From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 81113CA0FE1 for ; Fri, 22 Aug 2025 08:15:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B326E6B0172; Fri, 22 Aug 2025 04:15:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AE2586B0173; Fri, 22 Aug 2025 04:15:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9830F6B0174; Fri, 22 Aug 2025 04:15:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 7C9A16B0172 for ; Fri, 22 Aug 2025 04:15:23 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 43132C06B3 for ; Fri, 22 Aug 2025 08:15:23 +0000 (UTC) X-FDA: 83803683726.09.E8A5B88 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) by imf11.hostedemail.com (Postfix) with ESMTP id 14D774000C for ; Fri, 22 Aug 2025 08:15:20 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=samsung.com header.s=mail20170921 header.b=e4dvoXQd; spf=pass (imf11.hostedemail.com: domain of m.szyprowski@samsung.com designates 210.118.77.11 as permitted sender) smtp.mailfrom=m.szyprowski@samsung.com; dmarc=pass (policy=none) header.from=samsung.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755850521; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=gSgM5v5QN4mf4R9UjO3p9g49c5fElcblzx9rfuNpgCM=; b=3oDcOzq4LdYqRAI8C90bgvg+vNOk6kiHsGx6w6fdzNdXxpvfW+a9ARwG66GWlrersgld29 pPVppsvYfcueiJGQYXeZT2Colvyk4C/nef4aw9kz9/U5PnN+y+osEzvdvYOe6+IQtPZr+K TG7LHU3KH87xUlOSigaC+FZXdr4Qm2U= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755850521; a=rsa-sha256; cv=none; b=wq6aj6NAK/Sxp1WXziaJSMKvzqYYZpsD/tIzshlS4Vq5qDfIKDsAKhrH7QFeyQ25aCspOG CEHJJM5LkTh+NFCrEkbVH+GNZCH96WZ4LiaG5yRIkAOt4KZIqO2+UHNpGHZd3kphWkanm4 kpoFbaR749MUHNbbjB5QUUbdhoFQPgA= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=samsung.com header.s=mail20170921 header.b=e4dvoXQd; spf=pass (imf11.hostedemail.com: domain of m.szyprowski@samsung.com designates 210.118.77.11 as permitted sender) smtp.mailfrom=m.szyprowski@samsung.com; dmarc=pass (policy=none) header.from=samsung.com Received: from eucas1p2.samsung.com (unknown [182.198.249.207]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20250822081519euoutp01946853c37392c604dd0c3ef7d9f9864d~eCL6pnShX0804708047euoutp01V; Fri, 22 Aug 2025 08:15:19 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20250822081519euoutp01946853c37392c604dd0c3ef7d9f9864d~eCL6pnShX0804708047euoutp01V DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1755850519; bh=gSgM5v5QN4mf4R9UjO3p9g49c5fElcblzx9rfuNpgCM=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=e4dvoXQdSu6m2XApKflo9WPmqpXymYx8peucZKWnnidxwTqyyGT6vyRmLSZhDupfy UQS833Dv4xDvMpcINMnXzIPqm8717h4UDC2WHsJO8GSlXAIbIu/HM+EmSf5f03lk+1 DvviTyYYSXyxJn74yEGOVwAsfz9e64KnZWqZgVcw= Received: from eusmtip1.samsung.com (unknown [203.254.199.221]) by eucas1p1.samsung.com (KnoxPortal) with ESMTPA id 20250822081519eucas1p173966299ee7e4ed7e44e5668490c5bb1~eCL6VCjyQ0206902069eucas1p1F; Fri, 22 Aug 2025 08:15:19 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip1.samsung.com (KnoxPortal) with ESMTPA id 20250822081515eusmtip1e7bc345219f25d2646a53b4e40310c91~eCL2XTm3N1429714297eusmtip1U; Fri, 22 Aug 2025 08:15:14 +0000 (GMT) Message-ID: <8c4b0068-92be-427b-8bfc-9926eea6aa09@samsung.com> Date: Fri, 22 Aug 2025 10:15:14 +0200 MIME-Version: 1.0 User-Agent: Betterbird (Windows) Subject: Re: [PATCH RFC 23/35] scatterlist: disallow non-contigous page ranges in a single SG entry To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: 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 , 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 Content-Language: en-US From: Marek Szyprowski In-Reply-To: <20250821200701.1329277-24-david@redhat.com> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20250822081519eucas1p173966299ee7e4ed7e44e5668490c5bb1 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20250821200818eucas1p2c3df1e12eeba86a68679743d2f5929a8 X-EPHeader: CA X-CMS-RootMailID: 20250821200818eucas1p2c3df1e12eeba86a68679743d2f5929a8 References: <20250821200701.1329277-1-david@redhat.com> <20250821200701.1329277-24-david@redhat.com> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 14D774000C X-Stat-Signature: rqgjoc947pni5o73dkgsm8sgur9pb8g7 X-Rspam-User: X-HE-Tag: 1755850520-305094 X-HE-Meta: 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 3jtw8qnI LqOCW5VKMjHoKASBCHCJp0LNFI99VLqTV8LZdANwbpgy4w9i8Tw1BKnmqyNienQdqoWbI86esgfEkZQX/TCLEU9h3wE7esRSDw4DP 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: On 21.08.2025 22:06, David Hildenbrand wrote: > 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 > > struct scatterlist { > @@ -158,6 +159,7 @@ static inline void sg_assign_page(struct scatterlist *sg, 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_SIZE) / PAGE_SIZE)); > sg_assign_page(sg, page); > sg->offset = offset; > sg->length = 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; > } > > /** Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland