jump_label: Move CPU hotplug locking

As we're about to rework the locking, let's move the taking and
release of the CPU hotplug lock to locations that will make its
reworking completely obvious.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170801080257.5056-2-marc.zyngier@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index f2ea678c269f..161301fff97d 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -83,6 +83,7 @@ void static_key_slow_inc(struct static_key *key)
 {
         int v, v1;
 
+        cpus_read_lock();
         STATIC_KEY_CHECK_USE();
 
         /*
@@ -99,11 +100,12 @@ void static_key_slow_inc(struct static_key *key)
          */
         for (v = atomic_read(&key->enabled); v > 0; v = v1) {
                 v1 = atomic_cmpxchg(&key->enabled, v, v + 1);
-                if (likely(v1 == v))
+                if (likely(v1 == v)) {
+                        cpus_read_unlock();
                         return;
+                }
         }
 
-        cpus_read_lock();
         jump_label_lock();
         if (atomic_read(&key->enabled) == 0) {
                 atomic_set(&key->enabled, -1);