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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 12C5017E127F; Mon, 10 Nov 2025 16:50:07 +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 v7 01/11] drm/shmem-helper: Simplify page offset calculation in fault handler Date: Mon, 10 Nov 2025 16:49:49 +0100 Message-ID: <20251110155000.2936-2-loic.molinari@collabora.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251110155000.2936-1-loic.molinari@collabora.com> References: <20251110155000.2936-1-loic.molinari@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: B62984000D X-Stat-Signature: 9mnukudzzb9wi59tjon9xiy1qt5sa199 X-HE-Tag: 1762789810-986613 X-HE-Meta: U2FsdGVkX18lpdyJ/IOuV5u0r1zjOYNbwI2IVDIuiTckRZoc0fX3T5fY3eJSmDa3XahkiTRyoYWsKSOY1qQrYugBmI27CfPMrdjFmCzIFvrYS9WZzJyow9CzZYXwl72OQ6AQc/fi4oNvKeLW3E0Q5rjKJx6tV8czLpaoaTtpHe7H0E6IuLyNCuPiSg2krIyIVdgUsmN6TzdfDwl+WVWgRw9HdhhFzclLVaPJrqDe9Nff54tc2Bu/Y5JRpwt41b0JPW5ldKQblMVz4ujWiIIJVvhvzPLdOch4yCqDLQxFc8RU7e99BkB2wm/sNdDylAETRYK+to+f3W1JcZW5N0myQUgkcSRvAFp2B8nOOu/KImiLzwabG5lPNMg9kIZ5kuo1I5YQ8gILeok1Bp/K4iCu6eDiGcmn0G+5BSvgqjJyc+hC44FNgdI5H38YRj/ZrWlVu+x+wLE0+67A4dBZrliEGAtqSYJ39fJdLPhwsGGGkyW1kSF1bfSwkLh908iqENJHX5qhyzzClVUHX7dvVRJ2GPxMuAZamxIh9hcSUSYhOctEW3i/E31kR8/gXjz1ptiLGeB2bB+8LrZPRejW/E+HaHgYs6S6b2TF13Cny7P4R5Goo68JZ7zVcrKI8lYrFcoeL/HV7tR4+ljoWHZoq1c0nzBpBtOFUPFy3a8Ko+wbX2Nyygg+VF/w+vAq7Zk2fnAcDgFfdYGAMyGMDEIxFSg3vFja04cdtjZ0zPK5k24j1LQG4/9NbSWitB8F9WnRuiOY1V69NIP+K9ysF6k+rvUjB338FvZOoRg6dvRkcEJajbLXFPp4kpgIZ6EZ4bKkCQEQoK3njbGenaOGV8rwvSqXgyWkHB00pixRZR/pVi9GiVd1mm8LqHvBFuuL3nslrtGdS6VRmNRkayAXm9F7HKfJOOY0ElqpCMxBkckHalzRPvQQYr36eGIB5pRZZC3syLC8ofA54WgSqugrFNpPDpk OiM7ZCp4 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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: 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 Signed-off-by: Loïc Molinari --- 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..be89be1c804c 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 (without the fake offset). */ + page_offset = vmf->pgoff - vma->vm_pgoff; dma_resv_lock(shmem->base.resv, NULL); -- 2.47.3