Reminder: we maintain a kernel feature wishlist here as part of the uapi group:
https://github.com/uapi-group/kernel-features
I just added a bunch of new entries to it (at the bottom). If you are looking for something to hack on (and have some kernel expertise, or would like to acquire it), would be more than excellent to work on those!
@brokenix I have no idea of riscv, no of vmsplice, nor of dcas. Sorry. Simply the wrong person to comment on this.
@pid_eins "Ability to link an O_TMPFILE file into a directory while replacing an existing file" I had patches for this ages ago: https://lore.kernel.org/all/cover.1580251857.git.osandov__34029.5823452593$1580288332$gmane$org@fb.com/ My first few attempts died out waiting for Viro, and the last try got everyone worked up about the meaning of atomicity: https://lore.kernel.org/all/CAOQ4uxit0KYiShpEXt8b8SvN8bWWp3Ky929b+UWNDozTCUeTxg@mail.gmail.com/ Maybe now with @brauner maintaining the VFS, another attempt would have better luck...