Commit 9db1ff0a authored Jun 25, 2019 by Yonghong Song Committed by Daniel Borkmann Jun 26, 2019

bpf: fix compiler warning with CONFIG_MODULES=n



With CONFIG_MODULES=n, the following compiler warning occurs:
  /data/users/yhs/work/net-next/kernel/trace/bpf_trace.c:605:13: warning:
      ‘do_bpf_send_signal’ defined but not used [-Wunused-function]
  static void do_bpf_send_signal(struct irq_work *entry)

The __init function send_signal_irq_work_init(), which calls
do_bpf_send_signal(), is defined under CONFIG_MODULES. Hence,
when CONFIG_MODULES=n, nobody calls static function do_bpf_send_signal(),
hence the warning.

The init function send_signal_irq_work_init() should work without
CONFIG_MODULES. Moving it out of CONFIG_MODULES
code section fixed the compiler warning, and also make bpf_send_signal()
helper work without CONFIG_MODULES.

Fixes: 8b401f9e ("bpf: implement bpf_send_signal() helper")
Reported-By: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 6bcc617f

kernel/trace/bpf_trace.c

+14 −13

Original line number	Diff line number	Diff line
		@@ -1431,6 +1431,20 @@ int bpf_get_perf_event_info(const struct perf_event event, u32 prog_id,
		return err;
		}

		static int __init send_signal_irq_work_init(void)
		{
		int cpu;
		struct send_signal_irq_work *work;

		for_each_possible_cpu(cpu) {
		work = per_cpu_ptr(&send_signal_work, cpu);
		init_irq_work(&work->irq_work, do_bpf_send_signal);
		}
		return 0;
		}

		subsys_initcall(send_signal_irq_work_init);

		#ifdef CONFIG_MODULES
		static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
		void *module)
		@@ -1478,18 +1492,5 @@ static int __init bpf_event_init(void)
		return 0;
		}

		static int __init send_signal_irq_work_init(void)
		{
		int cpu;
		struct send_signal_irq_work *work;

		for_each_possible_cpu(cpu) {
		work = per_cpu_ptr(&send_signal_work, cpu);
		init_irq_work(&work->irq_work, do_bpf_send_signal);
		}
		return 0;
		}

		fs_initcall(bpf_event_init);
		subsys_initcall(send_signal_irq_work_init);
		#endif /* CONFIG_MODULES */

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