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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 49202C83F17 for ; Fri, 18 Jul 2025 09:18:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XTswRIxHmGHQeVnB/f9odmxm7RsTWTBKCzGSB4iSFqo=; b=3V8HC1P290Sm2SNBf2b7JCETHl Y6S7v1RVL8KhUkToMrQqnb+DU61COcZqOKtmNHzV0lEaN7DgaeJh+u2e4LdFsXrzPLg9Eb/qVy0Lz pLFZE8JK0jRn2YZD/pXasH18rBMnkQYizrvY43F4osSIPFuP9WC8iW4KCaE/xIQXcWWOCbrTNm3FQ B+tP2r3ivYfCTgyc/Uu7JWVqpVWF6aiNH0gqCew+rX4qNdw3/54+8fQC45icaDKIAkWesdULJix5Y 12cYdLHarka2nQn3DAmPmYjPfU8Y3JuE8W/DDipkF4e5uAXGBoXeZtoN4y97DyIfWKyuGTz/Qym3j xBHCHtTA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uchEF-0000000C9dR-0FnM; Fri, 18 Jul 2025 09:18:07 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uch0J-0000000C7RS-3LLT for linux-arm-kernel@lists.infradead.org; Fri, 18 Jul 2025 09:03:45 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 09EBF1A32; Fri, 18 Jul 2025 02:03:36 -0700 (PDT) Received: from MacBook-Pro.blr.arm.com (unknown [10.164.18.51]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 53D8E3F66E; Fri, 18 Jul 2025 02:03:35 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org Cc: ryan.roberts@arm.com, david@redhat.com, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, vbabka@suse.cz, jannh@google.com, anshuman.khandual@arm.com, peterx@redhat.com, joey.gouly@arm.com, ioworker0@gmail.com, baohua@kernel.org, kevin.brodsky@arm.com, quic_zhenhuah@quicinc.com, christophe.leroy@csgroup.eu, yangyicong@hisilicon.com, linux-arm-kernel@lists.infradead.org, hughd@google.com, yang@os.amperecomputing.com, ziy@nvidia.com, Dev Jain Subject: [PATCH v5 5/7] mm: Split can_change_pte_writable() into private and shared parts Date: Fri, 18 Jul 2025 14:32:42 +0530 Message-Id: <20250718090244.21092-6-dev.jain@arm.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20250718090244.21092-1-dev.jain@arm.com> References: <20250718090244.21092-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250718_020343_909188_20CC593F X-CRM114-Status: GOOD ( 11.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In preparation for patch 6 and modularizing the code in general, split can_change_pte_writable() into private and shared VMA parts. No functional change intended. Suggested-by: Lorenzo Stoakes Signed-off-by: Dev Jain --- mm/mprotect.c | 50 ++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 36 insertions(+), 14 deletions(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index 4977f198168e..a1c7d8a4648d 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -40,11 +40,8 @@ #include "internal.h" -bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, - pte_t pte) +static bool maybe_change_pte_writable(struct vm_area_struct *vma, pte_t pte) { - struct page *page; - if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE))) return false; @@ -60,16 +57,32 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, if (userfaultfd_pte_wp(vma, pte)) return false; - if (!(vma->vm_flags & VM_SHARED)) { - /* - * Writable MAP_PRIVATE mapping: We can only special-case on - * exclusive anonymous pages, because we know that our - * write-fault handler similarly would map them writable without - * any additional checks while holding the PT lock. - */ - page = vm_normal_page(vma, addr, pte); - return page && PageAnon(page) && PageAnonExclusive(page); - } + return true; +} + +static bool can_change_private_pte_writable(struct vm_area_struct *vma, + unsigned long addr, pte_t pte) +{ + struct page *page; + + if (!maybe_change_pte_writable(vma, pte)) + return false; + + /* + * Writable MAP_PRIVATE mapping: We can only special-case on + * exclusive anonymous pages, because we know that our + * write-fault handler similarly would map them writable without + * any additional checks while holding the PT lock. + */ + page = vm_normal_page(vma, addr, pte); + return page && PageAnon(page) && PageAnonExclusive(page); +} + +static bool can_change_shared_pte_writable(struct vm_area_struct *vma, + pte_t pte) +{ + if (!maybe_change_pte_writable(vma, pte)) + return false; VM_WARN_ON_ONCE(is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte)); @@ -83,6 +96,15 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, return pte_dirty(pte); } +bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, + pte_t pte) +{ + if (!(vma->vm_flags & VM_SHARED)) + return can_change_private_pte_writable(vma, addr, pte); + + return can_change_shared_pte_writable(vma, pte); +} + static int mprotect_folio_pte_batch(struct folio *folio, pte_t *ptep, pte_t pte, int max_nr_ptes) { -- 2.30.2