smp_rmb
smp_rmb();
smp_rmb();
smp_rmb();
smp_rmb();
smp_rmb();
smp_rmb();
smp_rmb();
smp_rmb(); /* pairs with overwrite protection in process_csb() */
smp_rmb(); /* and complete the seqlock retry */
smp_rmb(); /* serialise with add_active_barriers */
smp_rmb(); /* serialise with add_active_barriers */
smp_rmb(); /* serialise with add_active_barriers */
smp_rmb();
smp_rmb();
#ifndef smp_rmb
smp_rmb();