Re: [PATCH 0/4] Provide netdev naming-policy via sysfs

[Tom Gundersen]

On Thu, Feb 27, 2014 at 3:47 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
> This series implements a new sysfs attribute for netdevs called
> "name_assign_type". It provides an integer that describes where an interface
> name comes from. See Patch #1 for a description of this attribute. It is
> modelled after the existing "addr_assign_type" attribute.
>
> The main use-case is to allow udev to skip applying reliable ifnames to virtual
> devices. For instance, if wifi-P2P devices are created, wpas already provides a
> suitable naming-policy and udev shouldn't touch these devices. Same is true for
> other virtual devices.
> The idea is that if a device-name was provided by user-space, we should always
> prefer fixing this naming-policy instead of making udev rename the device. For
> kernel provided names that's hardly possible, though. Providing the
> naming-policy source via sysfs is thus a simple way to see whether renames are
> needed.
>
> Additionally, this field allows to detect whether a netdev has been manually
> renamed, which is quite useful for debugging and during crash-recovery.

Moreover, it would be useful for udev to reliably know if some other
userspace process already renamed a device, so we know not to touch
it. This can easily happen for instance if some renaming happens in
the initrd or from script called from udev rules.

Acked-by: Tom Gundersen <teg@xxxxxxx>

> David Herrmann (4):
>   net: add name_assign_type netdev attribute
>   mac80211: set NET_NAME_USER for user-space created ifs
>   ath6kl: set NET_NAME_USER for P2P ifs
>   brcmfmac: set NET_NAME_USER for P2P ifs
>
>  drivers/net/wireless/ath/ath6kl/cfg80211.c    | 5 ++++-
>  drivers/net/wireless/ath/ath6kl/cfg80211.h    | 1 +
>  drivers/net/wireless/ath/ath6kl/core.c        | 4 ++--
>  drivers/net/wireless/brcm80211/brcmfmac/p2p.c | 1 +
>  include/linux/netdevice.h                     | 6 ++++++
>  net/core/dev.c                                | 7 +++++++
>  net/core/net-sysfs.c                          | 2 ++
>  net/core/rtnetlink.c                          | 2 ++
>  net/mac80211/iface.c                          | 1 +
>  9 files changed, 26 insertions(+), 3 deletions(-)
>
> --
> 1.9.0
>
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