The “scatterlist” is a core-kernel data structure used to describe DMA I/O
operations from the point of view of both the CPU and the peripheral
device. Over the years, the shortcomings of scatterlists have become more
apparent, but there has not been a viable replacement on the horizon.
During a memory-management session at the 2023 Linux Storage, Filesystem, Memory-Management
and BPF Summit, Jason Gunthorpe described a possible alternative, known
alternatively as “phyr”, “physr”, or “rlist”, that might improve on
scatterlists for at least some use cases.

Source: LWN.net – [$] Phyr: a potential scatterlist replacement