[net] Revert "net: core: maybe return -EEXIST in __dev_alloc_name"

[Johannes Berg]

Hi,

> This revert seems to have broken networking on one of my powerpc
> machines, according to git bisect.

Fun!

TBH, I only looked at the immediate problem we ran into, and reverted
what was causing it. I don't think we saw the follow-up problem you're
seeing.

> The symptom is DHCP fails and I don't get a link, I didn't dig any
> further than that. I can if it's helpful.
> 
> I think the problem is that 87c320e51519 ("net: core: dev_get_valid_name
> is now the same as dev_alloc_name_ns") only makes sense while
> d6f295e9def0 remains in the tree.
> 
> ie. before the entire series, dev_get_valid_name() would return EEXIST,
> and that was retained when 87c320e51519 was merged, but now that
> d6f295e9def0 has been reverted dev_get_valid_name() is returning ENFILE.
> 
> I can get the network up again if I also revert 87c320e51519 ("net:
> core: dev_get_valid_name is now the same as dev_alloc_name_ns"), or with
> the gross patch below.

Makes sense. I guess that should be reverted too then, or even your
"gross" patch applied.

johannes