From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760442Ab0FQRsK (ORCPT ); Thu, 17 Jun 2010 13:48:10 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:48652 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760361Ab0FQRsG (ORCPT >); Thu, 17 Jun 2010 13:48:06 -0400 Date: Thu, 17 Jun 2010 13:46:22 -0400 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: "linux-kernel@vger.kernel.org" , "jeremy@goop.org" , "xen-devel@lists.xensource.com" , "ddutile@redhat.com" , "sheng@linux.intel.com" Subject: Re: [Xen-devel] [PATCH 12/12] Unplug emulated disks and nics Message-ID: <20100617174622.GB17523@phenom.dumpdata.com> References: <1275570645-27189-1-git-send-email-stefano.stabellini@eu.citrix.com> <1275570645-27189-12-git-send-email-stefano.stabellini@eu.citrix.com> <20100614212017.GA8600@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-12-10) X-Auth-Type: Internal IP X-Source-IP: acsinet15.oracle.com [141.146.126.227] X-CT-RefId: str=0001.0A090206.4C1A5FC6.0046:SCFMA922111,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 17, 2010 at 04:42:14PM +0100, Stefano Stabellini wrote: > On Mon, 14 Jun 2010, Konrad Rzeszutek Wilk wrote: > > > +#if (defined(CONFIG_XEN_NETDEV_FRONTEND) || \ > > > + defined(CONFIG_XEN_NETDEV_FRONTEND_MODULE)) && \ > > > + (defined(CONFIG_XEN_PLATFORM_PCI) || \ > > > + defined(CONFIG_XEN_PLATFORM_PCI_MODULE)) > > > + printk(KERN_INFO "Netfront and the Xen platform PCI driver have " > > > + "been compiled for this kernel: unplug emulated NICs.\n"); > > > + xen_emul_unplug |= XEN_UNPLUG_ALL_NICS; > > > +#endif > > > +#if (defined(CONFIG_XEN_BLKDEV_FRONTEND) || \ > > > + defined(CONFIG_XEN_BLKDEV_FRONTEND_MODULE)) && \ > > > + (defined(CONFIG_XEN_PLATFORM_PCI) || \ > > > + defined(CONFIG_XEN_PLATFORM_PCI_MODULE)) > > > + printk(KERN_INFO "Blkfront and the Xen platform PCI driver have " > > > + "been compiled for this kernel: unplug emulated disks.\n" > > > + "You might have to change the root device\n" > > > + "from /dev/hd[a-d] to /dev/xvd[a-d]\n" > > > + "in your root= kernel command line option\n"); > > > + xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS; > > > +#endif > > > > Wow. Can you move those checks to the header file and make it deal with > > the #ifdef and setting of xen_emul_unplug? > > > > I tried, but it didn't improve the elegance of the code, mainly because I > want to keep the printk in place, so the code would look very much like > this, but instead of being in platform-pci-unplug.c would be in > platform_pci.h. If was thinking of something like this in the header file: int xen_must_unplug_nics() { #if (defined(CONFIG_XEN_NETDEV_FRONTEND) || \ defined(CONFIG_XEN_NETDEV_FRONTEND_MODULE)) && \ (defined(CONFIG_XEN_PLATFORM_PCI) || \ defined(CONFIG_XEN_PLATFORM_PCI_MODULE)) return 1; #else return 0; } and then your code would be: if (xen_must_unplug_nics()) { printk(".. blah blah "); xen_emul_unplug |- XEN_unPLIG_ALL_NICS; } and similar for the IDE disks. > > > > > + } > > > + /* Now unplug the emulated devices */ > > > + if (xen_platform_pci_enabled && !(xen_emul_unplug & XEN_UNPLUG_IGNORE)) > > > + outw(xen_emul_unplug, XEN_IOPORT_UNPLUG); > > > +} > > > + > > > +static int __init parse_xen_emul_unplug(char *arg) > > > +{ > > > + char *p, *q; > > > + > > > + for (p = arg; p; p = q) { > > > + q = strchr(arg, ','); > > > + if (q) > > > + *q++ = '\0'; > > > + if (!strcmp(p, "all")) > > > + xen_emul_unplug |= XEN_UNPLUG_ALL; > > > > strncmp.. > > > > is it really needed considering that we know that both strings are NULL > terminated and one of them is a constant? Please do.