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Date: Mon, 1 Jul 2024 23:52:10 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Barry Song <21cnbao@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Barry Song
 <v-songbaohua@oppo.com>, Yosry Ahmed <yosryahmed@google.com>, Nhat Pham
 <nphamcs@gmail.com>, Chengming Zhou <chengming.zhou@linux.dev>, Chris Li
 <chrisl@kernel.org>, David Hildenbrand <david@redhat.com>, Johannes Weiner
 <hannes@cmpxchg.org>, Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH] mm: zswap: fix zswap_never_enabled() for
 CONFIG_ZSWAP==N
Message-Id: <20240701235210.5c187c85aa225292d034cafc@linux-foundation.org>
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On Sun, 30 Jun 2024 11:22:31 +1200 Barry Song <21cnbao@gmail.com> wrote:

> From: Barry Song <v-songbaohua@oppo.com>
> 
> If CONFIG_ZSWAP is set to N, it means zswap cannot be enabled.
> zswap_never_enabled() should return true.
> 
> ...
>
> --- a/include/linux/zswap.h
> +++ b/include/linux/zswap.h
> @@ -68,7 +68,7 @@ static inline bool zswap_is_enabled(void)
>  
>  static inline bool zswap_never_enabled(void)
>  {
> -	return false;
> +	return true;
>  }

Well, that code was as wrong as it's possible to get.

But what effect does this have?  Seems "not much"?  Perhaps we'll
attempt a zswap_load() which later fails for other reasons?