When the name_assign_type attribute was introduced (commit
685343fc3ba6, "net: add name_assign_type netdev attribute"), the
loopback device was explicitly mentioned as one which would make use
of NET_NAME_PREDICTABLE:
The name_assign_type attribute gives hints where the interface name of a
given net-device comes from. These values are currently defined:
...
NET_NAME_PREDICTABLE:
The ifname has been assigned by the kernel in a predictable way
that is guaranteed to avoid reuse and always be the same for a
given device. Examples include statically created devices like
the loopback device [...]
Switch to that so that reading /sys/class/net/lo/name_assign_type
produces something sensible instead of returning -EINVAL.
Signed-off-by: Rasmus Villemoes <[email protected]>
---
This is mostly cosmetic, but ideally I'd like to get to a situation
where I don't need to do
assign_type=$(cat /sys/class/net/$dev/name_assign_type 2> /dev/null || echo 0)
or otherwise special-case [ $dev = "lo" ].
As always, there's a small chance that this could cause a regression,
but it seems extremely unlikely that anybody relies on
/sys/class/net/lo/name_assign_type being unreadable and thus
effectively is known to be NET_NAME_UNKNOWN.
drivers/net/loopback.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 14e8d04cb434..2e9742952c4e 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -211,7 +211,7 @@ static __net_init int loopback_net_init(struct net *net)
int err;
err = -ENOMEM;
- dev = alloc_netdev(0, "lo", NET_NAME_UNKNOWN, loopback_setup);
+ dev = alloc_netdev(0, "lo", NET_NAME_PREDICTABLE, loopback_setup);
if (!dev)
goto out;
--
2.37.2
> -----Original Message-----
> From: Rasmus Villemoes <[email protected]>
> Sent: Wednesday, November 23, 2022 6:18 AM
> To: David S. Miller <[email protected]>; Eric Dumazet
> <[email protected]>; Jakub Kicinski <[email protected]>; Paolo Abeni
> <[email protected]>
> Cc: Rasmus Villemoes <[email protected]>; [email protected];
> [email protected]
> Subject: [PATCH] net: loopback: use NET_NAME_PREDICTABLE for
> name_assign_type
>
> When the name_assign_type attribute was introduced (commit
> 685343fc3ba6, "net: add name_assign_type netdev attribute"), the
> loopback device was explicitly mentioned as one which would make use
> of NET_NAME_PREDICTABLE:
>
> The name_assign_type attribute gives hints where the interface name of a
> given net-device comes from. These values are currently defined:
> ...
> NET_NAME_PREDICTABLE:
> The ifname has been assigned by the kernel in a predictable way
> that is guaranteed to avoid reuse and always be the same for a
> given device. Examples include statically created devices like
> the loopback device [...]
>
Heh, so the doc says loopback is an example of this but we weren't using it for that :D
> Switch to that so that reading /sys/class/net/lo/name_assign_type
> produces something sensible instead of returning -EINVAL.
>
This seems reasonable to me.
> Signed-off-by: Rasmus Villemoes <[email protected]>
> ---
>
> This is mostly cosmetic, but ideally I'd like to get to a situation
> where I don't need to do
>
> assign_type=$(cat /sys/class/net/$dev/name_assign_type 2> /dev/null || echo
> 0)
>
> or otherwise special-case [ $dev = "lo" ].
>
> As always, there's a small chance that this could cause a regression,
> but it seems extremely unlikely that anybody relies on
> /sys/class/net/lo/name_assign_type being unreadable and thus
> effectively is known to be NET_NAME_UNKNOWN.
>
I don't think I would consider this a regression. Previously name_assign_type was returning an error here, now it reports something useful. And we know the name is predictable because
it is the loopback device.
Reviewed-by: Jacob Keller <[email protected]>
> drivers/net/loopback.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
> index 14e8d04cb434..2e9742952c4e 100644
> --- a/drivers/net/loopback.c
> +++ b/drivers/net/loopback.c
> @@ -211,7 +211,7 @@ static __net_init int loopback_net_init(struct net *net)
> int err;
>
> err = -ENOMEM;
> - dev = alloc_netdev(0, "lo", NET_NAME_UNKNOWN, loopback_setup);
> + dev = alloc_netdev(0, "lo", NET_NAME_PREDICTABLE, loopback_setup);
> if (!dev)
> goto out;
>
> --
> 2.37.2
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:
On Wed, 23 Nov 2022 15:18:28 +0100 you wrote:
> When the name_assign_type attribute was introduced (commit
> 685343fc3ba6, "net: add name_assign_type netdev attribute"), the
> loopback device was explicitly mentioned as one which would make use
> of NET_NAME_PREDICTABLE:
>
> The name_assign_type attribute gives hints where the interface name of a
> given net-device comes from. These values are currently defined:
> ...
> NET_NAME_PREDICTABLE:
> The ifname has been assigned by the kernel in a predictable way
> that is guaranteed to avoid reuse and always be the same for a
> given device. Examples include statically created devices like
> the loopback device [...]
>
> [...]
Here is the summary with links:
- net: loopback: use NET_NAME_PREDICTABLE for name_assign_type
https://git.kernel.org/netdev/net/c/31d929de5a11
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html