On Wed, Sep 28, 2016 at 08:07:01AM -0400, David Miller wrote: ... > > > > I think you miss the point what I'm trying to say: currently end-user > > may have reference to this member (for any reason) and his program > > will compile and run. If we change the name the compilation procedure > > fails and this will break API. Yes, referrning @pad is bad idea for > > userspace code, and yes (!) better to simply rename it but lets do > > that later, on top, so that if we break something in userspace > > we could easily revert the oneline change. > > Right, it would be legal for an existing user to have code that > explicitly initializes every member of the structure, including 'pad'. > So we have to keep that member around, at a minimum, for their sake.
+1 > > >> BTW: There is at least one major structure in inet diag has a hole > >> today and doesnt have a padding indicator. > >> > >> > If protocol goes over u8 then complete inet_diag_req_v2 structure will > >> > have to be reworked becaue @sdiag_protocol is u8 as well. IOW, once > >> > someone liftup IPPROTO_MAX > 255, he will notice the problem immediately > >> > because diag for such module simply stop working properly. > > Indeed, we need a 16-bit value here. Yes, and we will need inet_diag_req_v3 for this sake ;) I think we can even introduce it early and convert _v2 to _v3 transparently inside kernel. I could start working on such change if people agreed (but a bit latter, on the next week probably)
