Re: [PATCH 2/2] spi: spi-fsl-dspi: Initialize completion before possible interrupt

[Krzysztof Kozlowski]

On Sun, Jun 14, 2020 at 02:14:15PM +0300, Vladimir Oltean wrote:
> On Sun, 14 Jun 2020 at 13:56, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> >
> > If interrupt fires early, the dspi_interrupt() could complete
> > (dspi->xfer_done) before its initialization happens.
> >
> > Fixes: 4f5ee75ea171 ("spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion")
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > ---
> 
> Why would an interrupt fire before spi_register_controller, therefore
> before dspi_transfer_one_message could get called?
> Is this master or slave mode?

I guess practically it won't fire.  It's more of a matter of logical
order and:
1. Someone might fix the CONFIG_DEBUG_SHIRQ_FIXME one day,
2. The hardware is actually initialized before and someone could attach
   to SPI bus some weird device.

Best regards,
Krzysztof