linux-kernel - Re: [PATCH 4/4] firmware: qcom: scm: request the waitqueue irq *after* initializing SCM

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Message-ID: <c189e03f-a3a7-422e-a156-ecfae92a7443@oss.qualcomm.com>
Date: Wed, 25 Jun 2025 16:49:38 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Bartosz Golaszewski <brgl@...ev.pl>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 4/4] firmware: qcom: scm: request the waitqueue irq
 *after* initializing SCM

On 6/25/25 10:14 AM, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> There's a subtle race in the SCM driver: we assign the __scm pointer
> before requesting the waitqueue interrupt. Assigning __scm marks the SCM
> API as ready to accept calls. It's possible that a user makes a call
> right after we set __scm and the firmware raises an interrupt before the
> driver's ready to service it. Move the __scm assignment after we request
> the interrupt.
> 
> This has the added benefit of allowing us to drop the goto label.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---

I don't think there's a suitable reference for a Fixes there,
so let's skip it

Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Konrad