locking/lockdep: Update two outdated comments

synchronize_sched() has been removed recently. Update the comments that
refer to synchronize_sched().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Fixes: 51959d8 ("lockdep: Replace synchronize_sched() with synchronize_rcu()") # v5.0-rc1
Link: https://lkml.kernel.org/r/20190214230058.196511-11-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/locking/lockdep.c

@@ -4188,9 +4188,9 @@ static void __lockdep_free_key_range(void *start, unsigned long size)
  * Used in module.c to remove lock classes from memory that is going to be
  * freed; and possibly re-used by other modules.
  *
- * We will have had one sync_sched() before getting here, so we're guaranteed
- * nobody will look up these exact classes -- they're properly dead but still
- * allocated.
+ * We will have had one synchronize_rcu() before getting here, so we're
+ * guaranteed nobody will look up these exact classes -- they're properly dead
+ * but still allocated.
  */
 void lockdep_free_key_range(void *start, unsigned long size)
 {
@@ -4209,8 +4209,6 @@ void lockdep_free_key_range(void *start, unsigned long size)
 	/*
 	 * Wait for any possible iterators from look_up_lock_class() to pass
 	 * before continuing to free the memory they refer to.
-	 *
-	 * sync_sched() is sufficient because the read-side is IRQ disable.
 	 */
 	synchronize_rcu();