Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932461Ab3GLBj0 (ORCPT ); Thu, 11 Jul 2013 21:39:26 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:29376 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932194Ab3GLBjY (ORCPT ); Thu, 11 Jul 2013 21:39:24 -0400 Message-ID: <51DF5DFC.3090107@huawei.com> Date: Fri, 12 Jul 2013 09:38:04 +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: Don Dutile CC: Bjorn Helgaas , , , Rafael , Hanjun Guo , 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: <51DE8032.4040808@redhat.com> 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: 2335 Lines: 77 Hi Don, Thanks for your review and comments very much! >> + 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() ? I don't do assignment in pci_device_serial_number() because pci_device_serial_number() is an EXPORT_SYMBOL, and will be used to get dsn for non-scaned device, for example: 1. we have pcie device in slot before suspend. 2. we removed the device during suspend. 3. we reinserted a new device during suspend. 4. we should check the device change during resume, so we try to use pcie device serial number to identify changes. But the pci_dev structure maybe the old stale data. So I prefer to get dsn by return. what about this: static void pci_init_capabilities(struct pci_dev *dev) ........ pci_dsn_init(dev); .......... void pci_dsn_init(dev) { dev->sn = pci_device_serial_number(dev); } > See above.... > - Don > >> /* Vital Product Data */ >> pci_vpd_pci22_init(dev); >> >> diff --git a/include/linux/pci.h b/include/linux/pci.h >> index 0fd1f15..10d190b 100644 >> --- a/include/linux/pci.h >> +++ b/include/linux/pci.h >> @@ -342,6 +342,7 @@ struct pci_dev { >> struct list_head msi_list; >> struct kset *msi_kset; >> #endif >> + u64 sn; /* device serieal number, 0 if not support */ >> struct pci_vpd *vpd; >> #ifdef CONFIG_PCI_ATS >> union { >> @@ -995,6 +996,8 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf); >> ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf); >> int pci_vpd_truncate(struct pci_dev *dev, size_t size); >> >> +u64 pci_device_serial_number(struct pci_dev *dev); >> + >> /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */ >> resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx); >> void pci_bus_assign_resources(const struct pci_bus *bus); > > > . > -- 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/