Re: [PATCH 5/5] ixgbe: add driver set_max_vfs support

Don Dutile
2012-10-03T19:02:40Z

On 10/03/2012 02:47 PM, Alexander Duyck wrote:
> On 10/03/2012 10:51 AM, Yinghai Lu wrote:
>> Need ixgbe guys to close the loop to use set_max_vfs instead
>> kernel parameters.
>>
>> Signed-off-by: Yinghai Lu<yinghai@kernel.org>
>> Cc: Jeff Kirsher<jeffrey.t.kirsher@intel.com>
>> Cc: Jesse Brandeburg<jesse.brandeburg@intel.com>
>> Cc: Greg Rose<gregory.v.rose@intel.com>
>> Cc: "David S. Miller"<davem@davemloft.net>
>> Cc: John Fastabend<john.r.fastabend@intel.com>
>> Cc: e1000-devel@lists.sourceforge.net
>> Cc: netdev@vger.kernel.org
>> ---
>> drivers/net/ethernet/intel/ixgbe/ixgbe.h | 2 +
>> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 44 +++++++++++++++++++-----
>> 2 files changed, 37 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> index b9623e9..d39d975 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> @@ -558,6 +558,8 @@ struct ixgbe_adapter {
>> u32 interrupt_event;
>> u32 led_reg;
>>
>> + struct ixgbe_info *ixgbe_info;
>> +
>> #ifdef CONFIG_IXGBE_PTP
>> struct ptp_clock *ptp_clock;
>> struct ptp_clock_info ptp_caps;
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> index ee61819..1c097c7 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> @@ -129,13 +129,6 @@ static struct notifier_block dca_notifier = {
>> };
>> #endif
>>
>> -#ifdef CONFIG_PCI_IOV
>> -static unsigned int max_vfs;
>> -module_param(max_vfs, uint, 0);
>> -MODULE_PARM_DESC(max_vfs,
>> - "Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63");
>> -#endif /* CONFIG_PCI_IOV */
>> -
>> static unsigned int allow_unsupported_sfp;
>> module_param(allow_unsupported_sfp, uint, 0);
>> MODULE_PARM_DESC(allow_unsupported_sfp,
>> @@ -4496,7 +4489,7 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
>> #ifdef CONFIG_PCI_IOV
>> /* assign number of SR-IOV VFs */
>> if (hw->mac.type != ixgbe_mac_82598EB)
>> - adapter->num_vfs = (max_vfs> 63) ? 0 : max_vfs;
>> + adapter->num_vfs = min_t(int, pdev->max_vfs, 63);
>>
>> #endif
>> /* enable itr by default in dynamic mode */
>> @@ -7220,8 +7213,9 @@ static int __devinit ixgbe_probe(struct pci_dev *pdev,
>>
>> #ifdef CONFIG_PCI_IOV
>> ixgbe_enable_sriov(adapter, ii);
>> -
>> #endif
>> + adapter->ixgbe_info = ii;
>> +
>> netdev->features = NETIF_F_SG |
>> NETIF_F_IP_CSUM |
>> NETIF_F_IPV6_CSUM |
>> @@ -7683,11 +7677,43 @@ static const struct pci_error_handlers ixgbe_err_handler = {
>> .resume = ixgbe_io_resume,
>> };
>>
>> +static void ixgbe_set_max_vfs(struct pci_dev *pdev)
>> +{
>> +#ifdef CONFIG_PCI_IOV
>> + struct ixgbe_adapter *adapter = pci_get_drvdata(pdev);
>> + struct ixgbe_hw *hw =&adapter->hw;
>> + int num_vfs = 0;
>> +
>> + /* assign number of SR-IOV VFs */
>> + if (hw->mac.type != ixgbe_mac_82598EB)
>> + num_vfs = min_t(int, pdev->max_vfs, 63);
>> +
>> + /* no change */
>> + if (adapter->num_vfs == num_vfs)
>> + return;
>> +
>> + if (!num_vfs) {
>> + /* disable sriov */
>> + ixgbe_disable_sriov(adapter);
>> + adapter->num_vfs = 0;
>> + } else if (!adapter->num_vfs&& num_vfs) {
>> + /* enable sriov */
>> + adapter->num_vfs = num_vfs;
>> + ixgbe_enable_sriov(adapter, adapter->ixgbe_info);
>> + } else {
>> + /* increase or decrease */
>> + }
>> +
>> + pdev->max_vfs = adapter->num_vfs;
>> +#endif
>> +}
>> +
>> static struct pci_driver ixgbe_driver = {
>> .name = ixgbe_driver_name,
>> .id_table = ixgbe_pci_tbl,
>> .probe = ixgbe_probe,
>> .remove = __devexit_p(ixgbe_remove),
>> + .set_max_vfs = ixgbe_set_max_vfs,
>> #ifdef CONFIG_PM
>> .suspend = ixgbe_suspend,
>> .resume = ixgbe_resume,
>
> The ixgbe_set_max_vfs function has several issues. The two big ones are
> that this function assumes it can just enable/disable SR-IOV without any
> other changes being necessary which is not the case. I would recommend
> looking at ixgbe_setup_tc for how to do this properly. Secondly is the
> fact that this code will change the PF network device and as such
> sections of the code should be called with the RTNL lock held. In
> addition I believe you have to disable SR-IOV before enabling it again
> with a different number of VFs.
>
> Below is a link to one of the early patches for igb when we were first
> introducing SR-IOV, and the in-driver sysfs value had been rejected. I
> figure it might be useful as it was also using sysfs to enable/disable
> VFs. It however doesn't have the correct locking on changing the queues
> and as such will likely throw an error if you were to implement it the
> same way now:
> http://lists.openwall.net/netdev/2009/04/08/34
>
> Thanks,
>
> Alex

Alex,
Thanks for patch set pointer.
When I started to work on the ixgbe example use based on the RFC set I posted,
I ran into the problem you outlined -- the PF uses/consumes all the queues &
MSI intrs when sriov not enabled at driver load time, which required
more network shutdown logic that I'm not familiar with... So, I was going
to defer to Greg to work that magic. :)
Greg: assume the 2 callback function interface in the RFC patch set I sent,
(primarily, just the include/linux/pci.h changes), and you can make the
necessary drivers mods from there. In the meantime, I'll make the changes
to my original/v1 RFC to reflect the changes that GKH & Yinghai recommended/implemented
for sysfs attribute creation & removal in a v2 posting.
The end result is that the current module parameter setting for max_vfs should
continue to work, and the sysfs interface will work when those pieces are provided.

-Don