From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933470AbcHDMUA (ORCPT ); Thu, 4 Aug 2016 08:20:00 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:32091 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933297AbcHDMT6 (ORCPT ); Thu, 4 Aug 2016 08:19:58 -0400 X-IBM-Helo: d06dlp03.portsmouth.uk.ibm.com X-IBM-MailFrom: rppt@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: Mike Rapoport To: Andrea Arcangeli Cc: Hugh Dickins , Pavel Emelyanov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mike Rapoport Subject: [PATCH 3/7] userfaultfd: shmem: introduce vma_is_shmem Date: Thu, 4 Aug 2016 11:14:14 +0300 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1470298458-9925-1-git-send-email-rppt@linux.vnet.ibm.com> References: <1470298458-9925-1-git-send-email-rppt@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16080408-0032-0000-0000-000001F5E746 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16080408-0033-0000-0000-00001C42E23A Message-Id: <1470298458-9925-4-git-send-email-rppt@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-08-04_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608040093 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently userfault relies on vma_is_anonymous and vma_is_hugetlb to ensure compatibility of a VMA with userfault. Introduction of vma_is_shmem allows detection if tmpfs backed VMAs, so that they may be used with userfaultfd. Current implementation presumes usage of vma_is_shmem only by slow path routines in userfaultfd, therefore the vma_is_shmem is not made inline to leave the few remaining free bits in vm_flags. Signed-off-by: Mike Rapoport --- include/linux/mm.h | 10 ++++++++++ mm/shmem.c | 5 +++++ 2 files changed, 15 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1dedeb8..7a20398 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1343,6 +1343,16 @@ static inline bool vma_is_anonymous(struct vm_area_struct *vma) return !vma->vm_ops; } +#ifdef CONFIG_SHMEM +/* + * The vma_is_shmem is not inline because it is used only by slow + * paths in userfault. + */ +bool vma_is_shmem(struct vm_area_struct *vma); +#else +static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; } +#endif + static inline int stack_guard_page_start(struct vm_area_struct *vma, unsigned long addr) { diff --git a/mm/shmem.c b/mm/shmem.c index fcf560c..881b7a0 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -194,6 +194,11 @@ static const struct inode_operations shmem_dir_inode_operations; static const struct inode_operations shmem_special_inode_operations; static const struct vm_operations_struct shmem_vm_ops; +bool vma_is_shmem(struct vm_area_struct *vma) +{ + return vma->vm_ops == &shmem_vm_ops; +} + static LIST_HEAD(shmem_swaplist); static DEFINE_MUTEX(shmem_swaplist_mutex); -- 1.9.1