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[209.85.221.175]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-8920dd0c67csm928473241.10.2025.08.21.13.24.45 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Aug 2025 13:24:45 -0700 (PDT) Received: by mail-vk1-f175.google.com with SMTP id 71dfb90a1353d-53b17534eeeso554913e0c.3 for ; Thu, 21 Aug 2025 13:24:45 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCW5DCCQIh/txLvYQwGPP6q3Va7JnZvXSNYhZP7CQOhgKZk7FSeEAY8Tj9DLhLrsn9QU3cjSHy0u0w==@kvack.org X-Received: by 2002:a05:6122:1ad2:b0:53c:896e:2870 with SMTP id 71dfb90a1353d-53c8a40b923mr212315e0c.12.1755807884664; Thu, 21 Aug 2025 13:24:44 -0700 (PDT) MIME-Version: 1.0 References: <20250821200701.1329277-1-david@redhat.com> <20250821200701.1329277-32-david@redhat.com> In-Reply-To: <20250821200701.1329277-32-david@redhat.com> From: Linus Torvalds Date: Thu, 21 Aug 2025 16:24:23 -0400 X-Gmail-Original-Message-ID: X-Gm-Features: Ac12FXxaZhwn04a0gbwY6rjh9UGLxnRlGOG0Jy0WjRbVAG0UxLDqNy0Wydj0GQk Message-ID: Subject: Re: [PATCH RFC 31/35] crypto: remove nth_page() usage within SG entry To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, Herbert Xu , "David S. Miller" , Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, "Liam R. Howlett" , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Lorenzo Stoakes , Marco Elver , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4B9F61A0008 X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: p3y7dmbfn7pe79pecy74cze4f3659pni X-HE-Tag: 1755807886-324225 X-HE-Meta: U2FsdGVkX183OE4CXFtkNlFgp26wKW5BUJDg9gRmpOofgkOvUu09Hg78Nu04M0xo0OL6nEEvjArP6YHffDlclJDi+iPJGammbdg6bs4Jz8eWa2rE2qBWzOT+tldjd8YMPAxoKV78UgaktG9AbWgncgVLkc+btOThoBM5Co7yiJZBf1Xz0zbi4KDPNEBoV32hmGVXHHKz+2FbjyY2QZUshvtFEokPs1PpvDbnLnXUAFF9QKDgSPERW2ACQ0AjuCxmpduhk+1lHu4wf1Fd3Jm+4uMIop+JXbtHrLknH9wHZ8TcYhkKFtFpYfKzFe1xrXRU9IHgIqx2PiRDgFnWRlo2wPyKrY5HuxxuNI/Q3kE5b9vu4zupqnEa0dMmZ7Fj8daYx0Nlqfou+JrkcweS2DXmTsXZuQ7lGzGn0qJXTkWQfQ7IJHOOvPsrpCog1JcJHYOtOGAr0qZFXGzXh2iJ1ijcQnmIC8Q/7EoSQWhZh/paXR+Uegv5BX/vUu2Ld0kvrnjlkJV4Q8lxwfVJAGr4/q73gvipLd/jHplQxuI0mH+fPUrFxxoqYM4tTZrilSIHVduWnOnGlq6a1YMipudbCwU/hDrFwpj1V6CpF23KXXnIzZ2D2MT10vyBXbJmP7FQDjd+h+bblGywGWj8r8hRCZjpJ/ybssyMu2IOPrEx5QdLDoylJZi6OojB4oailBrG7bO/hik4lFsosBXD4bLg/UPyE+7C8kygY1qSjSlP2ONBdCJa/R+MaOhHPGulDwxfELG+lkZFOq/uUKXn5CpUv8BB1a1HJXCXNucz9jjNZvN+fuBu4QeF5PK8X582vc12D6ZrtCyg3rygOVWyx4cetXg3+Dj09BPuelfC3jN4Z8ZaH4P3VyFlcfgsqxoJymASCi4RgsjPh5JFpsy4nH/O+W4DPtm68B8IyqQkWmQUwmjJW00ZGGVd1C5OgV175yh6hFLvLD9T7DtaWI5qkQWM9gd 9UmHU4bK 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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 Thu, 21 Aug 2025 at 16:08, David Hildenbrand wrote: > > - page = nth_page(page, offset >> PAGE_SHIFT); > + page += offset / PAGE_SIZE; Please keep the " >> PAGE_SHIFT" form. Is "offset" unsigned? Yes it is, But I had to look at the source code to make sure, because it wasn't locally obvious from the patch. And I'd rather we keep a pattern that is "safe", in that it doesn't generate strange code if the value might be a 's64' (eg loff_t) on 32-bit architectures. Because doing a 64-bit shift on x86-32 is like three cycles. Doing a 64-bit signed division by a simple constant is something like ten strange instructions even if the end result is only 32-bit. And again - not the case *here*, but just a general "let's keep to one pattern", and the shift pattern is simply the better choice. Linus