rcu: Remove CONFIG_PREEMPT_RCU

Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no
further need for CONFIG_PREEMPT_RCU.  Remove it, along with
whatever subtle bugs it may (or may not) contain.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: <125097461396-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 19 deletions

diff --git a/init/Kconfig b/init/Kconfig
index f88da2d1c1fb..8e8b76d8a272 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -324,17 +324,6 @@ config TREE_RCU
           thousands of CPUs.  It also scales down nicely to
           smaller systems.
 
-config PREEMPT_RCU
-        bool "Preemptible RCU"
-        depends on PREEMPT
-        help
-          This option reduces the latency of the kernel by making certain
-          RCU sections preemptible. Normally RCU code is non-preemptible, if
-          this option is selected then read-only RCU sections become
-          preemptible. This helps latency, but may expose bugs due to
-          now-naive assumptions about each RCU read-side critical section
-          remaining on a given CPU through its execution.
-
 config TREE_PREEMPT_RCU
         bool "Preemptable tree-based hierarchical RCU"
         depends on PREEMPT
@@ -348,7 +337,7 @@ endchoice
 
 config RCU_TRACE
         bool "Enable tracing for RCU"
-        depends on TREE_RCU || PREEMPT_RCU || TREE_PREEMPT_RCU
+        depends on TREE_RCU || TREE_PREEMPT_RCU
         help
           This option provides tracing in RCU which presents stats
           in debugfs for debugging RCU implementation.
@@ -395,13 +384,6 @@ config TREE_RCU_TRACE
           TREE_PREEMPT_RCU implementations, permitting Makefile to
           trivially select kernel/rcutree_trace.c.
 
-config PREEMPT_RCU_TRACE
-        def_bool RCU_TRACE && PREEMPT_RCU
-        select DEBUG_FS
-        help
-          This option provides tracing for the PREEMPT_RCU implementation,
-          permitting Makefile to trivially select kernel/rcupreempt_trace.c.
-
 endmenu # "RCU Subsystem"
 
 config IKCONFIG