rcu: Define RCU-bh update API in terms of RCU

Now that the main RCU API knows about softirq disabling and softirq's
quiescent states, the RCU-bh update code can be dispensed with.
This commit therefore removes the RCU-bh update-side implementation and
defines RCU-bh's update-side API in terms of that of either RCU-preempt or
RCU-sched, depending on the setting of the CONFIG_PREEMPT Kconfig option.

In kernels built with CONFIG_RCU_NOCB_CPU=y this has the knock-on effect
of reducing by one the number of rcuo kthreads per CPU.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index ebd69694144a..7a0720a20003 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -301,7 +301,6 @@ restart:
 		pending >>= softirq_bit;
 	}
 
-	rcu_bh_qs();
 	if (__this_cpu_read(ksoftirqd) == current)
 		rcu_softirq_qs();
 	local_irq_disable();