tracepoint: Do not waste memory on mods with no tracepoints

commit 7dec935a3aa04412cba2cebe1524ae0d34a30c24 upstream.

No reason to allocate tp_module structures for modules that have no
tracepoints. This just wastes memory.

Fixes: b75ef8b44b1c "Tracepoint: Dissociate from module mutex"
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 031cc56..63630ae 100644 (file)
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -641,6 +641,9 @@ static int tracepoint_module_coming(struct module *mod)
        struct tp_module *tp_mod, *iter;
        int ret = 0;
 
+       if (!mod->num_tracepoints)
+               return 0;
+
        /*
         * We skip modules that taint the kernel, especially those with different
         * module headers (for forced load), to make sure we don't cause a crash.
@@ -684,6 +687,9 @@ static int tracepoint_module_going(struct module *mod)
 {
        struct tp_module *pos;
 
+       if (!mod->num_tracepoints)
+               return 0;
+
        mutex_lock(&tracepoints_mutex);
        tracepoint_update_probe_range(mod->tracepoints_ptrs,
                mod->tracepoints_ptrs + mod->num_tracepoints);