Re: FAILED: patch "[PATCH] iio: adc: stm32-adc: fix a race when using several adcs with" failed to apply to 4.19-stable tree

[Sasha Levin <sashal@kernel.org>]

On Mon, Oct 14, 2019 at 05:58:16PM +0200, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.19-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From dcb10920179ab74caf88a6f2afadecfc2743b910 Mon Sep 17 00:00:00 2001
>From: Fabrice Gasnier <fabrice.gasnier@st.com>
>Date: Tue, 17 Sep 2019 14:38:16 +0200
>Subject: [PATCH] iio: adc: stm32-adc: fix a race when using several adcs with
> dma and irq
>
>End of conversion may be handled by using IRQ or DMA. There may be a
>race when two conversions complete at the same time on several ADCs.
>EOC can be read as 'set' for several ADCs, with:
>- an ADC configured to use IRQs. EOCIE bit is set. The handler is normally
>  called in this case.
>- an ADC configured to use DMA. EOCIE bit isn't set. EOC triggers the DMA
>  request instead. It's then automatically cleared by DMA read. But the
>  handler gets called due to status bit is temporarily set (IRQ triggered
>  by the other ADC).
>So both EOC status bit in CSR and EOCIE control bit must be checked
>before invoking the interrupt handler (e.g. call ISR only for
>IRQ-enabled ADCs).
>
>Fixes: 2763ea0585c9 ("iio: adc: stm32: add optional dma support")
>
>Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
>Cc: <Stable@vger.kernel.org>
>Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

It would be nice if a stable patch wouldn't depend on a massive code
movement patch...

Anyway, I ported both to 4.19 as it was just a minor missing dependency,
but 4.14 requires more work I'll leave to someone who knows that code
better than me.

-- 
Thanks,
Sasha