linux-kernel - Re: [PATCH V3 20/21] pci, acpi: Match PCI config space accessors against platfrom specific quirks.

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Message-ID: <569CDD8F.807@semihalf.com>
Date:	Mon, 18 Jan 2016 13:41:51 +0100
From:	Tomasz Nowicki <tn@...ihalf.com>
To:	Mark Salter <msalter@...hat.com>, bhelgaas@...gle.com,
	arnd@...db.de, will.deacon@....com, catalin.marinas@....com,
	rjw@...ysocki.net, hanjun.guo@...aro.org,
	Lorenzo.Pieralisi@....com, okaya@...eaurora.org,
	jiang.liu@...ux.intel.com, Stefano.Stabellini@...citrix.com
Cc:	robert.richter@...iumnetworks.com, mw@...ihalf.com,
	Liviu.Dudau@....com, ddaney@...iumnetworks.com, tglx@...utronix.de,
	wangyijing@...wei.com, Suravee.Suthikulpanit@....com,
	linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	linaro-acpi@...ts.linaro.org, jchandra@...adcom.com, jcm@...hat.com
Subject: Re: [PATCH V3 20/21] pci, acpi: Match PCI config space accessors
 against platfrom specific quirks.

On 14.01.2016 16:36, Mark Salter wrote:
>> +extern struct pci_mcfg_fixup __start_acpi_mcfg_fixups[];
>> >+extern struct pci_mcfg_fixup __end_acpi_mcfg_fixups[];
>> >+
>> >+static struct pci_ops *pci_mcfg_check_quirks(struct acpi_pci_root *root)
>> >+{
>> >+	struct pci_mcfg_fixup *f;
>> >+	int bus_num = root->secondary.start;
>> >+	int domain = root->segment;
>> >+
>> >+	/*
>> >+	 * First match against PCI topology <domain:bus> then use DMI or
>> >+	 * custom match handler.
>> >+	 */
>> >+	for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; f++) {
>> >+		if ((f->domain == domain || f->domain == PCI_MCFG_DOMAIN_ANY) &&
>> >+		    (f->bus_num == bus_num || f->bus_num == PCI_MCFG_BUS_ANY) &&
>> >+		    (f->system ? dmi_check_system(f->system) : 0 ||
>> >+		     f->match ? f->match(f, root) : 0))
>> >+			return f->ops;
> I think this would be better as:
>
> 		    (f->system ? dmi_check_system(f->system) : 1 &&
> 		     f->match ? f->match(f, root) : 1))
> 			return f->ops;
>
> Otherwise, one has to call dmi_check_system() from f->match() if
> access to root is needed.

Makes a lot of sense to me, I will modify as you suggested.

Tomasz