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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pAFxU-008Gel-II; Tue, 27 Dec 2022 19:49:56 +0000 Date: Tue, 27 Dec 2022 19:49:56 +0000 From: Matthew Wilcox To: SeongJae Park Cc: Kefeng Wang , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, vishal.moola@gmail.com, david@redhat.com Subject: Re: [PATCH -next v2 2/7] mm: damon: introduce damon_get_folio() Message-ID: References: <20221227122714.161224-3-wangkefeng.wang@huawei.com> <20221227194257.2744-1-sj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221227194257.2744-1-sj@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 78111180017 X-Stat-Signature: y8ja8ffy89jhe6csrubnnhxytbk1qjmi X-HE-Tag: 1672170602-470755 X-HE-Meta: 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 zQjuhBuA VLEr+ 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: On Tue, Dec 27, 2022 at 07:42:57PM +0000, SeongJae Park wrote: > > +static inline struct page *damon_get_page(unsigned long pfn) > > +{ > > + struct folio *folio = damon_get_folio(pfn); > > + > > + return &folio->page; > > I think we should check if folio is NULL before dereferencing it? &folio->page does not dereeference folio.