[PATCH 5/7] nvme-pci: use a better encoding for small prp pool allocations

[Christoph Hellwig]

On Wed, May 14, 2025 at 07:06:17AM -0600, Keith Busch wrote:
> But if you are trying to merge dozens of requests with metadata into
> one, then yeah, the small pool isn't large enough to accomodate. If you
> want to support that use case, then we can certainly change the driver
> to use the large pool when more than 15 integrity segments are required.

Merge is one use case.  The other is to use non-contigous buffers for file
system PI support, as a single BIO with large folios can get quite huge,
and being able to either use vmalloc or multiple pages would be very
helpful there.