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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D2FA1CA0FF7 for ; Wed, 27 Aug 2025 22:11:43 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3463610E908; Wed, 27 Aug 2025 22:11:43 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="hRk7UZ0j"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4731C10E908 for ; Wed, 27 Aug 2025 22:11:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756332700; 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=J4GDJdCQl51NuSKZxl+9iTiOXWhrOYbM3n+02Irtvfk=; b=hRk7UZ0jPcMlFIXNh72+z7xjIYD79DhnoeA0WRydEkRWrr39ZCFP34cMn/gXfGpSarSH2Z DCBb6vY2ORxvclWpjMlUQLaRduELuKsmsMygXrvDmnzUUAzohGgaQaFqqt5ODrSZjfO0eO Y2rzcFsguHOsHKEJgy3ayRA72qByu0I= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-581-9TdTk-QAOCyo3sfI9-0djQ-1; Wed, 27 Aug 2025 18:11:36 -0400 X-MC-Unique: 9TdTk-QAOCyo3sfI9-0djQ-1 X-Mimecast-MFC-AGG-ID: 9TdTk-QAOCyo3sfI9-0djQ_1756332692 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F1280180028E; Wed, 27 Aug 2025 22:11:31 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.22.80.195]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 78E0330001A1; Wed, 27 Aug 2025 22:11:16 +0000 (UTC) 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 v1 33/36] mm/gup: drop nth_page() usage in unpin_user_page_range_dirty_lock() Date: Thu, 28 Aug 2025 00:01:37 +0200 Message-ID: <20250827220141.262669-34-david@redhat.com> In-Reply-To: <20250827220141.262669-1-david@redhat.com> References: <20250827220141.262669-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" There is the concern that unpin_user_page_range_dirty_lock() might do some weird merging of PFN ranges -- either now or in the future -- such that PFN range is contiguous but the page range might not be. Let's sanity-check for that and drop the nth_page() usage. Signed-off-by: David Hildenbrand --- mm/gup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index 89ca0813791ab..c24f6009a7a44 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -237,7 +237,7 @@ void folio_add_pin(struct folio *folio) static inline struct folio *gup_folio_range_next(struct page *start, unsigned long npages, unsigned long i, unsigned int *ntails) { - struct page *next = nth_page(start, i); + struct page *next = start + i; struct folio *folio = page_folio(next); unsigned int nr = 1; @@ -342,6 +342,9 @@ EXPORT_SYMBOL(unpin_user_pages_dirty_lock); * "gup-pinned page range" refers to a range of pages that has had one of the * pin_user_pages() variants called on that page. * + * The page range must be truly contiguous: the page range corresponds + * to a contiguous PFN range and all pages can be iterated naturally. + * * For the page ranges defined by [page .. page+npages], make that range (or * its head pages, if a compound page) dirty, if @make_dirty is true, and if the * page range was previously listed as clean. @@ -359,6 +362,8 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages, struct folio *folio; unsigned int nr; + VM_WARN_ON_ONCE(!page_range_contiguous(page, npages)); + for (i = 0; i < npages; i += nr) { folio = gup_folio_range_next(page, npages, i, &nr); if (make_dirty && !folio_test_dirty(folio)) { -- 2.50.1