On Fri, Mar 02, 2018 at 09:21:56AM -0500, Alexander Aring wrote: > Hi, > > On Fri, Mar 2, 2018 at 3:37 AM, Jiri Pirko <j...@resnulli.us> wrote: > > Fri, Mar 02, 2018 at 04:48:40AM CET, kubak...@wp.pl wrote: > >>On Thu, 1 Mar 2018 22:38:50 -0500, Alexander Aring wrote: > >>> I guess to make extack working, you need to return an errno if failed. > >> > >>AFAIK extack is printed as a warning if operation did not fail. > > > > Yes, I checked this and it is printed as warning. > > ouch, so far I know extack it allows only one messages delivered back > to the user space. > > If we introduce a warning in the successful path here, it could be > that in the callpath (after "successful" part of this callback), that > somebody else want to add a warning and overwrites actually your > warning (even, he is not aware that this warning was set - okay I > suppose you can do another check on NULL and set a warning, that > somebody overwrites a warning :-D). > > If extack messages get's append and is some kind of for_each_nested > string in netlink -> we have no problem, but I guess this not how it's > working. :-/
IOW I guess what we are looking for here is a way to use extack to track more than an error/warning message, but to be a bit more complete error reporting tool. The case here is pretty much like the case with tc flower offloading, to issue a message when it couldn't offload while it wasn't fatal for the rule (in case SKIP_SW wasn't specified). The reason for why the offloading couldn't happen could have been a temporary one and such log of a warning is important for troubleshooting. Marcelo
