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(unknown [IPv6:2a01:e0a:5e3:6100:2e0:4cff:fe03:d8c]) (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 627B817E13B5; Mon, 10 Nov 2025 15:27:51 +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 v6 01/11] drm/shmem-helper: Simplify page offset calculation in fault handler Date: Mon, 10 Nov 2025 15:27:36 +0100 Message-ID: <20251110142746.3490-2-loic.molinari@collabora.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251110142746.3490-1-loic.molinari@collabora.com> References: <20251110142746.3490-1-loic.molinari@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: CB99F180009 X-Stat-Signature: 73o8o9s9mod8op71s63hm5d8pjgkqjfs X-Rspam-User: X-HE-Tag: 1762784874-36118 X-HE-Meta: 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 j0oP7tQt Xj8bU0Wi8HKC0Am3FwDWyvXH5O68EgisQtUFJ+BBxVtu2avRlmgSsLzpExINFLL8Qpz3pSyz5hW74ilrU+7v0o4PK7UeDomhcu+uUoncRalgc35IUlGza7zc9VnxOsVCYyBENukIcJ5itsnSKTOXm71xshxfKXFrEJbJEV1nwNmpOmfw1WokKwgyma8XIE1o7ApQ3SB4uO9DxlF9UWpE3/4FdZ45wtR8XOuQCbJEjc4kk8R9Rf96BjKekNQowldUobXbXwzn60gMHK6LytDjPNlu/BOtiNXpKzx82QUNGXo3xtXcuZ4EhItZg2J+cM+pKOL3fHQS62T2fkCTRr3pZ7bGwXJlEfcWHCKbA9uEBJVx85R2l5rMFxCeqYxeNtDvZqoC3 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