want mechanism to override physical block size of NVMe devices
All the NVMe devices that I had worked with so far use a 512 byte block size by default. Some of them also report other supported block sizes and the driver uses that to report the best performing block size as physical block size to blkdev.
Some SSDs such as the Samsung SM941 and SM951 report no other block sizes than 512 bytes. Apparently some users tried unsuccessfully to use the sd.conf workaround on nvme to fix this, so I think a similar mechanism for nvme would be useful to have.
This will introduce a min-phys-block-size property to nvme.conf which can be set to any power of 2. The maximum of this value and the best physical block size reported will be used as physical block size by the driver.