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

[Chaitanya Kulkarni]

On 4/29/21 10:09, Belanger, Martin wrote:
> ++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.

>From the patch that I sent on the same topic to enforce a particular
behavior
either way, I remember that we've decided not to change the kernel code
for usespace.