Re: [PATCH net-next v8 0/4] send credit update during setting SO_RCVLOWAT

[Stefano Garzarella]

On Wed, Dec 13, 2023 at 12:08:27PM +0300, Arseniy Krasnov wrote:
> On 13.12.2023 11:43, Stefano Garzarella wrote:
> > On Tue, Dec 12, 2023 at 08:43:07PM +0300, Arseniy Krasnov wrote:
> > > On 12.12.2023 19:12, Michael S. Tsirkin wrote:
> > > > On Tue, Dec 12, 2023 at 06:59:03PM +0300, Arseniy Krasnov wrote:
> > > > > On 12.12.2023 18:54, Michael S. Tsirkin wrote:
> > > > > > On Tue, Dec 12, 2023 at 12:16:54AM +0300, Arseniy Krasnov wrote:
> > > > > > > Hello,
> > > > > > >
> > > > > > >                                DESCRIPTION
> > > > > > >
> > > > > > > This patchset fixes old problem with hungup of both rx/tx sides and adds
> > > > > > > test for it. This happens due to non-default SO_RCVLOWAT value and
> > > > > > > deferred credit update in virtio/vsock. Link to previous old patchset:
> > > > > > > https://lore.kernel.org/netdev/39b2e9fd-601b-189d-39a9-914e5574524c@xxxxxxxxxxxxxx/
> > > > > >
> > > > > >
> > > > > > Patchset:
> > > > > >
> > > > > > Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > > > >
> > > > > Thanks!
> > > > >
> > > > > > But I worry whether we actually need 3/8 in net not in net-next.
> > > > >
> > > > > Because of "Fixes" tag ? I think this problem is not critical and reproducible
> > > > > only in special cases, but i'm not familiar with netdev process so good, so I don't
> > > > > have strong opinion. I guess @Stefano knows better.
> > > > >
> > > > > Thanks, Arseniy
> > > >
> > > > Fixes means "if you have that other commit then you need this commit
> > > > too". I think as a minimum you need to rearrange patches to make the
> > > > fix go in first. We don't want a regression followed by a fix.
> > >
> > > I see, ok, @Stefano WDYT? I think rearrange doesn't break anything, because this
> > > patch fixes problem that is not related with the new patches from this patchset.
> >
> > I agree, patch 3 is for sure net material (I'm fine with both rearrangement or send it separately), but IMHO also patch 2 could be.
> > I think with the same fixes tag, since before commit b89d882dc9fc ("vsock/virtio: reduce credit update messages") we sent a credit update
> > for every bytes we read, so we should not have this problem, right?
>
> Agree for 2, so I think I can rearrange: two fixes go first, then current 0001, and then tests. And send it as V9 for 'net' only ?

Maybe you can add this to patch 1 if we want it on net:

Fixes: e38f22c860ed ("vsock: SO_RCVLOWAT transport set callback")

Then I think that patch should go before patch 2, so we don't need to
touch that code multiple times.

so, IMHO the order should be the actual order or 3 - 1 - 2 - 4.

Another option is to send just 2 & 3 to net, and the rest (1 & 4) to 
net-next. IMHO should be fine to send the entire series to net with the 
fixes tag also in patch 1.

Net maintainers and Michael might have a different advice.

Thanks,
Stefano