Re: [PATCH 2/4 net] qca_spi: Fix SPI IRQ handling

On Fri, 2023-11-24 at 15:01 +0100, Stefan Wahren wrote:

Hi Paolo,

Am 23.11.23 um 12:37 schrieb Paolo Abeni:

quoted

On Tue, 2023-11-21 at 17:30 +0100, Stefan Wahren wrote:

quoted

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.

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.

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(). 

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

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