From nobody Sun Feb 8 17:36:43 2026 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4FDA72C0F90; Fri, 14 Nov 2025 17:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763139797; cv=none; b=rp5z0XdYCEKzoQUzwiv5XFMXdIYzknIZfnucD8kt/iAueHoAJnkIC08tqtZfDEZ97g1bGIT7qlJ2PxFGLXqL05VoronOevW9J9s3UXAozgn1k1LUed6Y4SPyvBjSUQQQ/g1xB/vvdybteRVxvl5WlTrOUuTfJJhrClMjKtAD3Bg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763139797; c=relaxed/simple; bh=sQcBV/ZWlVLGeAwivyndjv3Kv+k/mZS823qVLbIeFmg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=VokhT2pNSKzLY457GkJWaGaWIiUET9146LJv/9QRHo9pdmDqOnXfJ9cpHqAj7vYVu8D2Q/e8i0F2GrWEC1EEyBNelkH+UHgJTktvgfNG/KlKBv2DzC4kdu+b5rWxHJ+Ej3E6DGUEi6qRcpudpYdcyPKxV58CV8ujxwiY9saVLNs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=kYKGbltQ; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="kYKGbltQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1763139788; bh=sQcBV/ZWlVLGeAwivyndjv3Kv+k/mZS823qVLbIeFmg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kYKGbltQKSPQa6YbnxxGn/A+cBP6YJyJu1PnpI/CJ7U9HId/69cWR0lhjhHn5tAVd VI2OKYdYcMbo2K/cisnj0ARnfDKJ/Eoy/uDBjI7idbD+lebXr3B1zPGhwV3qYXPT3v 9/JYtwfIt6nIuMjKBPQGSDG57MPrTlNGOuY4qXmxvGqJoX6gYh2GCTSOQpF5uL1AUd KT2BJRO4Bn0V5X8147srHtIp9ZglLJipIgxO7xadYuWUNgQpWmJCqL3ReDFsqT9okT uDbhhXk8Dm5a0P4pDsML+eRf3L0BIvjTviq6wh8PWF7hfBfBqZBT2wRIxmQpMc+/h/ MJK1qt+7Sp/0g== Received: from debian-rockchip-rock5b-rk3588.. (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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable For a fault at address addr, the page offset is page_offset =3D (vmf->address - vma->vm_start) >> PAGE_SHIFT =3D ((addr & PAGE_MASK) - vma->vm_start) >> PAGE_SHIFT =3D (addr - vma->vm_start) >> PAGE_SHIFT Since the faulty logical page offset based on VMA is vmf->pgoff =3D vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) We can slightly simplify the calculation using page_offset =3D vmf->pgoff - vma->vm_pgoff Signed-off-by: Lo=C3=AFc 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_g= em_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; =20 - /* We don't use vmf->pgoff since that has the fake offset */ - page_offset =3D (vmf->address - vma->vm_start) >> PAGE_SHIFT; + /* Offset to faulty address in the VMA (without the fake offset). */ + page_offset =3D vmf->pgoff - vma->vm_pgoff; =20 dma_resv_lock(shmem->base.resv, NULL); =20 --=20 2.47.3