From nobody Sun Feb 8 05:21:05 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 A85951547D2; Wed, 15 Oct 2025 15:30:29 +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=1760542231; cv=none; b=i1ARhRdIDN0o0TUJbKCjmWLPsgfVJEqtisxMHpGExnb9Rmg0Jzt+UhhC4LbtQmLgB7oXuNIu8aKaVytEdnK4lP+L2xDnZql615dssmh1TdWM7vB9DkGmvkNigpK+5TyJ+oHPfX/jsc1OItaAdKBybLwPk6pu9o40MMPWO+1O4Sc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760542231; 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=Z1Umb48aCU96uQ/dzRLsN8OnpgX1sBbu3+T2MBoPMukLi2GWqscf9efcac0MYyyLWQtOs7E1sxZiqNP1hKwHSwvRBrnWalWkH0IROxdg1+8NnXCsdCK62EgP5XjyN+cyE1Jf2tcVzkwogTS+Kl8t6pZqS/YXV0l8Sf5ZwPJYpK8= 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=VHdkIRj7; 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="VHdkIRj7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1760542227; bh=sQcBV/ZWlVLGeAwivyndjv3Kv+k/mZS823qVLbIeFmg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VHdkIRj7sg4VwSgsQanwXYtbK/UcvTe7EmUkEqqxHkXOqGzYygtHQ7zYKzTzN0BW0 DVlMfVVHuUVa4r3IHy86HYMx7KYMhmY6osKmaU4PMNbo+WlYSZefsYM7zb639o0aA/ ywmDIaSM8jVfaDD9GVr7KGmxiAMWOMnqZJI4O5IeZq7EcOlIu749ykkS7wXJ2xxBD4 Qb3umxLKhtjCGU/3anoP0khorYvpn7lF4YwEktiPC00IvTmS5qwmS1vf0pjGegIhmI cxfqel3TgrUMeNW//bU37J3wRhpV55lJlZy1Qeq8HVTySPa4FIJHJRhrHnwvayxp17 yopEYsaDRwSIA== 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 0BD0E17E1340; Wed, 15 Oct 2025 17:30:27 +0200 (CEST) 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 v4 01/13] drm/shmem-helper: Simplify page offset calculation in fault handler Date: Wed, 15 Oct 2025 17:30:05 +0200 Message-ID: <20251015153018.43735-2-loic.molinari@collabora.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251015153018.43735-1-loic.molinari@collabora.com> References: <20251015153018.43735-1-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