Re: [Patch v4 01/17] net/mana: add basic driver, build environment and doc

[Thomas Monjalon <thomas@monjalon.net>]

22/08/2022 20:27, Long Li:
> > Subject: Re: [Patch v4 01/17] net/mana: add basic driver, build environment
> > and doc
> > 
> > On 8/22/2022 4:03 PM, Ferruh Yigit wrote:
> > >> +                             struct rte_pci_device *pci_dev,
> > >> +                             struct rte_ether_addr *mac_addr) {
> > >> +       struct ibv_device **ibv_list;
> > >> +       int ibv_idx;
> > >> +       struct ibv_context *ctx;
> > >> +       struct ibv_device_attr_ex dev_attr;
> > >> +       int num_devices;
> > >> +       int ret = 0;
> > >> +       uint8_t port;
> > >> +       struct mana_priv *priv = NULL;
> > >> +       struct rte_eth_dev *eth_dev = NULL;
> > >> +       bool found_port;
> > >> +
> > >> +       ibv_list = ibv_get_device_list(&num_devices);
> > >> +       for (ibv_idx = 0; ibv_idx < num_devices; ibv_idx++) {
> > >> +               struct ibv_device *ibdev = ibv_list[ibv_idx];
> > >> +               struct rte_pci_addr pci_addr;
> > >> +
> > >> +               DRV_LOG(INFO, "Probe device name %s dev_name %s
> > >> ibdev_path %s",
> > >> +                       ibdev->name, ibdev->dev_name,
> > >> +ibdev->ibdev_path);
> > >> +
> > >> +               if (mana_ibv_device_to_pci_addr(ibdev, &pci_addr))
> > >> +                       continue;
> > >> +
> > >> +               /* Ignore if this IB device is not this PCI device */
> > >> +               if (pci_dev->addr.domain != pci_addr.domain ||
> > >> +                   pci_dev->addr.bus != pci_addr.bus ||
> > >> +                   pci_dev->addr.devid != pci_addr.devid ||
> > >> +                   pci_dev->addr.function != pci_addr.function)
> > >> +                       continue;
> > >> +
> > >
> > > As far as I understand, intention of this loop is to find 'ibdev'
> > > matching this device, code gooes through all "ibv device list" for
> > > this, I wonder if there is a easy way for doing this, like a sysfs
> > > entry to help getting this information?
> > > And how mlx4/5 does this?
> > 
> > Since there are multiple RDMA devices now, does it make sense to have
> > RDMA bus driver, which can hide some PCIe details under bus, and driver can
> > get PCI and ibdev information during probe?
> 
> Mellanox drivers use a similar way to go through the list of IB devices.
> 
> Matan, Viacheslav, what are your thoughts on implementing a bus for RDMA devices?

These are PCI devices first.
Is it a good idea to have a bus driver on top of another one?
What would be the responsibility of such a bus driver?