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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Ying Huang , Baolin Wang , Barry Song , Ryan Roberts , Chuanhua Han , Kiryl Shutsemau , Kyle Zeng , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm: fix address wraparound when scanning large folio PTEs Message-ID: References: <20261013-folio_pte_scan_range-v1-1-c50dc30bf6ad@kernel.org> <9add8400-66c1-47e9-b5af-7a4081ebf3c4@kernel.org> <06930044-4bcb-4478-8a6f-2dd3cf6d290e@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <06930044-4bcb-4478-8a6f-2dd3cf6d290e@kernel.org> X-Stat-Signature: 87xc6kc5ykjgney4367jiuowwmdfako4 X-Rspamd-Queue-Id: 148ED2000D X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1791989769-532089 X-HE-Meta: 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 prfnPi05 +4uZaS/MnoRa61xU/t9UZGsF1+/z+l5sKH5mT8HBHUxEiwmQB9ZDiAWlIdZa080711H4057DXtOEldMGsTHYzG2shzt4F1at0JnMdYj9Y8RRCSQC3z1q3hUyDdLWJLpfVSIF4L5MjmpleCzcuYzIPWXWzabzAF/EftJHvc1NI5fG/abLaYt/MCR/MR/L4/Jpzp1F1ihezUETFrO4kH/bmrPTGARYcBAoOF1WFqz6+wkPBdiDlciz/9GUwokGQPFdRXp4DonhrjEAVNirqau6aOZFVlZV+0Ya/5Z62T0aEvYRiKqQkxo29vFH1mZXbk1rjuoArAZQRodW+4azUZhLe7m58gbmhxfXPObIk Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Oct 14, 2026 at 03:45:41PM +0200, David Hildenbrand (Arm) wrote: > It's the following thing that adds confusion: > > include/asm-generic/pgtable-nopmd.h:#define pmd_addr_end(addr, end) > (end) Ah ugh :) of course. > What I am saying is that I don't agree with adding another two const variables > with names that are less intuitive than just saying the computation. Let me try > to improve the comment: > > /* Avoid address wraparounds by not adding/subtracting beyond limits. */ The variables are a (possibly) neat way of self-documenting that, but then possibly adds complexity by having yet another variable :) A comment works for me, though the confusing bit I guess is knowing which bit exactly might overflow. So maybe saying 'avoid wraparounds of ' and a brief bit about how would help? -- Cheers, Lorenzo