Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754276Ab3GLCbQ (ORCPT ); Thu, 11 Jul 2013 22:31:16 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:36368 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751111Ab3GLCbO (ORCPT ); Thu, 11 Jul 2013 22:31:14 -0400 Message-ID: <51DF6A48.4070506@huawei.com> Date: Fri, 12 Jul 2013 10:30:32 +0800 From: Yijing Wang User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: Bjorn Helgaas CC: Don Dutile , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , Rafael , Hanjun Guo , Jiang Liu Subject: Re: [PATCH -v2 1/3] PCI: introduce PCIe Device Serial Number Capability support References: <1373535825-49972-1-git-send-email-wangyijing@huawei.com> <1373535825-49972-2-git-send-email-wangyijing@huawei.com> <51DE8032.4040808@redhat.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.76.69] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2041 Lines: 76 >> } >>> >>> + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN); >>> + if (!pos) >>> + return 0; >>> + >>> + pci_read_config_dword(dev, pos + 4,&lo); >>> + pci_read_config_dword(dev, pos + 8,&hi); >>> + sn = ((u64)hi<< 32) | lo; >> >> See comment below: >> dev->sn = ((u64)hi<< 32) | lo; >> return; >> >>> + return sn; >>> +} >>> +EXPORT_SYMBOL(pci_device_serial_number); >>> + >>> +/** >>> * pci_configure_ari - enable or disable ARI forwarding >>> * @dev: the PCI device >>> * >>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c >>> index 46ada5c..c4c1a2b 100644 >>> --- a/drivers/pci/probe.c >>> +++ b/drivers/pci/probe.c >>> @@ -1322,6 +1322,8 @@ static void pci_init_capabilities(struct pci_dev >>> *dev) >>> /* Power Management */ >>> pci_pm_init(dev); >>> >>> + dev->sn = pci_device_serial_number(dev); >>> + >> >> Finally, 'the comment below': >> I know you were following Bjorn's suggestion, which I thought >> was an improvement, but why not do above assignment in >> pci_device_serial_number() ? >> See above.... > > pci_device_serial_number() would then have the side-effect of saving > the result somewhere, and callers would have to know where to look. > Personally, I think it's simpler to return the serial number directly > and avoid the side-effect, but maybe this is just bike-shedding. > > As long as we are bike-shedding, I'd just drop "sn" and do: > > return ((u64)hi << 32) | lo; > > And of course, you need spaces before "&hi" and "&lo" in the > pci_read_config_dword() calls. OK, will drop "sn", strangely my original patch has spaces before "&hi" and "&lo", but in reply the spaces disappeared. Thanks! Yijing. > > . > -- Thanks! Yijing -- 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/