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Message-ID: <3003e71d-ede0-0d55-973d-47c1c06e05ba@virtuozzo.com>
Date:   Thu, 20 Sep 2018 19:03:57 +0300
From:   Andrey Ryabinin <aryabinin@...tuozzo.com>
To:     NeilBrown <neilb@...e.com>, Shaohua Li <shli@...com>
Cc:     Kirill Tkhai <ktkhai@...tuozzo.com>, linux-raid@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: md: dead code in md_alloc()

Hi,
Kirill noticed that the following piece of code from md_alloc(dev, name)
is dead:
	if (name && dev)
		/*
		 * Creating /dev/mdNNN via "newarray", so adjust hold_active.
		 */
		mddev->hold_active = UNTIL_STOP;

md_alloc() is always called with either dev == 0 or name == NULL.

Judging from the commit that added this code:

039b7225e6e98783a7a7e79c52b29c437f29967d
Author: NeilBrown <neilb@...e.com>
Date:   Wed Apr 12 16:26:13 2017 +1000

    md: allow creation of mdNNN arrays via md_mod/parameters/new_array

and from the comment, it seems should be "if (!name && dev)".
But that would also change ->hold_active for created-by-open md devices,
and I'm not sure whether that would be a desirable change or not.