Re: [Xen-devel] [PATCH] assign_irq_vector adjustments

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>> In both i386 and x86-64 Linux, using a static variable (and thus 
>> having the potential of missing synchronization there,
>> as I suspect exists in native Linux) is not needed with the hypercall 
>> approach. In the hypervisor, the patch adds the
>> needed synchronization.
>
>1. Should you not assign to irq_vector[] and vector_irq[] in Xen with 
>the lock held? Otherwise you may double-allocate if two requests are 
>made concurrently to assign for the same irq (unlikely, but...)

Hmm, the vector_irq assignment shouldn't need the lock (which is why I moved 
the unlock up), but you're right, the
IO_APIC_VECTOR() write *and* read should happen with the lock held. I'll update 
that.

>2. Since that'll need a re-send, please also add a Signed-off-by line.

Sure, if you prefer it that way. Should this go into the patch (attachment) or 
the message?

Jan

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