On Fri, Jul 30, 2010 at 06:08:23PM +0200, Michał Nazarewicz wrote: > On Fri, 30 Jul 2010 17:26:02 +0200, Uwe Kleine-König > <u.kleine-koe...@pengutronix.de> wrote: >> On Fri, Jul 30, 2010 at 05:16:46PM +0200, Michał Nazarewicz wrote: >>> On Fri, 30 Jul 2010 16:49:14 +0200, Uwe Kleine-König >>> <u.kleine-koe...@pengutronix.de> wrote: >>> >>>> This is like usb_gadget_register_driver with the only difference that it >>>> gets the bind function as parameter instead of using driver->bind. This >>>> allows fixing section mismatches like >>>> >>>> WARNING: drivers/usb/gadget/g_printer.o(.data+0xc): Section mismatch in >>>> reference from the variable printer_driver to the function >>>> .init.text:printer_bind() >>>> The variable printer_driver references >>>> the function __init printer_bind() >>>> >>>> by using usb_gadget_probe_driver with driver->bind = NULL. When all >>>> drivers are fixed to use the new function the bind member of struct >>>> usb_gadget_driver can go away. >>>> >>>> Signed-off-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de> >>>> Cc: Michal Nazarewicz <m.nazarew...@samsung.com> >>>> Cc: Greg Kroah-Hartman <gre...@suse.de> > > BTW. Dunno if there is a reason to put me on Cc and Greg will be in > Signed-off-by anyway. > >>>> --- >>>> Hello, >>>> >>>> there is an alternative patch in Greg's tree [1], but IMHO mine is >>>> better as it doesn't need __ref. >>>> >>>> Thoughts? >>> >>> Personally I don't see advantage of this over changing the __init to __ref. >>> Or am I missing something? I see your patch as an unnecessary API change. >>> The way I understand it, __ref was introduced exactly for cases like this >>> one where function is referenced from "normal" data but used only during >>> init. Could you try to clarify for me why you think your solution is >>> better then mine? > >> - Using __ref instead of __init moves all bind functions from .init.text >> to .text and so the code isn't freed after booting or module loading. >> (OK, you could fix this by marking the driver structs as __ref and >> keep __init for the bind functions.) > > I believe this to be untrue. __ref puts code in .ref.text which AFAIK is > freed. I'm pretty sure it's not freed. .ref.text is of course correct.
>> - Using __ref might hide section mismatches. (Your patch hasn't this >> problem as the bind functions used to live in .init.text, so any >> reference to .init should be OK assuming that it was OK to live in >> .init.text in the first place. But when marking the driver structs >> this is an issue.) That's why I don't like __ref and said my patch >> were better as it doesn't make use of it. >> >> - The bind functions are only called at init time, so there is no need >> to save a pointer to it. > > OK, I see some merit in this approach. However, the same issue is with > usb_configuration and ?usb_composite_driver -- those should be changed > in the same way or it would defeat the purpose of the patch. I didn't skip these on purpose. I just stumbled over the gadget drivers first. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
