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>

1 files changed, 3 insertions, 0 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