From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f51.google.com (mail-wg0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 180F96B0032 for ; Thu, 15 Jan 2015 03:58:17 -0500 (EST) Received: by mail-wg0-f51.google.com with SMTP id x12so13515357wgg.10 for ; Thu, 15 Jan 2015 00:58:16 -0800 (PST) Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com. [195.75.94.106]) by mx.google.com with ESMTPS id cu5si8256634wib.48.2015.01.15.00.58.15 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 15 Jan 2015 00:58:16 -0800 (PST) Received: from /spool/local by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 15 Jan 2015 08:58:15 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 24FA7219005E for ; Thu, 15 Jan 2015 08:57:41 +0000 (GMT) Received: from d06av05.portsmouth.uk.ibm.com (d06av05.portsmouth.uk.ibm.com [9.149.37.229]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t0F8wDCE60751942 for ; Thu, 15 Jan 2015 08:58:13 GMT Received: from d06av05.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t0F8wD6u009615 for ; Thu, 15 Jan 2015 01:58:13 -0700 From: Christian Borntraeger Subject: [PATCH 2/8] ppc/hugetlbfs: Replace ACCESS_ONCE with READ_ONCE Date: Thu, 15 Jan 2015 09:58:28 +0100 Message-Id: <1421312314-72330-3-git-send-email-borntraeger@de.ibm.com> In-Reply-To: <1421312314-72330-1-git-send-email-borntraeger@de.ibm.com> References: <1421312314-72330-1-git-send-email-borntraeger@de.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, xen-devel@lists.xenproject.org, linux-mm@kvack.org, Christian Borntraeger ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Change the ppc/hugetlbfs code to replace ACCESS_ONCE with READ_ONCE. Signed-off-by: Christian Borntraeger --- arch/powerpc/mm/hugetlbpage.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 5ff4e07..620d0ec 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -978,7 +978,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift */ pdshift = PUD_SHIFT; pudp = pud_offset(&pgd, ea); - pud = ACCESS_ONCE(*pudp); + pud = READ_ONCE(*pudp); if (pud_none(pud)) return NULL; @@ -990,7 +990,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift else { pdshift = PMD_SHIFT; pmdp = pmd_offset(&pud, ea); - pmd = ACCESS_ONCE(*pmdp); + pmd = READ_ONCE(*pmdp); /* * A hugepage collapse is captured by pmd_none, because * it mark the pmd none and do a hpte invalidate. -- 1.9.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org