linux-kernel - Re: [PATCH net-next v19 03/13] netdev: support binding dma-buf to netdevice

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Message-ID: <CAHS8izN0Wb7isGbhO+cvYNfG+v2bsvvfy7P0cSsMD7USfd+4bQ@mail.gmail.com>
Date: Fri, 16 Aug 2024 09:56:36 -0400
From: Mina Almasry <almasrymina@...gle.com>
To: Jakub Kicinski <kuba@...nel.org>
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Subject: Re: [PATCH net-next v19 03/13] netdev: support binding dma-buf to netdevice

On Thu, Aug 15, 2024 at 8:48 PM Jakub Kicinski <kuba@...nel.org> wrote:
>
> On Tue, 13 Aug 2024 21:13:05 +0000 Mina Almasry wrote:
> > +int dev_get_max_mp_channel(const struct net_device *dev)
> > +{
> > +     int i, max = -1;
>
> I presume the bug from yesterday is self evident once reported? :)
>

Yes, my apologies. The int return value from this function was being
implicitly cast to unsigned in the check I think, and that failed the
check.

My test didn't catch that due to a test environment issue. I had 2
ethtools installed by accident on the machine, and the test was
invoking the wrong one. I think I have that ironed out now.

> > +     ASSERT_RTNL();
> > +
> > +     for (i = 0; i < dev->real_num_rx_queues; i++)
> > +             if (dev->_rx[i].mp_params.mp_priv)
> > +                     /* The number of queues is the idx plus 1. */
> > +                     max = i + 1;
>
> The +1 is odd. The function as it stands reports min channel count.
> Not max_mp_channel, if you ask me. And if you renamed it, you don't
> have to use -1 as "not installed".
>

Will do.

--
Thanks,
Mina