netdev - Re: [PATCH net 1/2] net: ipa: directly disable ipa-setup-ready interrupt

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Message-ID: <YZ6GTe3wUU7PbI/W@google.com>
Date:   Wed, 24 Nov 2021 10:37:01 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Alex Elder <elder@...aro.org>
Cc:     davem@...emloft.net, kuba@...nel.org, pkurapat@...eaurora.org,
        avuyyuru@...eaurora.org, bjorn.andersson@...aro.org,
        cpratapa@...eaurora.org, subashab@...eaurora.org,
        evgreen@...omium.org, elder@...nel.org, netdev@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net 1/2] net: ipa: directly disable ipa-setup-ready
 interrupt

On Mon, Nov 22, 2021 at 06:15:54PM -0600, Alex Elder wrote:
> We currently maintain a "disabled" Boolean flag to determine whether
> the "ipa-setup-ready" SMP2P IRQ handler does anything.  That flag
> must be accessed under protection of a mutex.
> 
> Instead, disable the SMP2P interrupt when requested, which prevents
> the interrupt handler from ever being called.  More importantly, it
> synchronizes a thread disabling the interrupt with the completion of
> the interrupt handler in case they run concurrently.
> 
> Use the IPA setup_complete flag rather than the disabled flag in the
> handler to determine whether to ignore any interrupts arriving after
> the first.
> 
> Rename the "disabled" flag to be "setup_disabled", to be specific
> about its purpose.
> 
> Fixes: 530f9216a953 ("soc: qcom: ipa: AP/modem communications")
> Signed-off-by: Alex Elder <elder@...aro.org>

I don't claim to know much about IPA, but this looks reasonable to me.

Reviewed-by: Matthias Kaehlcke <mka@...omium.org>