From patchwork Mon Oct 9 10:07:35 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Dufour X-Patchwork-Id: 823163 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3y9bhL4Xrbz9tXx for ; Mon, 9 Oct 2017 21:14:42 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3y9bhL3YL2zDrT9 for ; Mon, 9 Oct 2017 21:14:42 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=ldufour@linux.vnet.ibm.com; receiver=) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3y9bY01BjVzDr52 for ; Mon, 9 Oct 2017 21:08:20 +1100 (AEDT) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v99A7Tso055798 for ; Mon, 9 Oct 2017 06:08:18 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 2dfwecbrqk-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 09 Oct 2017 06:08:18 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 9 Oct 2017 11:08:08 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v99A87OE28049656; Mon, 9 Oct 2017 10:08:07 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EC25A52043; Mon, 9 Oct 2017 10:02:39 +0100 (BST) Received: from nimbus.lab.toulouse-stg.fr.ibm.com (unknown [9.145.51.101]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 4207E5203F; Mon, 9 Oct 2017 10:02:38 +0100 (BST) From: Laurent Dufour To: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov Subject: [PATCH v4 03/20] mm: Introduce pte_spinlock for FAULT_FLAG_SPECULATIVE Date: Mon, 9 Oct 2017 12:07:35 +0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1507543672-25821-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1507543672-25821-1-git-send-email-ldufour@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17100910-0040-0000-0000-000003E0C55E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17100910-0041-0000-0000-000025E24189 Message-Id: <1507543672-25821-4-git-send-email-ldufour@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-10-09_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710090147 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.24 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, npiggin@gmail.com, linux-mm@kvack.org, Tim Chen , haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When handling page fault without holding the mmap_sem the fetch of the pte lock pointer and the locking will have to be done while ensuring that the VMA is not touched in our back. So move the fetch and locking operations in a dedicated function. Signed-off-by: Laurent Dufour --- mm/memory.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 40dbf7efbcad..27f626c229f7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2451,6 +2451,13 @@ static inline void wp_page_reuse(struct vm_fault *vmf) pte_unmap_unlock(vmf->pte, vmf->ptl); } +static bool pte_spinlock(struct vm_fault *vmf) +{ + vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); + spin_lock(vmf->ptl); + return true; +} + static bool pte_map_lock(struct vm_fault *vmf) { vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); @@ -3788,8 +3795,8 @@ static int do_numa_page(struct vm_fault *vmf) * validation through pte_unmap_same(). It's of NUMA type but * the pfn may be screwed if the read is non atomic. */ - vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd); - spin_lock(vmf->ptl); + if (!pte_spinlock(vmf)) + return VM_FAULT_RETRY; if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) { pte_unmap_unlock(vmf->pte, vmf->ptl); goto out; @@ -3981,8 +3988,8 @@ static int handle_pte_fault(struct vm_fault *vmf) if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) return do_numa_page(vmf); - vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); - spin_lock(vmf->ptl); + if (!pte_spinlock(vmf)) + return VM_FAULT_RETRY; entry = vmf->orig_pte; if (unlikely(!pte_same(*vmf->pte, entry))) goto unlock;