Re: [PATCH 2/2] x86_64 irq: Only look at per_cpu data for online cpus.

[yhlu]

On 10/22/06, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
> When I generalized __assign_irq_vector I failed to pay attention
> to what happens when you access a per cpu data structure for
> a cpu that is not online.   It is an undefined case making any
> code that does it have undefined behavior as well.
>
> The code still needs to be able to allocate a vector across cpus
> that are not online to properly handle combinations like lowest
> priority interrupt delivery and cpu_hotplug.  Not that we can do
> that today but the infrastructure shouldn't prevent it.
>
> So this patch updates the places where we touch per cpu data
> to only touch online cpus, it makes cpu vector allocation
> an atomic operation with respect to cpu hotplug, and it updates
> the cpu start code to properly initialize vector_irq so we
> don't have inconsistencies.
>
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>

Acked-by: Yinghai Lu <yinghai.lu@xxxxxxx>
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