On Wed, Aug 16, 2017 at 09:02:31AM +0000, Matan Azrad wrote:
> Hi Gaetan
>
> > -----Original Message-----
> > From: Gaëtan Rivet [mailto:gaetan.ri...@6wind.com]
> > Sent: Wednesday, August 16, 2017 11:47 AM
> > To: Matan Azrad <ma...@mellanox.com>
> > Cc: dev@dpdk.org; sta...@dpdk.org
> > Subject: Re: [PATCH] net/failsafe: fix tx sub device deactivating
> >
> > Hi Matan,
> >
> > Thanks for spotting this, a few nits below.
> >
> > On Tue, Aug 15, 2017 at 09:59:19AM +0300, Matan Azrad wrote:
> > > The corrupted code couldn't recognize that all sub devices were not
> > > ready for tx traffic when failsafe PMD was trying to switch device
> > > because of an unreachable condition using.
> > >
> > > Hence, the current tx sub device variable was not updated correctly.
> > >
> > > The fix removed the unreachable condition and adds condition in the
> > > right place to handle non tx device ready scenario.
> > >
> >
> > It should be reworded as
> >
> > Make the condition reachable by moving it in the right place to
> > handle the scenario when no TX device is ready.
> >
> > If the condition is removed and then added, I find it clearer to say that
> > it was
> > moved.
>
> But the two conditions are different,
> The old condition can't handle the scenario we want.
>
Yes you're right, but the commit log should still be written in the
present tense:
Remove the unreachable branch and add one in the right place respecting
the original intent.
Or something like it :)
> >
> > > Fixes: ebea83f899d8 ("net/failsafe: add plug-in support")
> > > Fixes: 598fb8aec6f6 ("net/failsafe: support device removal")
> > >
> >
> > The root commit introducing the issue is the first one, but this fix only
> > applies
> > to the second.
> > So I don't know which commit is actually fixed by this, but I find peculiar
> > to
> > have two commits targeted by a fix.
> >
> > In doubt, probably leave both, but maybe someone has a better idea about
> > it?
>
> I also thought about it, and found the two are necessary for future review.
>
> >
> > > Signed-off-by: Matan Azrad <ma...@mellanox.com>
> > > Cc: sta...@dpdk.org
> >
> > The Cc: stable line should immediately follow the Fixes: line.
> >
>
> Will be fixed.
>
> > > ---
> > > drivers/net/failsafe/failsafe_private.h | 7 ++++---
> > > 1 file changed, 4 insertions(+), 3 deletions(-)
> > >
> > > Hi Gaetan
> > > I didn't find any real scenario which cause to problematic behavior
> > > because of the previous code.
> > > But it may be.
> > >
> > > diff --git a/drivers/net/failsafe/failsafe_private.h
> > > b/drivers/net/failsafe/failsafe_private.h
> > > index 0361cf4..dc97aec 100644
> > > --- a/drivers/net/failsafe/failsafe_private.h
> > > +++ b/drivers/net/failsafe/failsafe_private.h
> > > @@ -346,9 +346,10 @@ fs_switch_dev(struct rte_eth_dev *dev,
> > > PRIV(dev)->subs_tx = i;
> > > break;
> > > }
> > > - } else if (txd && txd->state < req_state) {
> > > - DEBUG("No device ready, deactivating tx_dev");
> > > - PRIV(dev)->subs_tx = PRIV(dev)->subs_tail;
> > > + if (i >= PRIV(dev)->subs_tail || !sdev) {
> >
> > `!sdev` should be `sdev == NULL`, see [1].
> OK, will be fixed.
>
> >
> > > + DEBUG("No device ready, deactivating tx_dev");
> > > + PRIV(dev)->subs_tx = PRIV(dev)->subs_tail;
> > > + }
> > > } else {
> > > return;
> > > }
> > > --
> > > 2.7.4
> > >
> >
> > With these changes,
> >
> > Acked-by: Gaetan Rivet <gaetan.ri...@6wind.com>
> >
> > [1]:
> > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdpd
> > k.org%2Fdoc%2Fguides%2Fcontributing%2Fcoding_style.html%23c-
> > statement-style-and-
> > conventions&data=02%7C01%7Cmatan%40mellanox.com%7C6283c71dcc2b4
> > ebe5f6608d4e48350cd%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%
> > 7C636384700025293702&sdata=nNMTElzhe3RlEMc3vB67QlwAYYYQ%2ByNNp
> > 9ebXgSsMM8%3D&reserved=0
> > --
> > Gaëtan Rivet
> > 6WIND
>
> Thanks
> Matan Azrad
--
Gaëtan Rivet
6WIND
