[PATCH v4] tap: do not duplicate fd's

[Stephen Hemminger]

On Wed, 24 Apr 2024 17:57:46 +0100
Ferruh Yigit <ferruh.yigit at amd.com> wrote:

> OK to merge file descriptors instead of duplicating them.
> 
> But we have this 4 queue limitation only for multi process case, right?
> If user is planning to use only with primary, this will reduce the
> supported queue number.
> 
> Does it make sense to enforce this limitation for secondary only and
> keep TAP_MAX_QUEUES same?
> So for multi process usecase supported queue number will be 8, for
> primary only use case it will remain 16.
> 
> <...>

Yes, the lower limit only applies to the secondary process.
But any application using secondary processes will have the problem;
i.e it is not that primary gets 16 and the secondary only sees 8.

Lets keep MAX_QUEUES at 16 for now, and let users see the warning.
For 24.11 up the max passed fd's to what Linux allows.