doc: Update removal of RCU-bh/sched update machinery

The RCU-bh update API is now defined in terms of that of RCU-bh and
RCU-sched, so this commit updates the documentation accordingly.

In addition, although RCU-sched persists in !PREEMPT kernels, in
the PREEMPT case its update API is now defined in terms of that of
RCU-preempt, so this commit also updates the documentation accordingly.

While in the area, this commit removes the documentation for the
now-obsolete synchronize_rcu_mult() and clarifies the Tasks RCU
documentation.

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

1 files changed, 3 insertions, 4 deletions

diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
index 7394f034be65..ffd612bfa436 100644
--- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
+++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
@@ -12,10 +12,9 @@ high efficiency and minimal disturbance, expedited grace periods accept
 lower efficiency and significant disturbance to attain shorter latencies.
 
 <p>
-There are three flavors of RCU (RCU-bh, RCU-preempt, and RCU-sched),
-but only two flavors of expedited grace periods because the RCU-bh
-expedited grace period maps onto the RCU-sched expedited grace period.
-Each of the remaining two implementations is covered in its own section.
+There are two flavors of RCU (RCU-preempt and RCU-sched), with an earlier
+third RCU-bh flavor having been implemented in terms of the other two.
+Each of the two implementations is covered in its own section.
 
 <ol>
 <li>	<a href="#Expedited Grace Period Design">