RE: [RFC PATCH 2/3] x86, MCE: Avoid potential deadlock in MCE context

["Luck, Tony" <tony.luck@intel.com>]

> And drop all the homegrown other stuff like mce_ring and all?

mce_ring should be easy ... the "mce" structure has the address
from which we can easily get the pfn to pass into the action-optional
recovery path.  Only thing missing is a direct indication that this mce
does contain an AO error that needs to be processed. We could
re-invoke mce_severity() to figure it out again - or just add a flag
somewhere.

Not so sure about mce_info. This one passes from the
MCE context to the same task when we catch it in process
context (set_thread_flag(MCE_NOTIFY)).  Back when I was pushing
this code it, I really wanted to just add a field to the thread_info
structure to hold the address ... because this really is some
information that belongs to the thread. But I was unable to
convince people back then.  We must be able to find the
page frame when we arrive in mce_notify_process(). So we
can't stash it in some limited size pool of "mce" structures that
might decide to just drop this one.

-Tony