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(unknown [IPv6:2a01:e0a:5e3:6100:826d:bc07:e98c:84a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: loicmolinari) by bali.collaboradmins.com (Postfix) with ESMTPSA id 15C9017E1155; Fri, 5 Dec 2025 19:22:35 +0100 (CET) From: =?UTF-8?q?Lo=C3=AFc=20Molinari?= To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , Boris Brezillon , Rob Herring , Steven Price , Liviu Dudau , Melissa Wen , =?UTF-8?q?Ma=C3=ADra=20Canal?= , Hugh Dickins , Baolin Wang , Andrew Morton , =?UTF-8?q?Lo=C3=AFc=20Molinari?= , Al Viro , =?UTF-8?q?Miko=C5=82aj=20Wasiak?= , Christian Brauner , Nitin Gote , Andi Shyti , Jonathan Corbet , Christopher Healy , Matthew Wilcox , Bagas Sanjaya Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, kernel@collabora.com Subject: [PATCH v13 01/10] drm/shmem-helper: Simplify page offset calculation in fault handler Date: Fri, 5 Dec 2025 19:22:22 +0100 Message-ID: <20251205182231.194072-2-loic.molinari@collabora.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251205182231.194072-1-loic.molinari@collabora.com> References: <20251205182231.194072-1-loic.molinari@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 5FF0C10000D X-Stat-Signature: e7ghmjppa5gomqd9zzkcxfo3h4f5wbg7 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1764958958-318018 X-HE-Meta: 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 exXh+OK6 UPNOVLjMIkWxUwElGXZlfRH06CUFGrL6jMFrte63EbfAtx2qH/7J7fSzjdhqpVFdVv8xjlhX6yajMJMe+E8hezzjC5vYVz7FsoacyNbmSzY6u60vw8ZNWEi0w99kQIalxXgzxWdxM4WJE1rP8klZwxdZ+NOTGoAp6W6aoni/dDjH1kWYPRw0kyBQfdkEBF9FcncFSmsVmxpq4ksBDEPBe/7IaYFqCQNf2TUesVbvXUn984ROGbaj0aVyMPNnHJIeZwJdQKzkTo4y095K2Z5TbCfGiuO/SFhXKTNc7zbnGrGl3BxBSOQKHI4DK5lW3/FTfijg0e0kktpBy2M8K0wfmHCG6yQ1r8MPb8jdPtBO6jM6gnmS8jEIRHF0S9d/FX8zGaP0W 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: For a fault at address addr, the page offset is page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT = ((addr & PAGE_MASK) - vma->vm_start) >> PAGE_SHIFT = (addr - vma->vm_start) >> PAGE_SHIFT Since the faulty logical page offset based on VMA is vmf->pgoff = vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) We can slightly simplify the calculation using page_offset = vmf->pgoff - vma->vm_pgoff v11: - remove misleading comment - add Boris R-b Signed-off-by: Loïc Molinari Reviewed-by: Boris Brezillon --- drivers/gpu/drm/drm_gem_shmem_helper.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index dc94a27710e5..e47ab3ebb5c2 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -577,8 +577,8 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) struct page *page; pgoff_t page_offset; - /* We don't use vmf->pgoff since that has the fake offset */ - page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT; + /* Offset to faulty address in the VMA. */ + page_offset = vmf->pgoff - vma->vm_pgoff; dma_resv_lock(shmem->base.resv, NULL); -- 2.47.3