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Wed, 16 Jul 2025 10:59:44 -0700 (PDT) Date: Wed, 16 Jul 2025 20:59:42 +0300 From: Dan Carpenter To: Zi Yan Cc: David Hildenbrand , Lorenzo Stoakes , Antonio Quartulli , linux-mm@kvack.org, Andrew Morton , Hugh Dickins , Kirill Shutemov , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/huge_memory: refactor after-split (page) cache code. Message-ID: <38ef66fa-f10d-43ac-a650-233d53cfe65b@suswa.mountain> References: <20250716171112.3666150-1-ziy@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250716171112.3666150-1-ziy@nvidia.com> X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 1DC7910000E X-Stat-Signature: 5n1ahq13nu7y4s1jdihg5kka396ebzru X-HE-Tag: 1752688785-22174 X-HE-Meta: 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 bpTcnYDR 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 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 Wed, Jul 16, 2025 at 01:11:12PM -0400, Zi Yan wrote: > Smatch/coverity checkers report NULL mapping referencing issues[1][2][3] > every time the code is modified, because they do not understand that > mapping cannot be NULL when a folio is in page cache in the code. > Refactor the code to make it explicit. > > No functional change is intended. > > [1]https://lore.kernel.org/linux-mm/2afe3d59-aca5-40f7-82a3-a6d976fb0f4f@stanley.mountain/ > [2]https://lore.kernel.org/oe-kbuild/64b54034-f311-4e7d-b935-c16775dbb642@suswa.mountain/ > [3]https://lore.kernel.org/linux-mm/20250716145804.4836-1-antonio@mandelbit.com/ > > Suggested-by: David Hildenbrand > Signed-off-by: Zi Yan > --- This silences the Smatch warning. :) regards, dan carpenter