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

[Christoph Hellwig]

On Tue, Oct 18, 2022 at 08:12:59PM +0000, Clay Mayers wrote:
> 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.