[Bridge] get rid of the address_space override in setsockopt

[Alexei Starovoitov]

On Mon, Jul 20, 2020 at 02:47:13PM +0200, Christoph Hellwig wrote:
> Hi Dave,
> 
> setsockopt is the last place in architecture-independ code that still
> uses set_fs to force the uaccess routines to operate on kernel pointers.
> 
> This series adds a new sockptr_t type that can contained either a kernel
> or user pointer, and which has accessors that do the right thing, and
> then uses it for setsockopt, starting by refactoring some low-level
> helpers and moving them over to it before finally doing the main
> setsockopt method.
> 
> Note that I could not get the eBPF selftests to work, so this has been
> tested with a testing patch that always copies the data first and passes
> a kernel pointer.  This is something that works for most common sockopts
> (and is something that the ePBF support relies on), but unfortunately
> in various corner cases we either don't use the passed in length, or in
> one case actually copy data back from setsockopt, so we unfortunately
> can't just always do the copy in the highlevel code, which would have
> been much nicer.

could you rebase on bpf-next tree and we can route it this way then?
we'll also test the whole thing before applying.

sounds like v2 is needed anyway to address Eric's addr space concern?