2 files changed, 33 insertions, 8 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 950ba26f7233..bd125a795374 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -21,6 +21,13 @@ config CONSTRUCTORS
         depends on !UML
         default y
 
+config HAVE_IRQ_WORK
+        bool
+
+config IRQ_WORK
+        bool
+        depends on HAVE_IRQ_WORK
+
 menu "General setup"
 
 config EXPERIMENTAL
@@ -64,7 +71,7 @@ config BROKEN_ON_SMP
 
 config LOCK_KERNEL
         bool
-        depends on SMP || PREEMPT
+        depends on (SMP || PREEMPT) && BKL
         default y
 
 config INIT_ENV_ARG_LIMIT
@@ -332,6 +339,8 @@ config AUDIT_TREE
         depends on AUDITSYSCALL
         select FSNOTIFY
 
+source "kernel/irq/Kconfig"
+
 menu "RCU Subsystem"
 
 choice
@@ -340,6 +349,7 @@ choice
 
 config TREE_RCU
         bool "Tree-based hierarchical RCU"
+        depends on !PREEMPT && SMP
         help
           This option selects the RCU implementation that is
           designed for very large SMP system with hundreds or
@@ -347,7 +357,7 @@ config TREE_RCU
           smaller systems.
 
 config TREE_PREEMPT_RCU
-        bool "Preemptable tree-based hierarchical RCU"
+        bool "Preemptible tree-based hierarchical RCU"
         depends on PREEMPT
         help
           This option selects the RCU implementation that is
@@ -365,8 +375,22 @@ config TINY_RCU
           is not required.  This option greatly reduces the
           memory footprint of RCU.
 
+config TINY_PREEMPT_RCU
+        bool "Preemptible UP-only small-memory-footprint RCU"
+        depends on !SMP && PREEMPT
+        help
+          This option selects the RCU implementation that is designed
+          for real-time UP systems.  This option greatly reduces the
+          memory footprint of RCU.
+
 endchoice
 
+config PREEMPT_RCU
+        def_bool ( TREE_PREEMPT_RCU || TINY_PREEMPT_RCU )
+        help
+          This option enables preemptible-RCU code that is common between
+          the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
+
 config RCU_TRACE
         bool "Enable tracing for RCU"
         depends on TREE_RCU || TREE_PREEMPT_RCU
@@ -387,9 +411,12 @@ config RCU_FANOUT
         help
           This option controls the fanout of hierarchical implementations
           of RCU, allowing RCU to work efficiently on machines with
-          large numbers of CPUs.  This value must be at least the cube
-          root of NR_CPUS, which allows NR_CPUS up to 32,768 for 32-bit
-          systems and up to 262,144 for 64-bit systems.
+          large numbers of CPUs.  This value must be at least the fourth
+          root of NR_CPUS, which allows NR_CPUS to be insanely large.
+          The default value of RCU_FANOUT should be used for production
+          systems, but if you are stress-testing the RCU implementation
+          itself, small RCU_FANOUT values allow you to test large-system
+          code paths on small(er) systems.
 
           Select a specific number if testing RCU itself.
           Take the default if unsure.
@@ -990,6 +1017,7 @@ config PERF_EVENTS
         default y if (PROFILING || PERF_COUNTERS)
         depends on HAVE_PERF_EVENTS
         select ANON_INODES
+        select IRQ_WORK
         help
           Enable kernel support for various performance events provided
           by software and hardware.
diff --git a/init/main.c b/init/main.c
index 94ab488039aa..e59af24a0b7c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -424,7 +424,6 @@ static void __init setup_command_line(char *command_line)
 static __initdata DECLARE_COMPLETION(kthreadd_done);
 
 static noinline void __init_refok rest_init(void)
-        __releases(kernel_lock)
 {
         int pid;
 
@@ -556,7 +555,6 @@ asmlinkage void __init start_kernel(void)
 
         local_irq_disable();
         early_boot_irqs_off();
-        early_init_irq_lock_class();
 
 /*
  * Interrupts are still disabled. Do necessary setups, then
@@ -819,7 +817,6 @@ static void run_init_process(const char *init_filename)
  * makes it inline to init() and it becomes part of init.text section
  */
 static noinline int init_post(void)
-        __releases(kernel_lock)
 {
         /* need to finish all async __init code before freeing the memory */
         async_synchronize_full();