Re: [KVM PATCH v4 1/2] eventfd: export eventfd interfaces for module use

Gregory Haskins
2009-05-05T02:17:39Z

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Al Viro wrote:
> On Mon, May 04, 2009 at 01:57:45PM -0400, Gregory Haskins wrote:
>
>> @@ -56,6 +57,7 @@ int eventfd_signal(struct file *file, int n)
>>
>> return n;
>> }
>> +EXPORT_SYMBOL_GPL(eventfd_signal);
>>
>
> perhaps, but...
>
>
>> @@ -197,6 +199,7 @@ struct file *eventfd_fget(int fd)
>>
>> return file;
>> }
>> +EXPORT_SYMBOL_GPL(eventfd_fget);
>>
>
> this one looks very odd. Could you show legitimate users?
>
Hi Al,

I plan on using this in a similar way as the AIO io_submit function does
today for the next version of the virtual-bus patches. That is,
userspace allocates an eventfd (in this case, via kvm_irqfd() and the
kernel side code you have been reviewing) and subsequently submits the
fd to a unique virtual-bus instance in the kernel via an ioctl(). This
will ultimately associate the vbus instance dynamically with the kvm
instance in a loosely coupled relationship. Vbus may be compiled as a
module, thus the export.

-Greg

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