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 X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3532FC4360F for ; Tue, 2 Apr 2019 21:00:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F29CE20674 for ; Tue, 2 Apr 2019 21:00:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="zHZtVFnZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726477AbfDBVAe (ORCPT ); Tue, 2 Apr 2019 17:00:34 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:56180 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725822AbfDBVAe (ORCPT ); Tue, 2 Apr 2019 17:00:34 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x32Kd5We164028; Tue, 2 Apr 2019 20:44:21 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2018-07-02; bh=S3/NdFYbeXH44L9JBwqlhAYuzDTUjFxD7HwZ/en50So=; b=zHZtVFnZgKoe6ZZd0qgP5F20qgLYeOWz6WFuuVG1k0+N66MfV1nudJiuz+2DI13M9n+/ o8CI9whu2KiVn5rsBvVo65JdlCfmh/T4jcsa/xM75AbqoeT7a4yrN2L2Bng8UYCQ6a2H De5IK40aPpSq6rT8IeBkUYHuDbtluEkDJy2L7Dltwn9fOJZ6KxL0Rk012ZdOtvzjspr1 ZzGaDPdeUr4ec142YXkU37CGcy1HoStLQN7kJRtmodw6pDGhK5iwrUlP8utTFopsOkcs B4H4S1vHoByx7sZUZwJ2bDnQ8wcEYq95jACbPC/r64EKK7ZZzW4zat4swwLjYtWQhc+g bA== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2120.oracle.com with ESMTP id 2rj0dnm0bj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 02 Apr 2019 20:44:21 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x32KfGOl064850; Tue, 2 Apr 2019 20:42:21 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 2rm8f4yjyv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 02 Apr 2019 20:42:20 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x32KgJlj031428; Tue, 2 Apr 2019 20:42:19 GMT Received: from localhost.localdomain (/73.60.114.248) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 02 Apr 2019 13:42:19 -0700 From: Daniel Jordan To: akpm@linux-foundation.org Cc: daniel.m.jordan@oracle.com, Alexey Kardashevskiy , Alex Williamson , Christoph Lameter , Davidlohr Bueso , linux-mm@kvack.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/6] vfio/spapr_tce: drop mmap_sem now that locked_vm is atomic Date: Tue, 2 Apr 2019 16:41:55 -0400 Message-Id: <20190402204158.27582-4-daniel.m.jordan@oracle.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190402204158.27582-1-daniel.m.jordan@oracle.com> References: <20190402204158.27582-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9215 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=29 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904020138 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9215 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=29 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904020138 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With locked_vm now an atomic, there is no need to take mmap_sem as writer. Delete and refactor accordingly. Signed-off-by: Daniel Jordan Cc: Alexey Kardashevskiy Cc: Alex Williamson Cc: Andrew Morton Cc: Christoph Lameter Cc: Davidlohr Bueso Cc: Cc: Cc: --- drivers/vfio/vfio_iommu_spapr_tce.c | 36 ++++++++++++----------------- 1 file changed, 15 insertions(+), 21 deletions(-) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index e7d787e5d839..7675a3b28410 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -36,8 +36,9 @@ static void tce_iommu_detach_group(void *iommu_data, static long try_increment_locked_vm(struct mm_struct *mm, long npages) { - long ret = 0, lock_limit; + long ret = 0; s64 locked; + unsigned long lock_limit; if (WARN_ON_ONCE(!mm)) return -EPERM; @@ -45,39 +46,32 @@ static long try_increment_locked_vm(struct mm_struct *mm, long npages) if (!npages) return 0; - down_write(&mm->mmap_sem); - locked = atomic64_read(&mm->locked_vm) + npages; + locked = atomic64_add_return(npages, &mm->locked_vm); lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) + if (locked > lock_limit && !capable(CAP_IPC_LOCK)) { ret = -ENOMEM; - else - atomic64_add(npages, &mm->locked_vm); - - pr_debug("[%d] RLIMIT_MEMLOCK +%ld %ld/%ld%s\n", current->pid, - npages << PAGE_SHIFT, - atomic64_read(&mm->locked_vm) << PAGE_SHIFT, - rlimit(RLIMIT_MEMLOCK), - ret ? " - exceeded" : ""); + atomic64_sub(npages, &mm->locked_vm); + } - up_write(&mm->mmap_sem); + pr_debug("[%d] RLIMIT_MEMLOCK +%ld %lld/%lu%s\n", current->pid, + npages << PAGE_SHIFT, locked << PAGE_SHIFT, + lock_limit, ret ? " - exceeded" : ""); return ret; } static void decrement_locked_vm(struct mm_struct *mm, long npages) { + s64 locked; + if (!mm || !npages) return; - down_write(&mm->mmap_sem); - if (WARN_ON_ONCE(npages > atomic64_read(&mm->locked_vm))) - npages = atomic64_read(&mm->locked_vm); - atomic64_sub(npages, &mm->locked_vm); - pr_debug("[%d] RLIMIT_MEMLOCK -%ld %ld/%ld\n", current->pid, - npages << PAGE_SHIFT, - atomic64_read(&mm->locked_vm) << PAGE_SHIFT, + locked = atomic64_sub_return(npages, &mm->locked_vm); + WARN_ON_ONCE(locked < 0); + pr_debug("[%d] RLIMIT_MEMLOCK -%ld %lld/%lu\n", current->pid, + npages << PAGE_SHIFT, locked << PAGE_SHIFT, rlimit(RLIMIT_MEMLOCK)); - up_write(&mm->mmap_sem); } /* -- 2.21.0