VirtualBox SF Driver Ejected From The Linux 5.4 Kernel
The VirtualBox Shared Folder (VBOXSF) driver will not be part of the mainline Linux 5.4 kernel. Linus was unhappy that it didn't have the necessary sign-offs plus that it's coming late in the cycle and not appearing to meet quality expectations.
In deleting the VirtualBox shared folder driver he noted:
This went into staging in rc7. It turns out that was a mistake, and apparently it wasn't even supposed to go there at all, but be introduced as a regular filesystem.
We don't try to sneak in whole new filesystems this late in the rc, just delete the whole thing, and it can be re-introduced as a proper patch with proper acks from actual filesystem people instead of some odd late-rc staging back-door.
The Linux 5.5 merge window is opening in the next week or two (depending upon how the rest of the 5.4 cycle plays out) so will likely try to be reintroduced for that next kernel cycle.