linux-kernel - Re: [PATCH v2 2/3] mm/memory_hotplug: Drop mem_blk check from unregister_mem_sect_under

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Message-ID: <20180814093652.GA6878@techadventures.net>
Date:   Tue, 14 Aug 2018 11:36:52 +0200
From:   Oscar Salvador <osalvador@...hadventures.net>
To:     David Hildenbrand <david@...hat.com>
Cc:     akpm@...ux-foundation.org, mhocko@...e.com,
        dan.j.williams@...el.com, jglisse@...hat.com, rafael@...nel.org,
        yasu.isimatu@...il.com, logang@...tatee.com, dave.jiang@...el.com,
        Jonathan.Cameron@...wei.com, vbabka@...e.cz, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Oscar Salvador <osalvador@...e.de>
Subject: Re: [PATCH v2 2/3] mm/memory_hotplug: Drop mem_blk check from
 unregister_mem_sect_under_nodes

On Tue, Aug 14, 2018 at 11:30:51AM +0200, David Hildenbrand wrote:

> 
> While it is correct in current code, I wonder if this sanity check
> should stay. I would completely agree if it would be a static function.

Hi David,

Well, unregister_mem_sect_under_nodes() __only__ gets called from remove_memory_section().
But remove_memory_section() only calls unregister_mem_sect_under_nodes() IFF mem_blk
is not NULL:

static int remove_memory_section
{
	...
	mem = find_memory_block(section);
	if (!mem)
		goto out_unlock;

	unregister_mem_sect_under_nodes(mem, __section_nr(section));
	...
}

So, to me keeping the check is redundant, as we already check for it before calling in.

Thanks
-- 
Oscar Salvador
SUSE L3