livepatch: Replace synchronize_sched() with synchronize_rcu()

Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can be
replaced by synchronize_rcu().  This commit therefore makes this change,
even though it is but a comment.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index 82d584225dc68e2b240a96ef5e1dd19917974fb0..7702cb4064fce82e6abc2f5b539bb61a271b00d3 100644 (file)
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -61,7 +61,7 @@ static void notrace klp_ftrace_handler(unsigned long ip,
        ops = container_of(fops, struct klp_ops, fops);
 
        /*
-        * A variant of synchronize_sched() is used to allow patching functions
+        * A variant of synchronize_rcu() is used to allow patching functions
         * where RCU is not watching, see klp_synchronize_transition().
         */
        preempt_disable_notrace();
@@ -72,7 +72,7 @@ static void notrace klp_ftrace_handler(unsigned long ip,
        /*
         * func should never be NULL because preemption should be disabled here
         * and unregister_ftrace_function() does the equivalent of a
-        * synchronize_sched() before the func_stack removal.
+        * synchronize_rcu() before the func_stack removal.
         */
        if (WARN_ON_ONCE(!func))
                goto unlock;

diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 5bc349805e033fbfdbf5fb811026044695289d0b..304d5eb8a98cbfe2068941117476f04a80e7b7fc 100644 (file)
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -52,7 +52,7 @@ static DECLARE_DELAYED_WORK(klp_transition_work, klp_transition_work_fn);
 
 /*
  * This function is just a stub to implement a hard force
- * of synchronize_sched(). This requires synchronizing
+ * of synchronize_rcu(). This requires synchronizing
  * tasks even in userspace and idle.
  */
 static void klp_sync(struct work_struct *work)
@@ -175,7 +175,7 @@ void klp_cancel_transition(void)
 void klp_update_patch_state(struct task_struct *task)
 {
        /*
-        * A variant of synchronize_sched() is used to allow patching functions
+        * A variant of synchronize_rcu() is used to allow patching functions
         * where RCU is not watching, see klp_synchronize_transition().
         */
        preempt_disable_notrace();