linux-kernel - Re: [PATCH v2 12/12] reboot: retire hw_protection_reboot and hw_protection

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Message-ID: <Z433h78ahaT2d5Qe@google.com>
Date: Mon, 20 Jan 2025 07:13:11 +0000
From: Tzung-Bi Shih <tzungbi@...nel.org>
To: Ahmad Fatoum <a.fatoum@...gutronix.de>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Fabio Estevam <festevam@...x.de>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Zhang Rui <rui.zhang@...el.com>, Lukasz Luba <lukasz.luba@....com>,
	Jonathan Corbet <corbet@....net>, Serge Hallyn <serge@...lyn.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Matti Vaittinen <mazziesaccount@...il.com>,
	Benson Leung <bleung@...omium.org>,
	Guenter Roeck <groeck@...omium.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	chrome-platform@...ts.linux.dev, devicetree@...r.kernel.org,
	kernel@...gutronix.de
Subject: Re: [PATCH v2 12/12] reboot: retire hw_protection_reboot and
 hw_protection_shutdown helpers

On Mon, Jan 13, 2025 at 05:25:37PM +0100, Ahmad Fatoum wrote:
> The hw_protection_reboot and hw_protection_shutdown functions mix
> mechanism with policy: They let the driver requesting an emergency
> action for hardware protection also decide how to deal with it.
> 
> This is inadequate in the general case as a driver reporting e.g. an
> imminent power failure can't know whether a shutdown or a reboot would
> be more appropriate for a given hardware platform.
> 
> With the addition of the hw_protection parameter, it's now possible to
> configure at runtime the default emergency action and drivers are
> expected to use hw_protection_trigger to have this parameter dictate
> policy.
> 
> As no current users of either hw_protection_shutdown or
> hw_protection_shutdown helpers remain, remove them, as not to tempt
> driver authors to call them.
> 
> Existing users now either defer to hw_protection_trigger or call
> __hw_protection_trigger with a suitable argument directly when
> they have inside knowledge on whether a reboot or shutdown would
> be more appropriate.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@...gutronix.de>

Reviewed-by: Tzung-Bi Shih <tzungbi@...nel.org>