percpu_rw_semaphore: introduce CONFIG_PERCPU_RWSEM

Currently only block_dev and uprobes use percpu_rw_semaphore,
add the config option selected by BLOCK || UPROBES.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 1 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 4b31a46fb307..75cdb77fa49d 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -42,6 +42,9 @@ config GENERIC_IO
 config STMP_DEVICE
         bool
 
+config PERCPU_RWSEM
+        boolean
+
 config CRC_CCITT
         tristate "CRC-CCITT functions"
         help
diff --git a/lib/Makefile b/lib/Makefile
index e959c20efb24..5558e35170cd 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -9,7 +9,7 @@ endif
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
          rbtree.o radix-tree.o dump_stack.o timerqueue.o\
-         idr.o int_sqrt.o extable.o percpu-rwsem.o \
+         idr.o int_sqrt.o extable.o \
          sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
          proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
          is_single_threaded.o plist.o decompress.o kobject_uevent.o \
@@ -40,6 +40,7 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
+lib-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
 
 CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
 obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o