s390/fgraph: Fix to remove ftrace_test_recursion_trylock()

Fix to remove ftrace_test_recursion_trylock() from ftrace_graph_func()
because commit d576aec ("fgraph: Get ftrace recursion lock in
function_graph_enter") has been moved it to function_graph_enter_regs()
already.

Reported-by: Jiri Olsa <[email protected]>
Closes: https://lore.kernel.org/all/Z5O0shrdgeExZ2kF@krava/
Fixes: d576aec ("fgraph: Get ftrace recursion lock in function_graph_enter")
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Tested-by: Jiri Olsa <[email protected]>
Tested-by: Ihor Solodrai <[email protected]>
Reviewed-by: Heiko Carstens <[email protected]>
Link: https://lore.kernel.org/r/173807817692.1854334.2985776940754607459.stgit@devnote2
Signed-off-by: Alexander Gordeev <[email protected]>

Author: mhiramat

arch/s390/kernel/ftrace.c

@@ -266,18 +266,13 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
 		       struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
 	unsigned long *parent = &arch_ftrace_regs(fregs)->regs.gprs[14];
-	int bit;
 
 	if (unlikely(ftrace_graph_is_dead()))
 		return;
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
-	bit = ftrace_test_recursion_trylock(ip, *parent);
-	if (bit < 0)
-		return;
 	if (!function_graph_enter_regs(*parent, ip, 0, parent, fregs))
 		*parent = (unsigned long)&return_to_handler;
-	ftrace_test_recursion_unlock(bit);
 }
 
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */