From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757779Ab0JRVSI (ORCPT ); Mon, 18 Oct 2010 17:18:08 -0400 Received: from www.tglx.de ([62.245.132.106]:58921 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756050Ab0JRVSF (ORCPT ); Mon, 18 Oct 2010 17:18:05 -0400 Date: Mon, 18 Oct 2010 23:17:53 +0200 (CEST) From: Thomas Gleixner To: Yinghai Lu cc: Ingo Molnar , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86, irq: Check if irq is remapped before freeing irte In-Reply-To: Message-ID: References: <4CBCB274.7010108@kernel.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 18 Oct 2010, Thomas Gleixner wrote: > On Mon, 18 Oct 2010, Yinghai Lu wrote: > > > > Index: linux-2.6/drivers/pci/intr_remapping.c > > =================================================================== > > --- linux-2.6.orig/drivers/pci/intr_remapping.c > > +++ linux-2.6/drivers/pci/intr_remapping.c > > @@ -60,7 +60,7 @@ int get_irte(int irq, struct irte *entry > > unsigned long flags; > > int index; > > > > - if (!entry || !irq_iommu) > > + if (!entry || !irq_iommu || !irq_iommu->iommu) > > return -1; > > Hmm, why do we need this? This is only called from > ir_ioapic_set_affinity() and ir_msi_set_affinity(). > > We should never end up there when intr_remapping=off, right ? Thinking more about it, this check is actively bogus. The call sites do: struct irte irte; if (get_irte(irq, &irte)) return -1; So entry _CANNOT_ be NULL. And in fact we should change get_irte() to get_irte(struct irq_2_iommu *irq_iommu, struct irte *entry) The call site already knows about it. No need to lookup irq_iommu based on the irq number. Thanks, tglx