Sun, Mar 04, 2018 at 07:24:12PM CET, alexander.du...@gmail.com wrote: >On Sat, Mar 3, 2018 at 11:13 PM, Jiri Pirko <j...@resnulli.us> wrote: >> Sun, Mar 04, 2018 at 01:26:53AM CET, alexander.du...@gmail.com wrote: >>>On Sat, Mar 3, 2018 at 1:25 PM, Jiri Pirko <j...@resnulli.us> wrote: >>>> Sat, Mar 03, 2018 at 07:04:57PM CET, alexander.du...@gmail.com wrote: >>>>>On Sat, Mar 3, 2018 at 3:31 AM, Jiri Pirko <j...@resnulli.us> wrote: >>>>>> Fri, Mar 02, 2018 at 08:42:47PM CET, m...@redhat.com wrote: >>>>>>>On Fri, Mar 02, 2018 at 05:20:17PM +0100, Jiri Pirko wrote: >>>>>>>> >Yeah, this code essentially calls out the "shareable" code with a >>>>>>>> >comment at the start and end of the section what defines the >>>>>>>> >virtio_bypass functionality. It would just be a matter of mostly >>>>>>>> >cutting and pasting to put it into a separate driver module. >>>>>>>> >>>>>>>> Please put it there and unite the use of it with netvsc. >>>>>>> >>>>>>>Surely, adding this to other drivers (e.g. might this be handy for xen >>>>>>>too?) can be left for a separate patchset. Let's get one device merged >>>>>>>first. >>>>>> >>>>>> Why? Let's do the generic infra alongside with the driver. I see no good >>>>>> reason to rush into merging driver and only later, if ever, to convert >>>>>> it to generic solution. On contrary. That would lead into multiple >>>>>> approaches and different behavious in multiple drivers. That is plain >>>>>> wrong. >>>>> >>>>>If nothing else it doesn't hurt to do this in one driver in a generic >>>>>way, and once it has been proven to address all the needs of that one >>>>>driver we can then start moving other drivers to it. The current >>>>>solution is quite generic, that was my contribution to this patch set >>>>>as I didn't like how invasive it was being to virtio and thought it >>>>>would be best to keep this as minimally invasive as possible. >>>>> >>>>>My preference would be to give this a release or two in virtio to >>>>>mature before we start pushing it onto other drivers. It shouldn't >>>>>take much to cut/paste this into a new driver file once we decide it >>>>>is time to start extending it out to other drivers. >>>> >>>> I'm not talking about cut/paste and in fact that is what I'm worried >>>> about. I'm talking about common code in net/core/ or somewhere that >>>> would take care of this in-driver bonding. Each driver, like virtio_net, >>>> netvsc would just register some ops to it and the core would do all >>>> logic. I believe it is essential take this approach from the start. >>> >>>Sorry, I didn't mean cut/paste into another driver, I meant to make it >>>a driver of its own. My thought was to eventually create a shared/core >>>driver module that is then used by the other drivers. >>> >>>My concern right now is that Stephen has indicated he doesn't want >>>this approach taken with netvsc, and most of the community doesn't >> >> IIUC, he only does not like the extra netdev. Is there anything else? > >Nope that is pretty much it. It doesn't seem like a big deal for >virtio, but for netvsc it is significant since they don't have any >"backup" bit feature differentiation, so they would likely be stuck >with 2 netdevs even in their basic setup.
Okay. If that is a strict "no-go" for netvsc, this should be just a flag passed down to the in-driver bond code. > >>>want the netvsc approach applied to virtio. Until that impasse can be >>>resolved there isn't much value in trying to split this up so it is >>>available to other drivers. In addition I would imagine it would make >>>it a pain for others to back-port into distros since it would break >>>legacy netvsc driver behavior. Patches are always welcome. Once this >>>is in you are free to try fighting to get this made into a generic >>>module and applied to both drivers, but we have already spent close to >>>3 months on this and it seems like there has been significantly more >> >> Alex, time is never a good argument for poor design and shortcuts. > >I'm not saying we should go with a poor design due to time. But >expecting us to implement something where the maintainer of said >driver has not agreed to is pointless, and I don't see it as a design He just does not like the third netdev, not the fact that the code for in-driver bonding would be shared. >shortcut to implement something in one driver with the expectation >that we will then make it core later once it has proven itself and has >use elsewhere. In the meantime I would imagine it also makes it easier >for things like backports and such for us to do it this way since we >are only impacting one driver. When you are working on upstream kernel, you should not care about backports. That leads to poor design. Not an argument. > >You are telling us to do something that not everyone has agreed to. Who did not? >Currently we only have agreement from Michael on taking this code, as >such we are working with virtio only for now. When the time comes that If you do duplication of netvsc in-driver bonding in virtio_net, it will stay there forever. So what you say is: "We will do it halfway now and promise to fix it later". That later will never happen, I'm pretty sure. That is why I push for in-driver bonding shared code as a part of this patchset. + if you would be pushing first driver to do this, I would understand. But the first driver is already in. You are pushing second. This is the time to do the sharing, unification of behaviour. Next time is too late. >we can get other maintainers, specifically Stephen, to agree to it >then we can cut/paste this code into a core file or into a module of >its own. Alternatively I suppose we could take this up to Dave if you >can't get Stephen to agree. If you can get Dave to say we need to >change netvsc then we will go ahead with it, but generally I prefer to >respect when the maintainer of something says they don't want us >modifying their code in some way.
