From patchwork Tue Feb 24 02:28:05 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 5869031 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 7BB55BF440 for ; Tue, 24 Feb 2015 02:28:20 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8BC0820635 for ; Tue, 24 Feb 2015 02:28:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 229902062B for ; Tue, 24 Feb 2015 02:28:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752178AbbBXC2Q (ORCPT ); Mon, 23 Feb 2015 21:28:16 -0500 Received: from cantor2.suse.de ([195.135.220.15]:57942 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751712AbbBXC2P (ORCPT ); Mon, 23 Feb 2015 21:28:15 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 24E40ACA0; Tue, 24 Feb 2015 02:28:14 +0000 (UTC) Date: Tue, 24 Feb 2015 13:28:05 +1100 From: NeilBrown To: Thomas Gleixner , "Rafael J. Wysocki" Cc: linux-kernel@vger.kernel.org, GTA04 owners , linux-pm@vger.kernel.org, Kalle Jokiniemi Subject: [PATCH - RESEND] IRQ: don't suspend nested_thread irqs over system suspend. Message-ID: <20150224132805.385a56a5@notabene.brown> X-Mailer: Claws Mail 3.10.1-162-g4d0ed6 (GTK+ 2.24.25; x86_64-suse-linux-gnu) MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, T_TVD_MIME_EPI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Nested IRQs can only fire when the parent irq fires. So when the parent is suspended, there is no need to suspend the child irq. Suspending nested irqs can cause a problem is they are suspended or resumed in the wrong order. If an interrupt fires while the parent is active but the child is suspended, then the interrupt will not be acknowledged properly and so an interrupt storm can result. This is particularly likely if the parent is resumed before the child, and the interrupt was raised during suspend. Ensuring correct ordering would be possible, but it is simpler to just never suspend nested interrupts. Signed-off-by: NeilBrown --- This is a resend of a patch sent at the end of January 2015. Rafael seemed happy with it, but I receive no other response so I'm resending. Thanks, NeilBrown diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c index 3ca532592704..40cbcfb7fc43 100644 --- a/kernel/irq/pm.c +++ b/kernel/irq/pm.c @@ -118,6 +118,8 @@ void suspend_device_irqs(void) unsigned long flags; bool sync; + if (irq_settings_is_nested_thread(desc)) + continue; raw_spin_lock_irqsave(&desc->lock, flags); sync = suspend_device_irq(desc, irq); raw_spin_unlock_irqrestore(&desc->lock, flags); @@ -158,6 +160,8 @@ static void resume_irqs(bool want_early) if (!is_early && want_early) continue; + if (irq_settings_is_nested_thread(desc)) + continue; raw_spin_lock_irqsave(&desc->lock, flags); resume_irq(desc, irq);