netdev - Re: [PATCH net-next v2 07/12] net: dpaa2-eth: use dev_close/open instead of the internal functions

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Date:   Tue, 27 Sep 2022 13:45:08 +0000
From:   Ioana Ciornei <ioana.ciornei@....com>
To:     Paolo Abeni <pabeni@...hat.com>
CC:     "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>
Subject: Re: [PATCH net-next v2 07/12] net: dpaa2-eth: use dev_close/open
 instead of the internal functions

On Tue, Sep 27, 2022 at 02:54:58PM +0200, Paolo Abeni wrote:
> On Fri, 2022-09-23 at 18:45 +0300, Ioana Ciornei wrote:
> > Instead of calling the internal functions which implement .ndo_stop and
> > .ndo_open, we can simply call dev_close and dev_open, so that we keep
> > the code cleaner.
> > 
> > Also, in the next patches we'll use the same APIs from other files
> > without needing to export the internal functions.
> > 
> > Signed-off-by: Ioana Ciornei <ioana.ciornei@....com>
> 
> This has the not so nice side effect that in case of dev_open() error,
> the device will flip status after dpaa2_eth_setup_xdp(). We should try
> to avoid that.
> 
> I think it's better if you export the helper instead (or even better,
> do something more low level-cant-fail like stop the relevant h/w queue,
> reconfigure, restart the h/w queue).
> 

I would also have wanted to not have to stop the entire interface but
unfortunately this is not possible.
In order to change which buffer pool is used on which queue I have to
stop the interface (dpni_disable() ) which would flip the link.

I can export the helpers but this would not change the behavior since
the dpaa2_eth_stop() and dpaa2_eth_open() are the exact callbacks
setup for .ndo_stop() and .ndo_open().

Ioana