Re: [PATCH v4 06/10] evtchn: slightly defer lock acquire where possible

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 05/01/2021 13:11, Jan Beulich wrote:
> port_is_valid() and evtchn_from_port() are fine to use without holding
> any locks.
Per my remark in patch #1, currently, this only holds as long as we are 
checking the port for the current domain.
If it were a different domain, then the risk a risk that port_is_valid() 
may return valid and then invalid.
AFAICT, evtchn_close() may be called with d != current. So there is some 
racyness in the code as well.
Therefore, I will defer my ack until we agree on whether port_is_valid() 
can be used locklessly when current != domain.
Cheers,