23 files changed, 34 insertions, 1 deletions

diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index 466bd299b1a8..3afee5f40f4f 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -23,6 +23,7 @@ config KVM
         select HAVE_KVM_CPU_RELAX_INTERCEPT
         select KVM_MMIO
         select KVM_ARM_HOST
+        select SRCU
         depends on ARM_VIRT_EXT && ARM_LPAE
         ---help---
           Support hosting virtualized guest machines. You will also
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 8ba85e9ea388..b334084d3675 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -26,6 +26,7 @@ config KVM
         select KVM_ARM_HOST
         select KVM_ARM_VGIC
         select KVM_ARM_TIMER
+        select SRCU
         ---help---
           Support hosting virtualized guest machines.
 
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 30e334e823bd..2ae12825529f 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -20,6 +20,7 @@ config KVM
         select PREEMPT_NOTIFIERS
         select ANON_INODES
         select KVM_MMIO
+        select SRCU
         ---help---
           Support for hosting Guest kernels.
           Currently supported on MIPS32 processors.
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index f5769f19ae25..11850f310fb4 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -21,6 +21,7 @@ config KVM
         select PREEMPT_NOTIFIERS
         select ANON_INODES
         select HAVE_KVM_EVENTFD
+        select SRCU
 
 config KVM_BOOK3S_HANDLER
         bool
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 646db9c467d1..5fce52cf0e57 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -28,6 +28,7 @@ config KVM
         select HAVE_KVM_IRQCHIP
         select HAVE_KVM_IRQFD
         select HAVE_KVM_IRQ_ROUTING
+        select SRCU
         ---help---
           Support hosting paravirtualized guest machines using the SIE
           virtualization capability on the mainframe. This should work
diff --git a/arch/tile/kvm/Kconfig b/arch/tile/kvm/Kconfig
index 2298cb1daff7..1e968f7550dc 100644
--- a/arch/tile/kvm/Kconfig
+++ b/arch/tile/kvm/Kconfig
@@ -21,6 +21,7 @@ config KVM
         depends on HAVE_KVM && MODULES
         select PREEMPT_NOTIFIERS
         select ANON_INODES
+        select SRCU
         ---help---
           Support hosting paravirtualized guest machines.
 
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ba397bde7948..661269953c1a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -138,6 +138,7 @@ config X86
         select HAVE_ACPI_APEI_NMI if ACPI
         select ACPI_LEGACY_TABLES_LOOKUP if ACPI
         select X86_FEATURE_NAMES if PROC_FS
+        select SRCU
 
 config INSTRUCTION_DECODER
         def_bool y
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index f9d16ff56c6b..7dc7ba577ecd 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -40,6 +40,7 @@ config KVM
         select HAVE_KVM_MSI
         select HAVE_KVM_CPU_RELAX_INTERCEPT
         select KVM_VFIO
+        select SRCU
         ---help---
           Support hosting fully virtualized guest machines using hardware
           virtualization extensions.  You will need a fairly recent
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 3f44f292d066..91f86131bb7a 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -13,6 +13,7 @@ config COMMON_CLK
         bool
         select HAVE_CLK_PREPARE
         select CLKDEV_LOOKUP
+        select SRCU
         ---help---
           The common clock framework is a single definition of struct
           clk, useful across many platforms, as well as an
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 29b2ef5a68b9..a171fef2c2b6 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -2,6 +2,7 @@ menu "CPU Frequency scaling"
 
 config CPU_FREQ
         bool "CPU Frequency scaling"
+        select SRCU
         help
           CPU Frequency scaling allows you to change the clock speed of 
           CPUs on the fly. This is a nice method to save power, because 
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index faf4e70c42e0..3891f6781298 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -1,5 +1,6 @@
 menuconfig PM_DEVFREQ
         bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
+        select SRCU
         help
           A device may have a list of frequencies and voltages available.
           devfreq, a generic DVFS framework can be registered for a device
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 5bdedf6df153..c355a226a024 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -5,6 +5,7 @@
 menuconfig MD
         bool "Multiple devices driver support (RAID and LVM)"
         depends on BLOCK
+        select SRCU
         help
           Support multiple physical spindles through a single logical device.
           Required for RAID and logical volume management.
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index d6607ee9c855..84673ebcf428 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -197,6 +197,7 @@ config NETCONSOLE_DYNAMIC
 
 config NETPOLL
         def_bool NETCONSOLE
+        select SRCU
 
 config NET_POLL_CONTROLLER
         def_bool NETPOLL
diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
index a66768ebc8d1..80e9c18ea64f 100644
--- a/fs/btrfs/Kconfig
+++ b/fs/btrfs/Kconfig
@@ -8,6 +8,7 @@ config BTRFS_FS
         select LZO_DECOMPRESS
         select RAID6_PQ
         select XOR_BLOCKS
+        select SRCU
 
         help
           Btrfs is a general purpose copy-on-write filesystem with extents,
diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig
index 22c629eedd82..2a24249b30af 100644
--- a/fs/notify/Kconfig
+++ b/fs/notify/Kconfig
@@ -1,5 +1,6 @@
 config FSNOTIFY
         def_bool n
+        select SRCU
 
 source "fs/notify/dnotify/Kconfig"
 source "fs/notify/inotify/Kconfig"
diff --git a/fs/quota/Kconfig b/fs/quota/Kconfig
index c51df1dd237e..4a09975aac90 100644
--- a/fs/quota/Kconfig
+++ b/fs/quota/Kconfig
@@ -5,6 +5,7 @@
 config QUOTA
         bool "Quota support"
         select QUOTACTL
+        select SRCU
         help
           If you say Y here, you will be able to set per user limits for disk
           usage (also called disk quotas). Currently, it works for the
diff --git a/init/Kconfig b/init/Kconfig
index 9afb971497f4..f085969ba340 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -501,9 +501,17 @@ config TINY_RCU
 
 endchoice
 
+config SRCU
+        bool
+        help
+          This option selects the sleepable version of RCU. This version
+          permits arbitrary sleeping or blocking within RCU read-side critical
+          sections.
+
 config TASKS_RCU
         bool "Task_based RCU implementation using voluntary context switch"
         default n
+        select SRCU
         help
           This option enables a task-based RCU implementation that uses
           only voluntary context switch (not preemption!), idle, and
@@ -1595,6 +1603,7 @@ config PERF_EVENTS
         depends on HAVE_PERF_EVENTS
         select ANON_INODES
         select IRQ_WORK
+        select SRCU
         help
           Enable kernel support for various performance events provided
           by software and hardware.
diff --git a/kernel/notifier.c b/kernel/notifier.c
index 4803da6eab62..ae9fc7cc360e 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -402,6 +402,7 @@ int raw_notifier_call_chain(struct raw_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(raw_notifier_call_chain);
 
+#ifdef CONFIG_SRCU
 /*
  *      SRCU notifier chain routines.    Registration and unregistration
  *      use a mutex, and call_chain is synchronized by SRCU (no locks).
@@ -528,6 +529,8 @@ void srcu_init_notifier_head(struct srcu_notifier_head *nh)
 }
 EXPORT_SYMBOL_GPL(srcu_init_notifier_head);
 
+#endif /* CONFIG_SRCU */
+
 static ATOMIC_NOTIFIER_HEAD(die_chain);
 
 int notrace notify_die(enum die_val val, const char *str,
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 48b28d387c7f..7e01f78f0417 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -251,6 +251,7 @@ config APM_EMULATION
 
 config PM_OPP
         bool
+        select SRCU
         ---help---
           SOCs have a standard set of tuples consisting of frequency and
           voltage pairs that the device will support per voltage domain. This
diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile
index e6fae503d1bc..50a808424b06 100644
--- a/kernel/rcu/Makefile
+++ b/kernel/rcu/Makefile
@@ -1,4 +1,5 @@
-obj-y += update.o srcu.o
+obj-y += update.o
+obj-$(CONFIG_SRCU) += srcu.o
 obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
 obj-$(CONFIG_TREE_RCU) += tree.o
 obj-$(CONFIG_PREEMPT_RCU) += tree.o
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5f2ce616c046..7a9c93e327f2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1215,6 +1215,7 @@ config RCU_TORTURE_TEST
         tristate "torture tests for RCU"
         depends on DEBUG_KERNEL
         select TORTURE_TEST
+        select SRCU
         default n
         help
           This option provides a kernel module that runs torture tests
diff --git a/mm/Kconfig b/mm/Kconfig
index 1d1ae6b078fd..4395b12869c8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -325,6 +325,7 @@ config VIRT_TO_BUS
 
 config MMU_NOTIFIER
         bool
+        select SRCU
 
 config KSM
         bool "Enable KSM for page merging"
diff --git a/security/tomoyo/Kconfig b/security/tomoyo/Kconfig
index 8eb779b9d77f..604e718d68d3 100644
--- a/security/tomoyo/Kconfig
+++ b/security/tomoyo/Kconfig
@@ -5,6 +5,7 @@ config SECURITY_TOMOYO
         select SECURITYFS
         select SECURITY_PATH
         select SECURITY_NETWORK
+        select SRCU
         default n
         help
           This selects TOMOYO Linux, pathname-based access control.