[$] Device-initiated I/O

Peer-to-peer DMA (P2PDMA) has been part of
the kernel since the 4.20 release in 2018;
it provides a framework that allows devices to transfer data between themselves
directly, without using system RAM for the transfer. At the 2025 Linux
Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Stephen
Bates led a combined storage, filesystems, and memory-management session on
device-initiated I/O, which is perhaps what P2PDMA is evolving toward. Two
years ago, he led a session on P2PDMA at the
summit; this year's session was a brief update on P2PDMA with a look
at where it may be heading.