This was a suggestion that Brian Behlendorf made when reviewing an early
pull request for Linux 3.9 support. This commit was made intentionally
easy to revert should we ever have a reason to reintroduce support for
older kernels.
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>