From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751582AbeECUAs (ORCPT ); Thu, 3 May 2018 16:00:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:34456 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751525AbeECUAp (ORCPT ); Thu, 3 May 2018 16:00:45 -0400 Subject: [PATCH v6 5/5] PCI: Remove unused pcie_get_minimum_link() From: Bjorn Helgaas To: Jeff Kirsher , Ganesh Goudar , Michael Chan , Ariel Elior Cc: linux-pci@vger.kernel.org, everest-linux-l2@cavium.com, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Tal Gilboa , Tariq Toukan , Jacob Keller , Jakub Kicinski Date: Thu, 03 May 2018 15:00:43 -0500 Message-ID: <152537764322.62474.552711932384023140.stgit@bhelgaas-glaptop.roam.corp.google.com> In-Reply-To: <152537719056.62474.2571390812509425478.stgit@bhelgaas-glaptop.roam.corp.google.com> References: <152537719056.62474.2571390812509425478.stgit@bhelgaas-glaptop.roam.corp.google.com> User-Agent: StGit/0.18 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bjorn Helgaas In some cases pcie_get_minimum_link() returned misleading information because it found the slowest link and the narrowest link without considering the total bandwidth of the link. For example, consider a path with these two links: - 16.0 GT/s x1 link (16.0 * 10^9 * 128 / 130) * 1 / 8 = 1969 MB/s - 2.5 GT/s x16 link ( 2.5 * 10^9 * 8 / 10) * 16 / 8 = 4000 MB/s The available bandwidth of the path is limited by the 16 GT/s link to about 1969 MB/s, but pcie_get_minimum_link() returned 2.5 GT/s x1, which corresponds to only 250 MB/s. Callers should use pcie_print_link_status() instead, or pcie_bandwidth_available() if they need more detailed information. Remove pcie_get_minimum_link() since there are no callers left. Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 43 ------------------------------------------- include/linux/pci.h | 2 -- 2 files changed, 45 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e597655a5643..4bafa817c40a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5069,49 +5069,6 @@ int pcie_set_mps(struct pci_dev *dev, int mps) } EXPORT_SYMBOL(pcie_set_mps); -/** - * pcie_get_minimum_link - determine minimum link settings of a PCI device - * @dev: PCI device to query - * @speed: storage for minimum speed - * @width: storage for minimum width - * - * This function will walk up the PCI device chain and determine the minimum - * link width and speed of the device. - */ -int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, - enum pcie_link_width *width) -{ - int ret; - - *speed = PCI_SPEED_UNKNOWN; - *width = PCIE_LNK_WIDTH_UNKNOWN; - - while (dev) { - u16 lnksta; - enum pci_bus_speed next_speed; - enum pcie_link_width next_width; - - ret = pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); - if (ret) - return ret; - - next_speed = pcie_link_speed[lnksta & PCI_EXP_LNKSTA_CLS]; - next_width = (lnksta & PCI_EXP_LNKSTA_NLW) >> - PCI_EXP_LNKSTA_NLW_SHIFT; - - if (next_speed < *speed) - *speed = next_speed; - - if (next_width < *width) - *width = next_width; - - dev = dev->bus->self; - } - - return 0; -} -EXPORT_SYMBOL(pcie_get_minimum_link); - /** * pcie_bandwidth_available - determine minimum link settings of a PCIe * device and its bandwidth limitation diff --git a/include/linux/pci.h b/include/linux/pci.h index 73178a2fcee0..230615620a4a 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1079,8 +1079,6 @@ int pcie_get_readrq(struct pci_dev *dev); int pcie_set_readrq(struct pci_dev *dev, int rq); int pcie_get_mps(struct pci_dev *dev); int pcie_set_mps(struct pci_dev *dev, int mps); -int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, - enum pcie_link_width *width); u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, enum pci_bus_speed *speed, enum pcie_link_width *width);