Re: [dpdk-dev] [PATCH v2] net/tap: fix dev name look-up

[Pascal Mazon <pascal.mazon@6wind.com>]

On Mon, 6 Mar 2017 14:27:18 +0000
Ferruh Yigit <ferruh.yigit@intel.com> wrote:

> On 3/6/2017 1:51 PM, Pascal Mazon wrote:
> > Store the device name in dev->data->name, to have symmetrical
> > behavior between rte_pmd_tap_probe(name) and
> > rte_pmd_tap_remove(name).
> > 
> > The netdevice name (linux interface name) is stored in the name
> > field of struct pmd_internals.
> 
> +1 for this.
> 
> > 
> > There's no need to allocate an rte_eth_dev_data, as it is done in
> > rte_eth_dev_allocate()/rte_eth_dev_data_alloc().
> 
> Allocating rte_eth_dev_data, although rte_eth_dev_allocate() does
> already, common practice for virtual devices, for a reason.
> 
> rte_eth_dev_allocate() allocates device data from a shared memory, so
> that multiple DPDK processes can access same device data, this may
> make sense for physical devices, since there is a single physical
> resource.
> 
> But for virtual devices, each DPDK process may want to have
> independent instance of the virtual device, that is why PMD itself
> allocates data and overwrites with existing dev->data.
> 
> Also this may lead unexpected results for some multi process use
> cases, like secondary process virtual device corrupt primary process
> physical device data.
> 
> I believe it is good to keep this as it is.
> 

I see your point.

I'll send a v3 with just the correct "name" used for allocation.
And I'll move the snprintf(data->name) closer, to insist it must use the
same name as in allocation.

Regards,
Pascal

> > 
> > Signed-off-by: Pascal Mazon <pascal.mazon@6wind.com>
> <...>