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Mon, 01 Sep 2025 23:02:23 -0700 (PDT) MIME-Version: 1.0 References: <20250822192023.13477-1-ryncsn@gmail.com> <20250822192023.13477-5-ryncsn@gmail.com> In-Reply-To: <20250822192023.13477-5-ryncsn@gmail.com> From: Barry Song <21cnbao@gmail.com> Date: Tue, 2 Sep 2025 14:02:11 +0800 X-Gm-Features: Ac12FXy6wS36mbX9MClREZ2t1AIDNIXLnTjeeWyfWCfJkczN6t5IXfD0myHNP7s Message-ID: Subject: Re: [PATCH 4/9] mm, swap: tidy up swap device and cluster info helpers To: Kairui Song Cc: linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Hugh Dickins , Chris Li , Baoquan He , Nhat Pham , Kemeng Shi , Baolin Wang , Ying Huang , Johannes Weiner , David Hildenbrand , Yosry Ahmed , Lorenzo Stoakes , Zi Yan , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 026C3C0008 X-Stat-Signature: 7xa71sxur1qxjkemweauz4t5t8esxtpz X-Rspam-User: X-HE-Tag: 1756792943-917762 X-HE-Meta: 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 Iz8TYrrT bbrHi8kX0b5RbK6o= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Aug 23, 2025 at 3:21=E2=80=AFAM Kairui Song wrot= e: > > From: Kairui Song > > swp_swap_info is the most commonly used helper for retrieving swap info. > It has an internal check that may lead to a NULL return value, but > almost none of its caller checks the return value, making the internal > check pointless. In fact, most of these callers already ensured the > entry is valid and never expect a NULL value. > > Tidy this up and shorten the name. If the caller can make sure the > swap entry/type is valid and the device is pinned, use the new introduced > swp_info/swp_type_info instead. They have more debug sanity checks and > lower overhead as they are inlined. > > Callers that may expect a NULL value should use > swp_get_info/swp_type_get_info instead. > > No feature change. The rearranged codes should have had no effect, or > they should have been hitting NULL de-ref bugs already. Some new sanity > checks have been added to the debug build to catch potential misuse. > And the new helpers will be used by swap cache when working with locked > swap cache folios, as a locked swap cache ensures the entries are valid > and stable. > > Signed-off-by: Kairui Song Reviewed-by: Barry Song Thanks Barry