tracing: Replace synchronize_sched() and call_rcu_sched()

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().  Similarly, call_rcu_sched() can be
replaced by call_rcu().  This commit therefore makes these changes.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <linux-kernel@vger.kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 12 insertions, 12 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f536f601bd46..5b4f73e4fd56 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -173,7 +173,7 @@ static void ftrace_sync(struct work_struct *work)
 {
         /*
          * 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.
          *
          * Yes, function tracing is rude.
@@ -934,7 +934,7 @@ ftrace_profile_write(struct file *filp, const char __user *ubuf,
                         ftrace_profile_enabled = 0;
                         /*
                          * unregister_ftrace_profiler calls stop_machine
-                         * so this acts like an synchronize_sched.
+                         * so this acts like an synchronize_rcu.
                          */
                         unregister_ftrace_profiler();
                 }
@@ -1086,7 +1086,7 @@ struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
 
         /*
          * Some of the ops may be dynamically allocated,
-         * they are freed after a synchronize_sched().
+         * they are freed after a synchronize_rcu().
          */
         preempt_disable_notrace();
 
@@ -1286,7 +1286,7 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
 {
         if (!hash || hash == EMPTY_HASH)
                 return;
-        call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
+        call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
 }
 
 void ftrace_free_filter(struct ftrace_ops *ops)
@@ -1501,7 +1501,7 @@ static bool hash_contains_ip(unsigned long ip,
  * the ip is not in the ops->notrace_hash.
  *
  * This needs to be called with preemption disabled as
- * the hashes are freed with call_rcu_sched().
+ * the hashes are freed with call_rcu().
  */
 static int
 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
@@ -4496,7 +4496,7 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
         if (ftrace_enabled && !ftrace_hash_empty(hash))
                 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
                                        &old_hash_ops);
-        synchronize_sched();
+        synchronize_rcu();
 
         hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
                 hlist_del(&entry->hlist);
@@ -5314,7 +5314,7 @@ ftrace_graph_release(struct inode *inode, struct file *file)
                 mutex_unlock(&graph_lock);
 
                 /* Wait till all users are no longer using the old hash */
-                synchronize_sched();
+                synchronize_rcu();
 
                 free_ftrace_hash(old_hash);
         }
@@ -5707,7 +5707,7 @@ void ftrace_release_mod(struct module *mod)
         list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
                 if (mod_map->mod == mod) {
                         list_del_rcu(&mod_map->list);
-                        call_rcu_sched(&mod_map->rcu, ftrace_free_mod_map);
+                        call_rcu(&mod_map->rcu, ftrace_free_mod_map);
                         break;
                 }
         }
@@ -5927,7 +5927,7 @@ ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
         struct ftrace_mod_map *mod_map;
         const char *ret = NULL;
 
-        /* mod_map is freed via call_rcu_sched() */
+        /* mod_map is freed via call_rcu() */
         preempt_disable();
         list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
                 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
@@ -6262,7 +6262,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 
         /*
          * Some of the ops may be dynamically allocated,
-         * they must be freed after a synchronize_sched().
+         * they must be freed after a synchronize_rcu().
          */
         preempt_disable_notrace();
 
@@ -6433,7 +6433,7 @@ static void clear_ftrace_pids(struct trace_array *tr)
         rcu_assign_pointer(tr->function_pids, NULL);
 
         /* Wait till all users are no longer using pid filtering */
-        synchronize_sched();
+        synchronize_rcu();
 
         trace_free_pid_list(pid_list);
 }
@@ -6580,7 +6580,7 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
         rcu_assign_pointer(tr->function_pids, pid_list);
 
         if (filtered_pids) {
-                synchronize_sched();
+                synchronize_rcu();
                 trace_free_pid_list(filtered_pids);
         } else if (pid_list) {
                 /* Register a probe to set whether to ignore the tracing of a task */