What should we do about the nvme atomics mess?

[John Garry]

On 10/07/2025 06:07, Nilay Shroff wrote:
>> Considering multi-controller subsystems, some controllers might have
>> namespaces with only 512b formats attached, and other controllers might
>> have some 4k mixed in, so then they can't all consistently report the
>> desired AWUPF value. They'd have to just scale AWUPF based on the
>> largest sector size supported. Which I guess is what the current wording
>> is guiding toward, but that just suggests host drivers disregard the
>> value and use NAWUPF instead. So still option III.
> Yes, I agree — option III seems to be the best possible way forward.
> However, does this mean we would disregard atomic write support for any
> multi-controller NVMe vendor that consistently reports a valid AWUPF value
> across all controllers and namespace formats, but sets NAWUPF to zero?

Hi Nilay,

Does the drive which you are using report NAWUPF as zero (as hinted)?

If so, have you tried the following 
https://lore.kernel.org/linux-nvme/20250820150220.1923826-1-john.g.garry@oracle.com/

We were considering changing the NVMe driver to not use AWUPF at all...

Thanks,
John