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References: <20221205084127.535-1-xieyongji@bytedance.com> <20221205084127.535-2-xieyongji@bytedance.com>
 <20221206081847.GA8771@lst.de>
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From:   Yongji Xie <xieyongji@bytedance.com>
Date:   Tue, 6 Dec 2022 16:40:37 +0800
Message-ID: <CACycT3sXHGQt_V=rgwvEv4v8+oUaAOu1T=tWrKePdybMHagzng@mail.gmail.com>
Subject: Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
To:     Christoph Hellwig <hch@lst.de>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        virtualization <virtualization@lists.linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Tue, Dec 6, 2022 at 4:18 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Mon, Dec 05, 2022 at 04:41:17PM +0800, Xie Yongji wrote:
> > Export irq_create_affinity_masks() so that some modules
> > can make use of it to implement interrupt affinity
> > spreading mechanism.
>
> I don't think driver should be building low-level affinity masks.

With the vDPA framework, some drivers (vduse, vdpa-sim) can create
software-defined virtio devices and attach them to the virtio bus.
This kind of virtio device is not a pci device or a platform device.
So it would be needed to export this function if we want to implement
the automatic affinity management for the virtio device driver which
is binded to this device.

Thanks,
Yongji