Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757116Ab3IZNBu (ORCPT ); Thu, 26 Sep 2013 09:01:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34405 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756695Ab3IZNBs (ORCPT ); Thu, 26 Sep 2013 09:01:48 -0400 Date: Thu, 26 Sep 2013 15:03:29 +0200 From: Alexander Gordeev To: Mark Lord Cc: Michael Ellerman , Benjamin Herrenschmidt , Tejun Heo , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "linux-pci@vger.kernel.org" , "linux-ide@vger.kernel.org" , Ingo Molnar , Joerg Roedel , Jan Beulich , Bjorn Helgaas , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2 2/6] PCI/MSI: Factor out pci_get_msi_cap() interface Message-ID: <20130926130328.GD16774@dhcp-26-207.brq.redhat.com> References: <20130905185440.GA13175@dhcp-26-207.brq.redhat.com> <20130905200608.GA3846@htj.dyndns.org> <20130906160621.GF22763@mtj.dyndns.org> <20130906233205.GF12956@google.com> <20130909152044.GA24962@dhcp-26-207.brq.redhat.com> <20130916102210.GA14102@dhcp-26-207.brq.redhat.com> <20130917143022.GA7707@concordia> <20130918094759.GA2353@dhcp-26-207.brq.redhat.com> <52442975.9000603@start.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52442975.9000603@start.ca> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1132 Lines: 24 On Thu, Sep 26, 2013 at 08:32:53AM -0400, Mark Lord wrote: > On 13-09-18 05:48 AM, Alexander Gordeev wrote: > > The last pattern makes most of sense to me and could be updated with a more > > clear sequence - a call to (bit modified) pci_msix_table_size() followed > > by a call to pci_enable_msix(). I think this pattern can effectively > > supersede the currently recommended "loop" practice. > > The loop is still necessary, because there's a race between those two calls, > so that pci_enable_msix() can still fail due to lack of MSIX slots. Moreover, the existing loop pattern is racy and could fail just as easily ;) But (1) that is something drivers should expect and (2) there is basically nothing to race against - that is probably the reason it has not been a problem for pSeries. So I think we should not care about this. -- Regards, Alexander Gordeev agordeev@redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/