Re: [RFC PATCH V2 1/8] irqdomain: Ensure type settings match for an existing mapping

From: Linus Walleij <linus.walleij@linaro.org>
To: Jon Hunter <jonathanh@nvidia.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Jiang Liu <jiang.liu@linux.intel.com>,
	Stephen Warren <swarren@wwwdotorg.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Kevin Hilman <khilman@kernel.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Soren Brinkmann <soren.brinkmann@xilinx.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
Subject: Re: [RFC PATCH V2 1/8] irqdomain: Ensure type settings match for an existing mapping
Date: Tue, 22 Dec 2015 10:58:24 +0100	[thread overview]
Message-ID: <CACRpkdbjRiW8gcZcifHLELjBukpsCKyTQ+NpP51+v3kYLDcPHA@mail.gmail.com> (raw)
In-Reply-To: <5673DB87.6040106@nvidia.com>

On Fri, Dec 18, 2015 at 11:10 AM, Jon Hunter <jonathanh@nvidia.com> wrote:
> On 17/12/15 13:16, Linus Walleij wrote:
>> On Thu, Dec 17, 2015 at 11:48 AM, Jon Hunter <jonathanh@nvidia.com> wrote:
>>> +               } else {
>>> +                       virq = irq_domain_alloc_descs(-1, 1, hwirq,
>>> +                                                     of_node_to_nid(of_node));
>>
>> What is this all of a sudden? Not even mentioned in the
>> commit. Plus I bet ACPI need something else than OF nid
>> passed here.
>
> Do you mean the else part of all of the above?

Yes

> So in the current code, the else part calls irq_create_mapping() (...)

No, not that... The fact that you all of a sudden have started
calling irq_domain_alloc_descs() which the function didn't do
before, totally changing the calling semantics for everyone in
the kernel, leading to the problem I then describe with this
potentially being called before the irqdomain for the irqchip
is initialized and descs getting "random" numbers.

Yours,
Linus Walleij