On 07/12/2020 20:10, Jakub Kicinski wrote: > On Mon, 7 Dec 2020 11:35:53 -0800 Brian Norris wrote: >> Is there some reference for this rule (e.g., dictate from on high; or >> some explanation of reasons)? Or limitations on it? > > TBH its one of those "widely accepted truth" in networking which was > probably discussed before I started compiling kernels so I don't know > the full background. My understanding is that it's because users can have them in their modprobe.conf, which causes breakage if an update removes the param. I think the module insert fails if there are unrecognised parameters there. >> this sounds like one could never drop a module parameter, or remove >> obsolete features. Not far from the truth. If you stop the network from coming up on boot you can really ruin a sysadmin's day :-/ But usually you can remove the feature, and leave the modparam not connected to anything, except maybe a deprecation warning printk if it's set to something other than the default. -ed
