function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACE

When CONFIG_DYNAMIC_FTRACE is not set, the function
fgraph_update_pid_func() doesn't do anything. Currently, most of its logic
is within a "#ifdef CONFIG_DYNAMIC_FTRACE" block, but its variables were
declared outside that, and when DYNAMIC_FTRACE is not set, it produces
unused variable warnings.

Instead, just place it (and the helper function fgraph_pid_func()) within
the #ifdef block and have the header file use a empty stub function for
when DYNAMIC_FTRACE is not defined.

Link: https://lore.kernel.org/linux-trace-kernel/20240607094833.6a787d73@rorschach.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406071806.BRjaC5FF-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2024-06-07 09:48:33 -04:00
parent 2f6b884dfc
commit 4267fda4af
2 changed files with 6 additions and 2 deletions

View File

@ -1138,6 +1138,7 @@ void ftrace_graph_exit_task(struct task_struct *t)
kfree(ret_stack);
}
#ifdef CONFIG_DYNAMIC_FTRACE
static int fgraph_pid_func(struct ftrace_graph_ent *trace,
struct fgraph_ops *gops)
{
@ -1164,7 +1165,6 @@ void fgraph_update_pid_func(void)
if (!(graph_ops.flags & FTRACE_OPS_FL_INITIALIZED))
return;
#ifdef CONFIG_DYNAMIC_FTRACE
list_for_each_entry(op, &graph_ops.subop_list, list) {
if (op->flags & FTRACE_OPS_FL_PID) {
gops = container_of(op, struct fgraph_ops, ops);
@ -1174,8 +1174,8 @@ void fgraph_update_pid_func(void)
static_call_update(fgraph_func, gops->entryfunc);
}
}
#endif
}
#endif
/* Allocate a return stack for each task */
static int start_graph_tracing(void)

View File

@ -52,7 +52,11 @@ static inline int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_o
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern int ftrace_graph_active;
# ifdef CONFIG_DYNAMIC_FTRACE
extern void fgraph_update_pid_func(void);
# else
static inline void fgraph_update_pid_func(void) {}
# endif
#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
# define ftrace_graph_active 0
static inline void fgraph_update_pid_func(void) {}