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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 1 Apr 2022 09:31:59 -0700
Message-ID: <CAHk-=wjToETfvzxkz_Y=QPt0JQRHF3VZ51xjhbPNAneHFvZofw@mail.gmail.com>
Subject: Re: [PATCH 2/2] mm: wrap __find_buddy_pfn() with a necessary buddy
 page validation.
To:     Zi Yan <ziy@nvidia.com>
Cc:     Linux-MM <linux-mm@kvack.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        David Hildenbrand <david@redhat.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>,
        Mike Rapoport <rppt@kernel.org>,
        Oscar Salvador <osalvador@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, Apr 1, 2022 at 6:58 AM Zi Yan <zi.yan@sent.com> wrote:
>
> +extern bool find_buddy_page_pfn(struct page *page, unsigned int order,
> +                               struct page **buddy, unsigned long *buddy_pfn);

Wouldn't it make more sense to just return the 'struct page *buddy'
here, instead of the 'bool'?

So a NULL buddy means the obvious "no buddy found".

I dislike those "pass return value by reference" in general, and the
above has _two_ of them.

We can get rid of at least one very obviously.

           Linus