peek_slot() shouldn't return -EINTR when there's only a single live
iterator, but that's tricky to guarantee - we seem to be returning
-EINTR when we shouldn't, but it's easy enough to handle in the caller.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>