From patchwork Fri Mar 31 03:24:24 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhen Lei X-Patchwork-Id: 96339 Delivered-To: patch@linaro.org Received: by 10.140.89.233 with SMTP id v96csp537074qgd; Thu, 30 Mar 2017 20:26:59 -0700 (PDT) X-Received: by 10.98.152.219 with SMTP id d88mr699996pfk.153.1490930819545; Thu, 30 Mar 2017 20:26:59 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id l2si3727959pfl.11.2017.03.30.20.26.59; Thu, 30 Mar 2017 20:26:59 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932775AbdCaD03 (ORCPT + 20 others); Thu, 30 Mar 2017 23:26:29 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:5274 "EHLO dggrg01-dlp.huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S932296AbdCaD0Y (ORCPT ); Thu, 30 Mar 2017 23:26:24 -0400 Received: from 172.30.72.54 (EHLO DGGEML401-HUB.china.huawei.com) ([172.30.72.54]) by dggrg01-dlp.huawei.com (MOS 4.4.6-GA FastPath queued) with ESMTP id ALU41363; Fri, 31 Mar 2017 11:26:22 +0800 (CST) Received: from localhost (10.177.23.164) by DGGEML401-HUB.china.huawei.com (10.3.17.32) with Microsoft SMTP Server id 14.3.301.0; Fri, 31 Mar 2017 11:26:12 +0800 From: Zhen Lei To: Joerg Roedel , iommu , Robin Murphy , David Woodhouse , Sudeep Dutt , Ashutosh Dixit , linux-kernel CC: Zefan Li , Xinwei Hu , "Tianhong Ding" , Hanjun Guo , Zhen Lei Subject: [PATCH v2 6/7] iommu/iova: move the caculation of pad mask out of loop Date: Fri, 31 Mar 2017 11:24:24 +0800 Message-ID: <1490930665-9696-7-git-send-email-thunder.leizhen@huawei.com> X-Mailer: git-send-email 1.9.5.msysgit.0 In-Reply-To: <1490930665-9696-1-git-send-email-thunder.leizhen@huawei.com> References: <1490930665-9696-1-git-send-email-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.177.23.164] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.58DDCC5E.009E, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 07959a9bd08ef98cbe6d10fcb7567e45 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I'm not sure whether the compiler can optimize it, but move it out will be better. At least, it does not require lock protection. Signed-off-by: Zhen Lei --- drivers/iommu/iova.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) -- 2.5.0 diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 23abe84..68754e4 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -127,23 +127,16 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) *cached_node = rb_prev(&free->node); } -/* - * Computes the padding size required, to make the start address - * naturally aligned on the power-of-two order of its size - */ -static unsigned long -iova_get_pad_size(unsigned long size, unsigned long limit_pfn) -{ - return (limit_pfn + 1 - size) & (__roundup_pow_of_two(size) - 1); -} - static int __alloc_and_insert_iova_range(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn, struct iova *new, bool size_aligned) { struct rb_node *prev, *curr; unsigned long flags; - unsigned long pad_size = 0; + unsigned long pad_mask, pad_size = 0; + + if (size_aligned) + pad_mask = __roundup_pow_of_two(size) - 1; /* Walk the tree backwards */ spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); @@ -157,8 +150,13 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, else if (limit_pfn < curr_iova->pfn_hi) goto adjust_limit_pfn; else { + /* + * Computes the padding size required, to make the start + * address naturally aligned on the power-of-two order + * of its size + */ if (size_aligned) - pad_size = iova_get_pad_size(size, limit_pfn); + pad_size = (limit_pfn + 1 - size) & pad_mask; if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn) break; /* found a free slot */ }