Re: [dpdk-dev] [PATCH v3 1/3] drivers/bus: move driver assignment to end of probing

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 10/11/18 2:45 PM, Thomas Monjalon wrote:
> 11/10/2018 12:53, Andrew Rybchenko:
>> On 10/8/18 1:09 AM, Thomas Monjalon wrote:
>>> The PCI mapping requires to know the PCI driver to use,
>>> even before the probing is done. That's why the PCI driver is
>>> referenced early inside the PCI device structure. See
>>> 1d20a073fa5e ("bus/pci: reference driver structure before mapping")
>>>
>>> However the rte_driver does not need to be referenced in rte_device
>>> before the device probing is done.
>>> By moving back this assignment at the end of the device probing,
>>> it becomes possible to make clear the status of a rte_device.
>>>
>>> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
>>> ---
>>> diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
>>> index c7695d108..d63e68045 100644
>>> --- a/drivers/bus/pci/pci_common.c
>>> +++ b/drivers/bus/pci/pci_common.c
>>> @@ -160,14 +160,12 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
>>>    	 * driver flags for adjusting configuration.
>>>    	 */
>>>    	dev->driver = dr;
>>> -	dev->device.driver = &dr->driver;
>> It breaks net/sfc and I guess other drivers which use
>> rte_eth_dma_zone_reserve()
>> from probe. The function makes zone name using dev->device->driver->name.
> Please, can you show code line where we does such access?
>
> I checked such access before and did not find some.
> Anyway, it can be fixed by accessing rte_pci_driver->driver->name.
> Note that rte_pci_driver is referenced in rte_pci_device.

Below in snprintf(), in theory it can be called for vdev as well.

const struct rte_memzone *
rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char 
*ring_name,
                          uint16_t queue_id, size_t size, unsigned align,
                          int socket_id)
{
         char z_name[RTE_MEMZONE_NAMESIZE];
         const struct rte_memzone *mz;

         snprintf(z_name, sizeof(z_name), "%s_%s_%d_%d",
                  dev->device->driver->name, ring_name,
                  dev->data->port_id, queue_id);

         mz = rte_memzone_lookup(z_name);
         if (mz)
                 return mz;

         return rte_memzone_reserve_aligned(z_name, size, socket_id,
                         RTE_MEMZONE_IOVA_CONTIG, align);
}