From nobody Sat Oct 4 01:39:02 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 4E66F36CC9F for ; Thu, 21 Aug 2025 20:08:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755806897; cv=none; b=ZgH8areGyzxkNOIH92MLpNseJb1ccRFTEJfJ9HWAcq6EhimOvS1COUDl3yK+fVSEnOKSEx8D269f1BbgzXz2WaZr1mnFQplSQSiyJSaxgwqI9J5R0tohlmLGBaC4pVLdlTYUWXJHMtiTibSWHJHpyuplY2tB4xeju/XnIeLMRw4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755806897; c=relaxed/simple; bh=kURokXQjB5Kuo7a6U8usTL1aQ1tfaOTG2Bf9aj2NBoo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qGpqePNEOsOgo8CVtPszDmo05IfohZrnOptARl3LwCHhINcFmgze3lOMU5nDarFc4RR2MkwEaLQrCxDy9dNeTbuoG4WJpGhUAvx/Q6OyFDTAc0jiqkrxSqhbxFVAwDny4HqMT6hT//l5OKjFc4S83YH0+HCH16jyvxxP+pKoZRY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Khicoxdz; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Khicoxdz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755806894; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NKFS9/TuG2v9AIcAoooIJr3bGKW6zmP0XL+5izT5Y+4=; b=KhicoxdzduubvKuf9Iix+KNDtDzlxsA85V/w/CkCqx1xtIvlyjeP3gOZ/UnD/kHm56z7up eS44Wa9teIG8fACDAtSRj0kPBZVX2cqe191Dx4vfjIoobrYjhQVYZW022ea1CcbPdqagcY qnSL7AEaR1rOqyOpAnE/tpK//DFlKbQ= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-589-mg9DEy5qOv2QYcKCzi-7Cw-1; Thu, 21 Aug 2025 16:08:13 -0400 X-MC-Unique: mg9DEy5qOv2QYcKCzi-7Cw-1 X-Mimecast-MFC-AGG-ID: mg9DEy5qOv2QYcKCzi-7Cw_1755806892 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-45a1b05d251so7744135e9.1 for ; Thu, 21 Aug 2025 13:08:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755806892; x=1756411692; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=NKFS9/TuG2v9AIcAoooIJr3bGKW6zmP0XL+5izT5Y+4=; b=VlZKIj7+lxptiCokNgjKj1D3b5zNbAMWcqotdmZZiRvZKRLS1WN8ANVXNKmZ1lTtA5 tcrqiQum/wk1cMeC9XZejUGXs7F3rUkex+eON7dl33LrWR5SxwgveEJk78AYGCMMsaV5 wFRSFVKme5vtHu/Vs0+wIBZEeclLxYMO5Iv5z1S97/iK41JeuEuqpLyUU2zRhLLbgq9r VN3r+hABJozWHTv+MkbXaSyRnsTaW6MjHcTpLfUg1XfKPvxrpXuhmk2RfCdANbEysjgb Ao2KjRAnXqvD+JfVgIwRtsOXydmjx/uNcvWXkHzGWR9PTUPfzMprYui2xfI4LxOs3HA0 +wIg== X-Gm-Message-State: AOJu0YwWAQwOvH6UFhhNPYRBpeG968bwLWvsDsGU6YCLMcbfPld/Fjex b+qyfsc7KM2GPwX2jwS/qLLFviqqtqFssvQj+skHs4pkSeuwk0t6Sars1iMqPXICXTWj/qRHyHu fioRzI8LFxOkxm07e7W5CRffI2Y0mCON2qINrj2fERHrRu2sXVHqZ+DMW2CDntiOsLh5PB5q1Zv nX0Mt/4G9VaDMcrwpx1trq4rI82VriEtU8bGZ+QwaxBpgWUrj6 X-Gm-Gg: ASbGncuzcS8JGSSNl0lLzlx5kzzscU5t1eCBHxMMFRPlqroHD1PjfknMBQMeTaYC7UA 76jnNoUhSI/6L7PYhBXZg4az91otWgaxHJXGZYHX2rFPnL8xuijsr2EPbrfAYXoJjMQ6pUnr8de SbsIPhuZpQzP4m292uq7ZKlIJqSLJytJTRVEzwVfPsGsGd/CUoQe9j2RTFXXbzcG4UB//N3PzYQ LWCgcV7gjj/WLuLrPpIfvfGnVFlqdp3q596+1Sl+UshqSJPTIrYMVDw9rYqj2EaQHWlZH/+Bhwz fgtXFxg0ZKlnFx3ksuJzLinHNsNU1FfHYDMRHVWoVjMQuQlst1g0WcvycurNdJwDaQWpJyeVcbV dvaeJP6xtHFijwl5xBVNi6g== X-Received: by 2002:a05:600c:1f1a:b0:45b:43cc:e557 with SMTP id 5b1f17b1804b1-45b517cbee2mr2552965e9.34.1755806891874; Thu, 21 Aug 2025 13:08:11 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE/z26sBz7JGLAktk/cnLNnmvA2KmHoRy5M1TseKC0NpCNohvOWfWbiwnk6fyruz4Gv4BdEig== X-Received: by 2002:a05:600c:1f1a:b0:45b:43cc:e557 with SMTP id 5b1f17b1804b1-45b517cbee2mr2552235e9.34.1755806891155; Thu, 21 Aug 2025 13:08:11 -0700 (PDT) Received: from localhost (p200300d82f26ba0008036ec5991806fd.dip0.t-ipconnect.de. [2003:d8:2f26:ba00:803:6ec5:9918:6fd]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3c0748797acsm12277591f8f.10.2025.08.21.13.08.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Aug 2025 13:08:10 -0700 (PDT) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, "Liam R. Howlett" , Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Lorenzo Stoakes , Marco Elver , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan Subject: [PATCH RFC 23/35] scatterlist: disallow non-contigous page ranges in a single SG entry Date: Thu, 21 Aug 2025 22:06:49 +0200 Message-ID: <20250821200701.1329277-24-david@redhat.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250821200701.1329277-1-david@redhat.com> References: <20250821200701.1329277-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The expectation is that there is currently no user that would pass in non-contigous page ranges: no allocator, not even VMA, will hand these out. The only problematic part would be if someone would provide a range obtained directly from memblock, or manually merge problematic ranges. If we find such cases, we should fix them to create separate SG entries. Let's check in sg_set_page() that this is really the case. No need to check in sg_set_folio(), as pages in a folio are guaranteed to be contiguous. We can now drop the nth_page() usage in sg_page_iter_page(). Signed-off-by: David Hildenbrand Acked-by: Marek Szyprowski --- include/linux/scatterlist.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 6f8a4965f9b98..8196949dfc82c 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -6,6 +6,7 @@ #include #include #include +#include #include =20 struct scatterlist { @@ -158,6 +159,7 @@ static inline void sg_assign_page(struct scatterlist *s= g, struct page *page) static inline void sg_set_page(struct scatterlist *sg, struct page *page, unsigned int len, unsigned int offset) { + VM_WARN_ON_ONCE(!page_range_contiguous(page, ALIGN(len + offset, PAGE_SIZ= E) / PAGE_SIZE)); sg_assign_page(sg, page); sg->offset =3D offset; sg->length =3D len; @@ -600,7 +602,7 @@ void __sg_page_iter_start(struct sg_page_iter *piter, */ static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) { - return nth_page(sg_page(piter->sg), piter->sg_pgoffset); + return sg_page(piter->sg) + piter->sg_pgoffset; } =20 /** --=20 2.50.1