On 02/26/2018 02:35 AM, Sebastian Andrzej Siewior wrote:
On 2018-02-25 21:04:27 [-0500], Hook, Gary wrote:
On 2/23/2018 5:33 PM, Sebastian Andrzej Siewior wrote:
I don't why we need take a single write lock and disable interrupts
while setting up debugfs. This is what what happens when we try anyway:
There is more than one CCP on some processors. The lock is intended to
serialize attempts to initialize the new directory, but a R/W lock isn't
required.
And they are probed in parallel? Any you need disable interrupts while
creating the debugfs folder? A mutex isn't enough?
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?
I think a mutex would be just fine; I got this wrong, clearly. Let me
work up a patch using a mutex.
Gary
