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Re: [Xen-devel] [PATCH v2 03/22] MSI: Remove the redundant irq_set_chip_data()

On 2014/9/25 15:19, Thierry Reding wrote:
> On Thu, Sep 25, 2014 at 11:14:13AM +0800, Yijing Wang wrote:
>> Currently, pcie-designware, pcie-rcar, pci-tegra drivers
>> use irq chip_data to save the msi_chip pointer. They
>> already call irq_set_chip_data() in their own MSI irq map
>> functions. So irq_set_chip_data() in arch_setup_msi_irq()
>> is useless.
> Again, I think this should be the other way around. If drivers do
> something that's already handled by the core, then the duplicate code
> should be dropped from the drivers.

Hi Thierry, this is different thing, because chip_data is specific to IRQ
controller, and in other platform, like in x86, chip_data is used to save 
So we can not call irq_set_chip_data() in core code.

x86 irq piece code

int arch_setup_hwirq(unsigned int irq, int node)
        struct irq_cfg *cfg;
        unsigned long flags;
        int ret;

        cfg = alloc_irq_cfg(irq, node);
        if (!cfg)
                return -ENOMEM;

        raw_spin_lock_irqsave(&vector_lock, flags);
        ret = __assign_irq_vector(irq, cfg, apic->target_cpus());
        raw_spin_unlock_irqrestore(&vector_lock, flags);

        if (!ret)
                irq_set_chip_data(irq, cfg);  ------------->Save irq_cfg
                free_irq_cfg(irq, cfg);
        return ret;


> Thierry


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