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Mon, 08 Sep 2025 08:02:30 -0700 (PDT) MIME-Version: 1.0 References: <20250905191357.78298-1-ryncsn@gmail.com> <20250905191357.78298-8-ryncsn@gmail.com> <84d3ab47-a960-4709-b127-ffbb8d85ac23@redhat.com> In-Reply-To: <84d3ab47-a960-4709-b127-ffbb8d85ac23@redhat.com> From: Kairui Song Date: Mon, 8 Sep 2025 23:01:53 +0800 X-Gm-Features: AS18NWBLumplG5EeNn7dHFCF9A5JT6QjZ8t-wBwCRBv-0-uNMUOyEV26HlI_I5w Message-ID: Subject: Re: [PATCH v2 07/15] mm, swap: tidy up swap device and cluster info helpers To: David Hildenbrand Cc: linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Hugh Dickins , Chris Li , Barry Song , Baoquan He , Nhat Pham , Kemeng Shi , Baolin Wang , Ying Huang , Johannes Weiner , Yosry Ahmed , Lorenzo Stoakes , Zi Yan , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 791E280007 X-Stat-Signature: zj4mn8unaa7kqaynaqwu9werj5jcing6 X-HE-Tag: 1757343752-547594 X-HE-Meta: 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 IyvoXI/a bM8E5JHj2IKoCiVV6VJPoTtXV8RqMslOOLK3vMEGq2mvwwwSc1zdJlLKIYl8Tch59aj/dJiuXsdQiHpSV1J8xLl669TkTRozRgZuGoSI9Qb+d3sMlh6dTxqRH9ovtt4MJ66bqOAjveYJZI3nqb4f6+GoWYbZUigNDjBsUJk7mw/84fEyXZcJO0ZqVBbXmLrfcSb6Ta2lFh7P9zzx57BfaW2qpimMo+/isrvU8N/kiWE8mS18Ix+U1cN9/P+UZwbCfp/e8EpbkcZZeQFS2ftzl4I0PonfaVt7AgyiKnsTL9896y3y3yIeoQS6Oag+nDJDQZKj+spjOfQ70fXujmciUV2J2OBfgYKY6NYUlJTRCP77cFVw3LzpVBR4SlyR9PXsCOcijUm3hQrX9rakpwcWJU5w0BmSWLBxkY43d2e8Bsq5OWIM= 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 Mon, Sep 8, 2025 at 8:52=E2=80=AFPM David Hildenbrand = wrote: > > On 05.09.25 21:13, Kairui Song wrote: > > 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 > > "Tidy this up and improve the function names." ? Yeah you are right. Most names actually got longer :) > > > swap entry/type is valid and the device is pinned, use the new introduc= ed > > __swap_entry_to_info/__swap_type_to_info instead. They have more debug > > sanity checks and lower overhead as they are inlined. > > > > Callers that may expect a NULL value should use > > swap_entry_to_info/swap_type_to_info instead. > > > > No feature change. The rearranged codes should have had no effect, or > > they should have been hitting NULL de-ref bugs already. Only some new > > sanity checks are added so potential issues may show up in debug build. > > > > The new helpers will be frequently used with swap table later when work= ing > > with swap cache folios. A locked swap cache folio ensures the entries a= re > > valid and stable so these helpers are very helpful. > > > > Signed-off-by: Kairui Song > > Acked-by: Chris Li > > Reviewed-by: Barry Song > > --- > > Acked-by: David Hildenbrand Thanks! > > -- > Cheers > > David / dhildenb > >