Can a driver->probe be called for two devices at the same time (WAS: Re: [PATCH] crypto/ccp: don't disable interrupts while setting up debugfs)

Sebastian Andrzej Siewior
2018-02-27T17:33:14Z

On 2018-02-27 11:08:56 [-0600], Gary R Hook wrote:
> That issue remains unclear to me: Are probes of PCI devices guaranteed to be
> serialized? Observations on my CCPs says that they occur in order, but I
> don't know for certain that serialization is guaranteed.
>
> Is there a definitive statement on this somewhere that I just don't know
> about?

So the question if a driver can probe two devices simultaneously. I'm
not sure. We have PROBE_PREFER_ASYNCHRONOUS which defers the probe to
worker. However I have no idea if two of those worker can run at the
same time.

> I think a mutex would be just fine; I got this wrong, clearly. Let me work
> up a patch using a mutex.

I've sent one. Why not just ack it and be done with it?

> Gary

Sebastian