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>

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index f2ea678c269f5aeb445be04908746757716ba6bd..161301fff97d05f00d53c8e95d211bcf26d1c1a0 100644 (file)
--- 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);