From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751452AbbJPVQd (ORCPT ); Fri, 16 Oct 2015 17:16:33 -0400 Received: from mail.kernel.org ([198.145.29.136]:35623 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbbJPVQc (ORCPT ); Fri, 16 Oct 2015 17:16:32 -0400 Subject: [PATCH] PCI: Remove unnecessary re-read of SR-IOV offset/stride registers To: linux-pci@vger.kernel.org From: Bjorn Helgaas Cc: Ben Shelton , linux-kernel@vger.kernel.org, Alexander Duyck Date: Fri, 16 Oct 2015 16:16:28 -0500 Message-ID: <20151016211628.31492.86258.stgit@bhelgaas-glaptop2.roam.corp.google.com> User-Agent: StGit/0.16 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 Previously, we read PCI_SRIOV_VF_OFFSET and PCI_SRIOV_VF_STRIDE from the SR-IOV capability in pci_iov_set_numvfs() after changing PCI_SRIOV_NUM_VF, and we read them again in sriov_enable(). But sriov_init() always calls pci_iov_set_numvfs() before a successful return, and it caches the offset and stride values, so there's no need to read the capability again in sriov_enable(). Remove the PCI_SRIOV_VF_OFFSET and PCI_SRIOV_VF_STRIDE config reads from sriov_enable() and use the cached values from the pci_sriov structure. Signed-off-by: Bjorn Helgaas --- drivers/pci/iov.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 0202ab0..9b52ad4 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -230,7 +230,7 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) int rc; int i, j; int nres; - u16 offset, stride, initial; + u16 initial; struct resource *res; struct pci_dev *pdev; struct pci_sriov *iov = dev->sriov; @@ -253,9 +253,7 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial))) return -EINVAL; - pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &offset); - pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &stride); - if (!offset || (nr_virtfn > 1 && !stride)) + if (!iov->offset || (nr_virtfn > 1 && !iov->stride)) return -EIO; nres = 0; @@ -270,9 +268,6 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) return -ENOMEM; } - iov->offset = offset; - iov->stride = stride; - bus = pci_iov_virtfn_bus(dev, nr_virtfn - 1); if (bus > dev->bus->busn_res.end) { dev_err(&dev->dev, "can't enable %d VFs (bus %02x out of range of %pR)\n",