From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C0A4DB661 for ; Mon, 6 Oct 2025 06:07:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759730876; cv=none; b=FAwKv8eHRT/3Ss+TgMfR1C3zzvaDksCnHyjOQkNpU7oXx64v6OD+eFrS9vaSs9i0XDNm8/J1JWvZglSOabeNfiA92W7Zi2ifdJtn8I0p86PUtKFSqegyii54B7Lg5oxasf8p1njttNYEVWyGXMLjYtIYVkGy2e6V6M8emO986pU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759730876; c=relaxed/simple; bh=wanpqYJKgkTOItfG6dUIGsO9Tb0evSs7UlMQBwxDWBM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kn0w+OjFIqtdDvIzuPZuf8+9zwMjhump9F7BKxkwvxmYOyySxhAaKMaI65BeC9IrfbwpVMHF8WRudwGyuFXnWBSZIVkjZkp+YlW0IuX2g3GcYyqwX/kHmcJ2A0ii3r36w++K8d9HmJ1fNL0Di9MzrLLmGk/f6Azq4mon9piKZmQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 E8227150C; Sun, 5 Oct 2025 23:07:45 -0700 (PDT) Received: from [10.163.66.9] (unknown [10.163.66.9]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EAE873F59E; Sun, 5 Oct 2025 23:07:51 -0700 (PDT) Message-ID: <4b513d32-7795-4998-98df-d398c3d5462a@arm.com> Date: Mon, 6 Oct 2025 11:37:48 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/dirty: Replace READ_ONCE() with pudp_get() To: Anshuman Khandual , linux-mm@kvack.org Cc: Andrew Morton , David Hildenbrand , linux-kernel@vger.kernel.org References: <20251006055214.1845342-1-anshuman.khandual@arm.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20251006055214.1845342-1-anshuman.khandual@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 06/10/25 11:22 am, Anshuman Khandual wrote: > Replace READ_ONCE() with a standard page table accessor i.e pudp_get() that > anyways defaults into READ_ONCE() in cases where platform does not override > > Cc: Andrew Morton > Cc: David Hildenbrand > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > mm/mapping_dirty_helpers.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c > index c193de6cb23a..737c407f4081 100644 > --- a/mm/mapping_dirty_helpers.c > +++ b/mm/mapping_dirty_helpers.c > @@ -149,7 +149,7 @@ static int wp_clean_pud_entry(pud_t *pud, unsigned long addr, unsigned long end, > struct mm_walk *walk) > { > #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD > - pud_t pudval = READ_ONCE(*pud); > + pud_t pudval = pudp_get(pud); > > /* Do not split a huge pud */ > if (pud_trans_huge(pudval)) { Talking about mm, why not also make changes for these READ_ONCE accesses in gup, hmm, memory, mprotect, sparse-vmemmap?