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Message-ID: <9e2bba3c98cd24ebf1b6d9fde2e0b9229ad6b99f.camel@redhat.com>
Subject: Re: [PATCH 2/4 net] qca_spi: Fix SPI IRQ handling
From:   Paolo Abeni <pabeni@redhat.com>
To:     Stefan Wahren <wahrenst@gmx.net>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     Lino Sanfilippo <LinoSanfilippo@gmx.de>,
        Florian Fainelli <f.fainelli@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Fri, 24 Nov 2023 16:33:04 +0100
In-Reply-To: <bf3dd03e-a1f2-4586-8f00-7003848016aa@gmx.net>
References: <20231121163004.21232-1-wahrenst@gmx.net>
         <20231121163004.21232-3-wahrenst@gmx.net>
         <a24433f86e39cbb45a9606621e01446e7ad6fa53.camel@redhat.com>
         <bf3dd03e-a1f2-4586-8f00-7003848016aa@gmx.net>
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On Fri, 2023-11-24 at 15:01 +0100, Stefan Wahren wrote:
> Hi Paolo,
>=20
> Am 23.11.23 um 12:37 schrieb Paolo Abeni:
> > On Tue, 2023-11-21 at 17:30 +0100, Stefan Wahren wrote:
> > > The functions qcaspi_netdev_open/close are responsible of request &
> > > free of the SPI interrupt, which wasn't the best choice. Currently
> > > it's possible to trigger a double free of the interrupt by calling
> > > qcaspi_netdev_close() after qcaspi_netdev_open() has failed.
> > > So let us split IRQ allocation & enabling, so we can take advantage
> > > of a device managed IRQ and also fix the issue.
> > >=20
> > > Fixes: 291ab06ecf67 ("net: qualcomm: new Ethernet over SPI driver for=
 QCA7000")
> > > Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> > The change makes sense, but the changelog is confusing.
> >=20
> > qcaspi_netdev_close() and qcaspi_netdev_open() are invoked only via
> > ndo_open and ndo_close(), right? So qcaspi_netdev_close() will never be
> > invoked qcaspi_netdev_open(), failure - that is when IFF_UP is not set.
> sorry, i missed to mention an important part. This issue is partly
> connected to patch 3.
> Please look at qcaspi_set_ringparam() which also call ndo_close() and
> ndo_open().=C2=A0

Ah, I see it now. IMHO root cause of the problem is there. The ethtool
op should not flip the device state.=C2=A0

A more narrow fix would be to park/unpark the thread inside
set_ringparam() - instead of the whole patch 1 && 2 I suspect.

IMHO the changes in this still make sense - a refactor for net-next.

Cheers,

Paolo