Merge branch 'netdev-name-in-use'

Merge branch 'netdev-name-in-use'

Antoine Tenart says:

====================
net: introduce a function to check if a netdev name is in use

This was initially part of an RFC series[1] but has value on its own;
hence the standalone report. (It will also help in not having a series
too large).

From patch 1:

"""
__dev_get_by_name is currently used to either retrieve a net device
reference using its name or to check if a name is already used by a
registered net device (per ns). In the later case there is no need to
return a reference to a net device.

Introduce a new helper, netdev_name_in_use, to check if a name is
currently used by a registered net device without leaking a reference
the corresponding net device. This helper uses netdev_name_node_lookup
instead of __dev_get_by_name as we don't need the extra logic retrieving
a reference to the corresponding net device.
"""

Two uses[2] of __dev_get_by_name weren't converted to this new function,
as they are really looking for a net device, not only checking if a net
device name is in use. While checking one or the other currently has
the same result, that might change if the initial RFC series moves
forward. I'll convert them later depending on the outcome of the initial
series.

Thanks,
Antoine

[1] https://lore.kernel.org/all/20210928125500.167943-1-atenart@kernel.org/
[2] drivers/net/Space.c:130 & drivers/nvme/host/tcp.c:2550
====================

Signed-off-by: David S. Miller <davem@davemloft.net>