Re: [PATCH net-next v2 3/9] ethtool: add a new command for reading standard stats
From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-04-17 18:13:55
On Sat, 17 Apr 2021 10:57:42 -0700 Jakub Kicinski wrote:
quoted
I tried to understand how you add new groups without user space changes and I think this statement is not entirely accurate. At minimum, user space needs to know the names of these groups, but currently there is no way to query the information, so it's added to ethtool's help message: ethtool [ FLAGS ] -S|--statistics DEVNAME Show adapter statistics [ --groups [eth-phy] [eth-mac] [eth-ctrl] [rmon] ]Um, yes and now. The only places the user space puts those names is the help message and man page. Thru the magic of bitsets it doesn't actually interpret them, so with old user space you can still query a new group, it will just not show up in "ethtool -h". Is that what you're saying?
FWIW ethnl_parse_bit() -> ETHTOOL_A_BITSET_BIT_NAME User space can also use raw flags like --groups 0xf but that's perhaps too spartan for serious use.