From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 6 Apr 2016 10:48:40 +1000 From: Gavin Shan To: Yongji Xie Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, bhelgaas@google.com, corbet@lwn.net, aik@ozlabs.ru, alex.williamson@redhat.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, gwshan@linux.vnet.ibm.com Subject: Re: [RFC v5 1/7] PCI: Ignore resource_alignment if PCI_PROBE_ONLY was set Message-ID: <20160406004840.GA6187@gwshan> Reply-To: Gavin Shan References: <1459863813-2830-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1459863813-2830-2-git-send-email-xyjxie@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1459863813-2830-2-git-send-email-xyjxie@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Tue, Apr 05, 2016 at 09:43:29PM +0800, Yongji Xie wrote: >The resource_alignment will releases memory >resources allocated by firmware so that kernel >can reassign new resources later on. But this >will cause the problem that no resources can be >allocated by kernel if PCI_PROBE_ONLY was set, >e.g. on pSeries platform because PCI_PROBE_ONLY >force kernel to use firmware setup and not to >reassign any resources. > >To solve this problem, this patch ignores >resource_alignment if PCI_PROBE_ONLY was set. > >Signed-off-by: Yongji Xie >--- > drivers/pci/pci.c | 6 ++++++ > 1 file changed, 6 insertions(+) > >diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >index 602eb42..1db9267 100644 >--- a/drivers/pci/pci.c >+++ b/drivers/pci/pci.c >@@ -4607,6 +4607,12 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) > spin_lock(&resource_alignment_lock); > p = resource_alignment_param; > while (*p) { >+ if (pci_has_flag(PCI_PROBE_ONLY)) { >+ printk(KERN_ERR "PCI: Ignore resource_alignment parameter: %s with" >+ " PCI_PROBE_ONLY set\n", p); >+ *p = 0; >+ break; It seems no "*p = 0" isn't required if I don't miss anything. If the check on flag PCI_PROBE_ONLY is moved before the spin_lock(), it would save a bit CPU cycles at least. Also, the logic looks more clear. >+ } > count = 0; > if (sscanf(p, "%d%n", &align_order, &count) == 1 && > p[count] == '@') { Thanks, Gavin >-- >1.7.9.5 >