From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:41147 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751047Ab2KAVMq (ORCPT ); Thu, 1 Nov 2012 17:12:46 -0400 Message-ID: <5092E5C7.7030601@redhat.com> Date: Thu, 01 Nov 2012 17:12:39 -0400 From: Don Dutile MIME-Version: 1.0 To: Ben Hutchings CC: linux-pci@vger.kernel.org, bhelgaas@google.com, yuvalmin@broadcom.com, gregory.v.rose@intel.com, yinghai@kernel.org, davem@davemloft.net Subject: Re: [PATCH 4/4] PCI,sriov: provide method to reduce the number of total VFs supported References: <1351718353-6124-1-git-send-email-ddutile@redhat.com> <1351718353-6124-5-git-send-email-ddutile@redhat.com> <1351727591.2706.52.camel@bwh-desktop.uk.solarflarecom.com> In-Reply-To: <1351727591.2706.52.camel@bwh-desktop.uk.solarflarecom.com> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 10/31/2012 07:53 PM, Ben Hutchings wrote: > On Wed, 2012-10-31 at 17:19 -0400, Donald Dutile wrote: >> Some implementations of SRIOV provide a capability structure >> value of TotalVFs that is greater than what the software can support. >> Provide a method to reduce the capability structure reported value >> to the value the driver can support. >> This ensures sysfs reports the current capability of the system, >> hardware and software. >> Example for its use: igb& ixgbe -- report 8& 64 as TotalVFs, >> but drivers only support 7& 63 maximum. >> >> Signed-off-by: Donald Dutile >> --- >> drivers/pci/iov.c | 27 ++++++++++++++++++++++++++- >> drivers/pci/pci-sysfs.c | 10 ++++++++-- >> drivers/pci/pci.h | 1 + >> include/linux/pci.h | 5 +++++ >> 4 files changed, 40 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c >> index aeccc91..98c3d37 100644 >> --- a/drivers/pci/iov.c >> +++ b/drivers/pci/iov.c >> @@ -682,7 +682,6 @@ int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn) >> >> if (!dev->is_physfn) >> return -ENODEV; >> - >> return sriov_enable(dev, nr_virtfn); >> } >> EXPORT_SYMBOL_GPL(pci_enable_sriov); > > This hunk doesn't belong in this patch. > gone in next rev. >> @@ -735,3 +734,29 @@ int pci_num_vf(struct pci_dev *dev) >> return dev->sriov->nr_virtfn; >> } >> EXPORT_SYMBOL_GPL(pci_num_vf); >> + >> +/** >> + * pci_sriov_set_totalvfs -- reduce the TotalVFs available >> + * @dev: the PCI PF device >> + * numvfs: number that should be used for TotalVFs supported >> + * >> + * Should be called from PF driver's probe routine with >> + * device's mutex held. >> + * >> + * Returns 0 if PF is an SRIOV-capable device and >> + * value of numvfs valid, otherwise -EINVAL > > This says the only possible error is -EINVAL, but it can also return > -EIO! And the already-enabled case might be one that some drivers will > need to handle specially. > >> + */ >> +int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs) >> +{ >> + if (!dev || !dev->is_physfn || (numvfs> dev->sriov->total)) >> + return -EINVAL; >> + >> + /* Shouldn't change if VFs already enabled */ >> + if (dev->sriov->ctrl& PCI_SRIOV_CTRL_VFE) >> + return -EIO; > [...] > > EBUSY seems a bit more appropriate. > > Ben. > ok. changed to -EBUSY & comment on return values. After looking at this area more, I created a pci_sriov_get_totalvfs() as well, and now use that in the pci-sysfs.c file as well.... much cleaner; symmetric to set. Makes backporting to those crazy enterprise releases w/kabi rules easier too! ;-)