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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 7E3E717E12D4; Fri, 14 Nov 2025 18:03:07 +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 v9 01/11] drm/shmem-helper: Simplify page offset calculation in fault handler Date: Fri, 14 Nov 2025 18:02:52 +0100 Message-ID: <20251114170303.2800-2-loic.molinari@collabora.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251114170303.2800-1-loic.molinari@collabora.com> References: <20251114170303.2800-1-loic.molinari@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 5559980022 X-Stat-Signature: 8i4jyyzayzsj4cxxbz99b5pedse7x4zy X-Rspam-User: X-HE-Tag: 1763139791-348056 X-HE-Meta: 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 KI+X/Ib/ 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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