Re: [PATCH] usb: musb: mark PM functions as __maybe_unused

From: Arnd Bergmann
Date: Mon Nov 28 2016 - 05:55:27 EST


On Monday, November 28, 2016 11:51:37 AM CET Geert Uytterhoeven wrote:
> On Tue, Nov 22, 2016 at 3:30 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > Building without CONFIG_PM causes a harmless warning:
> >
> > drivers/usb/musb/musb_core.c:2041:12: error: âmusb_run_resume_workâ defined but not used [-Werror=unused-function]
> >
> > Removing the #ifdef around the PM code and instead marking the suspend/resume
> > functions as __maybe_unused will do the right thing without warning.
> >
> > Fixes: ea2f35c01d5e ("usb: musb: Fix sleeping function called from invalid context for hdrc glue")
> > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
>
> linux-m68k-allmodconfig$ bloat-o-meter drivers/usb/musb/musb_core.o{.orig,}
> add/remove: 8/0 grow/shrink: 0/0 up/down: 2344/0 (2344)
> function old new delta
> musb_restore_context - 892 +892
> musb_save_context - 690 +690
> musb_run_resume_work - 190 +190
> musb_resume - 182 +182
> musb_runtime_resume - 148 +148
> musb_suspend - 114 +114
> musb_dev_pm_ops - 92 +92
> musb_runtime_suspend - 36 +36
> Total: Before=13091, After=15435, chg +17.91%

Well, in allmodconfig, you have CONFIG_PM enabled, so this is not
dead code but actually does what was intended (though possibly
not written as efficiently as it could have been).

In a configuration without CONFIG_PM, there should ideally be
no added code.

Arnd