Merge tag 'riscv-for-linus-4.16-rc4_smp_mb' of git://

Pull RISC-V fix from Palmer Dabbelt:
 "This week we have a single fix: replacing smp_mb() with __smp_mb().

  We were the only architecture with smp_mb() and it appears to just be
  clearly wrong, so I think this is a pretty safe patch for an RC"

* tag 'riscv-for-linus-4.16-rc4_smp_mb' of git://
  riscv/barrier: Define __smp_{mb,rmb,wmb}