[PATCH V2 1/2] nvme: Include AEN CQE.DW1 in NVME_AEN uevents

[Sagi Grimberg]

>> What happens today is a warning is logged and the log page is left
>> unread.  The patch closes that gap allowing ZDC AENs to be enable
>> and handled in user space for things like RocksDB's ZenFS.  Kernel
>> clients will also need a way to handle them, but can't that be a
>> different patch series?
> 
> The problem is how the NVMe AENs work - the are raised and then the
> AEN command completion is delivered and they are cleared by reading
> the log page.  But if we deliver them to userspace, we lose the pending
> state of the AEN for the kernel.  Right now that is not an issue,
> but we lose all chance of ever making use of that information in
> the kernel.  So maybe the answer is to handle the AEN in the kernel,
> read the changed zones log in the kernel, and then send an uevent
> for all changes zones to userspace.

That is what I was thinking... I feel we had this discussion before
on a different AEN (maybe it was something that wanted to get ANA
info to userspace)...