Received-SPF: pass (google.com: domain of linux-kernel+bounces-152897-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: Andy Shevchenko <andy.shevchenko@gmail.com>
Date: Mon, 22 Apr 2024 10:45:46 +0300
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Vidya Sagar <vidyas@nvidia.com>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Len Brown <lenb@kernel.org>, Will Deacon <will@kernel.org>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
	Rob Herring <robh@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Thierry Reding <treding@nvidia.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Krishna Thota <kthota@nvidia.com>,
	Manikanta Maddireddy <mmaddireddy@nvidia.com>,
	Vidya Sagar <sagar.tv@gmail.com>, linux-pci@vger.kernel.org,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH v7-incomplete 1/3] PCI: Move PRESERVE_BOOT_CONFIG _DSM
 evaluation to pci_register_host_bridge()
Message-ID: <ZiYVqulm8cE_FGKx@surfacebook.localdomain>
References: <20240418174043.3750240-1-vidyas@nvidia.com>
 <20240421190914.374399-1-helgaas@kernel.org>
 <20240421190914.374399-2-helgaas@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240421190914.374399-2-helgaas@kernel.org>

Sun, Apr 21, 2024 at 02:09:12PM -0500, Bjorn Helgaas kirjoitti:
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> Move the PRESERVE_BOOT_CONFIG _DSM evaluation from acpi_pci_root_create()
> to pci_register_host_bridge().
> 
> This will help unify the ACPI _DSM path and the DT-based
> "linux,pci-probe-only" paths.

..

> +bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
> +{
> +	if (ACPI_HANDLE(&host_bridge->dev)) {

Wouldn't the below looks nicer if you invert the conditional?

	handle = ACPI_HANDLE(...);

	if (!handle)
		return false;

	...

> +		union acpi_object *obj;
> +
> +		/*
> +		 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
> +		 * exists and returns 0, we must preserve any PCI resource
> +		 * assignments made by firmware for this host bridge.
> +		 */
> +		obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&host_bridge->dev),
> +					      &pci_acpi_dsm_guid,
> +					      1, DSM_PCI_PRESERVE_BOOT_CONFIG,
> +					      NULL, ACPI_TYPE_INTEGER);
> +		if (obj && obj->integer.value == 0)
> +			return true;
> +		ACPI_FREE(obj);
> +	}
> +
> +	return false;
> +}


-- 
With Best Regards,
Andy Shevchenko