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Subject: Re: [PATCH v2 1/2] genirq: add an irq_create_mapping_affinity()
 function
To:     Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org
Cc:     linux-block@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
        linux-pci@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
        linuxppc-dev@lists.ozlabs.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        "Michael S . Tsirkin" <mst@redhat.com>, Greg Kurz <groug@kaod.org>,
        Christoph Hellwig <hch@lst.de>,
        Michael Ellerman <mpe@ellerman.id.au>
References: <20201125111657.1141295-1-lvivier@redhat.com>
 <20201125111657.1141295-2-lvivier@redhat.com>
 <87sg8xk1yi.fsf@nanos.tec.linutronix.de>
From:   Laurent Vivier <lvivier@redhat.com>
Message-ID: <e32641f7-0993-8923-7d74-5ac57a60f10d@redhat.com>
Date:   Wed, 25 Nov 2020 15:09:42 +0100
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On 25/11/2020 14:20, Thomas Gleixner wrote:
> Laurent,
> 
> On Wed, Nov 25 2020 at 12:16, Laurent Vivier wrote:
> 
> The proper subsystem prefix is: 'genirq/irqdomain:' and the first letter
> after the colon wants to be uppercase.

Ok.

>> This function adds an affinity parameter to irq_create_mapping().
>> This parameter is needed to pass it to irq_domain_alloc_descs().
> 
> A changelog has to explain the WHY. 'The parameter is needed' is not
> really useful information.
> 

The reason of this change is explained in PATCH 2.

I have two patches, one to change the interface with no functional change (PATCH 1) and
one to fix the problem (PATCH 2). Moreover they don't cover the same subsystems.

I can either:
- merge the two patches
- or make a reference in the changelog of PATCH 1 to PATCH 2
  (something like "(see folowing patch "powerpc/pseries: pass MSI affinity to
   irq_create_mapping()")")
- or copy some information from PATCH 2
  (something like "this parameter is needed by rtas_setup_msi_irqs() to pass the affinity
   to irq_domain_alloc_descs() to fix multiqueue affinity")

What do you prefer?

Thanks,
Laurent