Re: [PATCH] usb: usb-skeleton: Add hint to find __init and __exit

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Oct 23, 2021 at 09:11:37AM +0200, Philipp Hortmann wrote:
> On 10/23/21 8:47 AM, Greg KH wrote:
> > On Sat, Oct 23, 2021 at 07:25:38AM +0200, Philipp Hortmann wrote:
> > > Comment to find __init and __exit.
> > > 
> > > Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
> > > ---
> > >   drivers/usb/usb-skeleton.c | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
> > > index 2dc58766273a..80338a50dcde 100644
> > > --- a/drivers/usb/usb-skeleton.c
> > > +++ b/drivers/usb/usb-skeleton.c
> > > @@ -641,6 +641,7 @@ static struct usb_driver skel_driver = {
> > >   	.supports_autosuspend = 1,
> > >   };
> > > +/* __init and __exit */
> > >   module_usb_driver(skel_driver);
> > 
> > This comment makes no sense, sorry.  __init and __exit are things that
> > the linker uses, why would you need to "find" them?
> > 
> > thanks,
> > 
> > greg k-h
> > 
> 
> When I want to add something to the __init function (debug comment for
> example), how to do this without knowing that it is in module_usb_driver?

The whole point of the module_usb_driver() macro is to keep a developer
from having to write that init_module() and exit_module() functions
entirely.  I think you are getting confused with the __init and __exit
linker hints with the module init/exit functions.  They are totally
different things.

thanks,

greg k-h