Re: [dpdk-dev] [PATCH v2] net/bonding: support bifurcated driver in eal cli using --vdev

[Thomas Monjalon <thomas@monjalon.net>]

Ping - any news?

31/07/2017 16:34, Gaëtan Rivet:
> Hi Gowrishankar, Declan,
> 
> On Mon, Jul 10, 2017 at 12:02:24PM +0530, gowrishankar muthukrishnan wrote:
> > On Friday 07 July 2017 09:08 PM, Declan Doherty wrote:
> > >On 04/07/2017 12:57 PM, Gowrishankar wrote:
> > >>From: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>
> > >>
> > >>At present, creating bonding devices using --vdev is broken for PMD like
> > >>mlx5 as it is neither UIO nor VFIO based and hence PMD driver is unknown
> > >>to find_port_id_by_pci_addr(), as below.
> > >>
> > >>testpmd <EAL args> --vdev 'net_bonding0,mode=1,slave=<PCI>,socket_id=0'
> > >>
> > >>PMD: bond_ethdev_parse_slave_port_kvarg(150) - Invalid slave port value
> > >> (<PCI ID>) specified
> > >>EAL: Failed to parse slave ports for bonded device net_bonding0
> > >>
> > >>This patch fixes parsing PCI ID from bonding device params by verifying
> > >>it in RTE PCI bus, rather than checking dev->kdrv.
> > >>
> > >>Changes:
> > >>  v2 - revisit fix by iterating rte_pci_bus
> > >>
> > >>Signed-off-by: Gowrishankar Muthukrishnan
> > >><gowrishankar.m@linux.vnet.ibm.com>
> > >>---
> > >...
> > >>
> > >
> > >Hey Gowrishankar,
> > >
> > >I was having a look at this patch and there is the following checkpatch
> > >error.
> > >
> > >_coding style issues_
> > >
> > >
> > >WARNING:AVOID_EXTERNS: externs should be avoided in .c files
> > >#48: FILE: drivers/net/bonding/rte_eth_bond_args.c:43:
> > >+extern struct rte_pci_bus rte_pci_bus;
> > >
> > Hi Declan,
> > Thank you for your review.
> > Yes, but I also saw some references like above in older code.
> > 
> > >
> > >Looking at bit closer at the issue I think there is a simpler solution,
> > >the bonding driver really shouldn't be parsing the PCI bus directly, and
> > >since PCI devices use the PCI DBF as their name we can simply replace the
> > >all the scanning code with a simple call to rte_eth_dev_get_port_by_name
> > >API.
> > >
> 
> I agree that it would be better to be able to use the ether API for
> this.
> 
> The issue is that PCI devices are inconsistent regarding their names. The
> possibility is given to the user to employ the simplified BDF format for
> PCI device name, instead of the DomBDF format.
> 
> Unfortunately, the default device name for a PCI device is in the DomBDF
> format. This means that the name won't match if the device was probed by
> using the PCI blacklist mode (the default PCI mode).
> 
> The matching must be refined.
> 
> > 
> > But you are removing an option to mention ports by PCI addresses right  (as
> > I see parse_port_id() completely removed in your patch) ?.
> > IMO, we just need to check if given eth pci id (incase we mention ports ib
> > PCI ID) is one of what EAL scanned in PCI. Also, slaves should not be from
> > any blacklisted PCI ids (as we test with -b or -w).
> > 
> 
> Declan is right about the iteration of PCI devices. The device list for
> the PCI bus is private, the extern declaration to the rte_pci_bus is the
> telltale sign that there is something wrong in the approach here.
> 
> In order to respect the new rte_bus logic, I think what you want to
> achieve can be done by using the rte_bus->find_device with the correct
> device comparison function.
> 
> static int
> pci_addr_cmp(const struct rte_device *dev, const void *_pci_addr)
> {
>     struct rte_pci_device *pdev;
>     char *addr = _pci_addr;
>     struct rte_pci_addr paddr;
>     static struct rte_bus *pci_bus = NULL;
> 
>     if (pci_bus == NULL)
>         pci_bus = rte_bus_find_by_name("pci");
> 
>     if (pci_bus->parse(addr, &paddr) != 0) {
>         /* Invalid PCI addr given as input. */
>         return -1;
>     }
>     pdev = RTE_DEV_TO_PCI(dev);
>     return rte_eal_compare_pci_addr(&pdev->addr, &paddr);
> }
> 
> Then verify that you are able to get a device by using it as follows:
> 
> {
>     struct rte_bus *pci_bus;
>     struct rte_device *dev;
> 
>     pci_bus = rte_bus_find_by_name("pci");
>     if (pci_bus == NULL) {
>         RTE_LOG(ERR, PMD, "Unable to find PCI bus\n");
>         return -1;
>     }
>     dev = pci_bus->find_device(NULL, pci_addr_cmp, devname);
>     if (dev == NULL) {
>         RTE_LOG(ERR, PMD, "Unable to find the device %s to enslave.\n",
>                 devname);
>         return -EINVAL;
>     }
> }
> 
> I hope it's clear enough. You can find examples of use for this API in
> lib/librte_eal/common/eal_common_dev.c
> 
> It's a quick implementation to outline the possible direction, I
> haven't compiled it. It should be refined.
> 
> For example, the PCI address validation should not be happening in the
> comparison function, the pci_bus could be matched once instead of twice,
> etc...
> 
> But the logic should work.
> 
> Best regards,
>