Re: [dpdk-dev] [PATCH v2 02/10] kni: separate releasing netdev from freeing KNI interface

[Dan Gora <dg@adax.com>]

I'll have a look at this.. Maybe it will work, I'll have to try it and
test it to see if there are any gotchas that are not obvious.

d

On Wed, Oct 10, 2018 at 7:51 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> >> Very simply, what about prevent kni_net_release() send callback to userspace?
> >
> > No, because how is the DPDK application going to know when the user
> > does 'ip link set down dev <kniX>'?   It's important for the DPDK
> > application to know when the KNI interface is marked down.
>
> I mean kni_net_release() called because of unregister_netdev(),
>
> it is possible to set a flag in kni_dev_remove(), before unregister_netdev(),
> and in kni_net_release() don't call kni_net_process_request() if flag is set.
>
> Looks like it can work and only a few lines of code, what do you think?
>
> >
> >> This is already not working and removing it resolves the issues you mentioned.
> >
> > Huh?  How is it not working?  Of course it works.
>
> The kni_net_release() called because of unregister_netdev() is not working, as
> you explained in userspace the thread handles request already terminated, even
> if not in kernel side response not received and timed off because of lock...
>
> >
> >> Sample application calls rte_eth_dev_stop() after release itself, so behavior
> >> will be same.
> >
> > Huh?
>
> in kni sample app, in kni_free_kni() rte_eth_dev_stop() is called after
> rte_kni_release().
> So if you prevent kni_net_release() called because of unregister_netdev() to
> send callback it won't be problem because of existing rte_eth_dev_stop()
>