Re: [dpdk-dev] [PATCH] net/thunderx: manage PCI device mapping for SQS VFs

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Tue, 6 Jun 2017 14:36:09 +0100
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, dev@dpdk.org
> CC: Angela Czubak <aczubak@caviumnetworks.com>, Thomas Monjalon
>  <thomas@monjalon.net>
> Subject: Re: [dpdk-dev] [PATCH] net/thunderx: manage PCI device mapping for
>  SQS VFs
> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
>  Thunderbird/52.1.1
> 
> On 6/1/2017 2:05 PM, Jerin Jacob wrote:
> > Since the commit e84ad157b7bc ("pci: unmap resources if probe fails"),
> > EAL unmaps the PCI device if ethdev probe returns positive or
> > negative value.
> > 
> > nicvf thunderx PMD needs special treatment for Secondary queue set(SQS)
> > PCIe VF devices, where, it expects to not unmap or free the memory
> > without registering the ethdev subsystem.
> > 
> > To keep the same behavior, moved the PCI map function inside
> > the driver without using the EAL services.
> 
> What do you think adding a flag something like
> RTE_PCI_DRV_FIXED_MAPPING? Does mapping but not unmap on error.
> This would be more generic solution.
> 
> I am concerned about calling eal level API from PMD.

Understood.

Another option is to unmap only on ERROR(ie, when probe return <0 value)

	ret = dr->probe(dr, dev);
        if (ret) { // change to if (ret < 0)
                dev->driver = NULL;
                if (dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING)
                        rte_pci_unmap_device(dev);
        }

I am fine with either way. Let me know, what you prefer. I will
change accordingly.

>
> > 
> > Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> > Signed-off-by: Angela Czubak <aczubak@caviumnetworks.com>
> > ---
> >  drivers/net/thunderx/nicvf_ethdev.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/thunderx/nicvf_ethdev.c b/drivers/net/thunderx/nicvf_ethdev.c
> > index 796701b0f..6ec2f9266 100644
> > --- a/drivers/net/thunderx/nicvf_ethdev.c
> > +++ b/drivers/net/thunderx/nicvf_ethdev.c
> > @@ -2025,6 +2025,13 @@ nicvf_eth_dev_init(struct rte_eth_dev *eth_dev)
> >  	}
> >  
> >  	pci_dev = RTE_ETH_DEV_TO_PCI(eth_dev);
> > +
> > +	ret = rte_pci_map_device(pci_dev);
> > +	if (ret) {
> > +		PMD_INIT_LOG(ERR, "Failed to map pci device");
> > +		goto fail;
> > +	}
> > +
> >  	rte_eth_copy_pci_info(eth_dev, pci_dev);
> >  
> >  	nic->device_id = pci_dev->id.device_id;
> > @@ -2171,7 +2178,7 @@ static int nicvf_eth_pci_remove(struct rte_pci_device *pci_dev)
> >  
> >  static struct rte_pci_driver rte_nicvf_pmd = {
> >  	.id_table = pci_id_nicvf_map,
> > -	.drv_flags = RTE_PCI_DRV_NEED_MAPPING | RTE_PCI_DRV_INTR_LSC,
> > +	.drv_flags = RTE_PCI_DRV_INTR_LSC,
> >  	.probe = nicvf_eth_pci_probe,
> >  	.remove = nicvf_eth_pci_remove,
> >  };
> > 
>