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charset="utf-8" X-RootMTR: 20230807152704eucas1p1bbe08af4559a7d2984198fe8ba487a2e X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20230807152704eucas1p1bbe08af4559a7d2984198fe8ba487a2e References: <20230807152657.1692414-1-m.szyprowski@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 07.08.2023 18:23, Matthew Wilcox wrote: > On Mon, Aug 07, 2023 at 05:26:57PM +0200, Marek Szyprowski wrote: >> It is possible that the folio_size() of the next folio returns zero, so > What? How can folio_size() return zero? > > return PAGE_SIZE << folio_order(folio); > > It is a minimum of PAGE_SIZE. Well, the folio_order() on that next folio returns 255, so folio_size() overflows to zero. However, the main source of this issue is relying on the properties of the folio beyond the requested sync region. > ... Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland