On Tue, 21 Oct 2025 12:59:34 +0900 Kohei Enju wrote:

For example, consider a scenario where the queue count is 8 with user
configuration containing values from 0 to 7. When queue count changes
from 8 to 4 and we skip the reinitialization in this scenario, entries
pointing to queues 4-7 become invalid. The same issue applies when the
RETA table size changes.

Core should reject this. See ethtool_check_max_channel()

Furthermore, IIUC, adding netif_is_rxfh_configured() to the current
condition wouldn't provide additional benefit. When parameters remain
unchanged, regardless of netif_is_rxfh_configured(), we already preserve
the RETA entries which might be user-configured or default values, 

User may decide to "isolate" (take out of RSS) a lower queue,
to configure it for AF_XDP or other form of zero-copy. Install
explicit rules to direct traffic to that queue. If you reset
the RSS table random traffic will get stranded in the ZC queue
(== dropped).