On Mon, Jan 23, 2023 at 02:57:18PM +0200, Israel Rukshin wrote:

quoted

- what happens with multipathing? when if not all devices are
capable. SW fallback?

SW fallback happens every time the device doesn't support the specific 
crypto request (which include data-unit-size, mode and dun_bytes).
So with multipathing, one path uses the HW crypto offload and the other one 
uses the SW fallback.

That's a big no-go.  The blk-crypto-fallback code is just a toy example
and not actually safe to use in prodution.  Most importantly it just
kmallocs a bio clone and pages for it without any mempool that guarantees
forward progress.