[PATCH v4 10/11] nvme: Atomic write support

[Christoph Hellwig]

Thanks for writing a good commit message!

> NVMe namespaces may define an atomic boundary, whereby no atomic guarantees
> are provided for a write which straddles this per-lba space boundary. The
> block layer merging policy is such that no merges may occur in which the
> resultant request would straddle such a boundary.
> 
> Unlike SCSI, NVMe specifies no granularity or alignment rules.

Well, the boundary really is sort of a granularity and alignment,
isn't it?