[PATCH 1/1] nvme-fabrics: Generate uevent on namespace AENs

[Belanger, Martin]

++Vinay Rao, Stuart Hayes.

________________________________________
From: Christoph Hellwig <hch at lst.de>
Sent: Thursday, April 29, 2021 02:30
To: Martin Belanger
Cc: linux-nvme at lists.infradead.org; kbusch at kernel.org; axboe at fb.com; hch at lst.de; sagi at grimberg.me; Belanger, Martin; Belanger, Martin
Subject: Re: [PATCH 1/1] nvme-fabrics: Generate uevent on namespace AENs


[EXTERNAL EMAIL]

On Wed, Apr 28, 2021 at 04:18:25PM -0400, Martin Belanger wrote:
> From: Martin Belanger <martin.belanger at dell.com>
>
> Generate uevent on NVMe Async Event Notifications for NS_CHANGED and ANA. Today
> the uevent handler is not capturing on NVME_AER_NOTICE_NS_CHANGED
> (Namespace Changed) and NVME_AER_NOTICE_ANA (Asymmetric Namespace Access).

So the problem with these events is that they are only really useful
to then issue the Get Log Page command for the corresponding log page.
But reading the log page will clear the contents of the log page.  That
is if userspace races to do this first it will completely mess up the
funtionality in the kernel.

This is a bit of an unfortunately design issue in the NVMe protocol.

Maybe you can explain you use case in a little more detail so that we
can figure out what we can do instead.