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,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham 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 A9991C10F14 for ; Mon, 8 Apr 2019 19:15:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 717DA20879 for ; Mon, 8 Apr 2019 19:15:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554750906; bh=XP8f6UkErQBti+a6Kf6jSIfBEuoaOPaxDWYr0P9+J8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=OKkR+ndQoPyMpZkyCpqnxLo4NQlTTaeWrxgzc5OQmadgOZgN3TmuZow97lGmUSSee nNMkVjP+bu9j+NljHZH+wvM8+l0BwzVfVSvC8BiBsn/LCE1SwTdnOm2QoPou1DItsw VxW/Hb/n6pkT306zbUjo/cgsrRWhfzjLzHaaoXiM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729081AbfDHTPF (ORCPT ); Mon, 8 Apr 2019 15:15:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:45524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728820AbfDHTOj (ORCPT ); Mon, 8 Apr 2019 15:14:39 -0400 Received: from tzanussi-mobl.hsd1.il.comcast.net (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6E08F21906; Mon, 8 Apr 2019 19:14:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554750878; bh=XP8f6UkErQBti+a6Kf6jSIfBEuoaOPaxDWYr0P9+J8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=iY/XJHTTsl4atbrhZB7NMhWahIxIphYE0ccmVNDfOditqsQn5JiAgSonGlQShDiS0 paFDkE/ea0pSK22N5geIYzy+1m5bOOHfwwL+07i9ABXr8mJrVSrQGOKw9oKJ4wzhCX BaV/H9Qmy58ntVo0AxfDBr4S/pthXK/VtoaisYiE= From: Tom Zanussi To: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Cc: rostedt@goodmis.org, tglx@linutronix.de, C.Emde@osadl.org, jkacur@redhat.com, bigeasy@linutronix.de, daniel.wagner@siemens.com, julia@ni.com, amartin@nvidia.com Subject: [PATCH 12/13] powerpc/pseries/iommu: Use a locallock instead local_irq_save() Date: Mon, 8 Apr 2019 14:14:14 -0500 Message-Id: X-Mailer: git-send-email 2.14.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14.109-rt58-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior [ Upstream commit 5c1b4cd70e2ca0c81038b65babe6dc66086322e0 ] The locallock protects the per-CPU variable tce_page. The function attempts to allocate memory while tce_page is protected (by disabling interrupts). Use local_irq_save() instead of local_irq_disable(). Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Tom Zanussi --- arch/powerpc/platforms/pseries/iommu.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 7c181467d0ad..4bd046492c60 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include #include @@ -213,6 +214,7 @@ static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum, } static DEFINE_PER_CPU(__be64 *, tce_page); +static DEFINE_LOCAL_IRQ_LOCK(tcp_page_lock); static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long npages, unsigned long uaddr, @@ -233,7 +235,8 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, direction, attrs); } - local_irq_save(flags); /* to protect tcep and the page behind it */ + /* to protect tcep and the page behind it */ + local_lock_irqsave(tcp_page_lock, flags); tcep = __this_cpu_read(tce_page); @@ -244,7 +247,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, tcep = (__be64 *)__get_free_page(GFP_ATOMIC); /* If allocation fails, fall back to the loop implementation */ if (!tcep) { - local_irq_restore(flags); + local_unlock_irqrestore(tcp_page_lock, flags); return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr, direction, attrs); } @@ -278,7 +281,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum, tcenum += limit; } while (npages > 0 && !rc); - local_irq_restore(flags); + local_unlock_irqrestore(tcp_page_lock, flags); if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) { ret = (int)rc; @@ -436,13 +439,14 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn, u64 rc = 0; long l, limit; - local_irq_disable(); /* to protect tcep and the page behind it */ + /* to protect tcep and the page behind it */ + local_lock_irq(tcp_page_lock); tcep = __this_cpu_read(tce_page); if (!tcep) { tcep = (__be64 *)__get_free_page(GFP_ATOMIC); if (!tcep) { - local_irq_enable(); + local_unlock_irq(tcp_page_lock); return -ENOMEM; } __this_cpu_write(tce_page, tcep); @@ -488,7 +492,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn, /* error cleanup: caller will clear whole range */ - local_irq_enable(); + local_unlock_irq(tcp_page_lock); return rc; } -- 2.14.1