Hi Damien,
On Thu, Dec 10, 2020 at 4:41 AM Damien Le Moal <damien.lemoal@xxxxxxx> wrote:
> Changes from v6:
> * Annotate struct platform_driver variables with __refdata to avoid
> section mismatch compilation errors
Blindly following the advice from kernel test robot <lkp@xxxxxxxxx> is
not always a good idea:
The variable k210_rst_driver references
the function __init set_reset_devices()
If the reference is valid then annotate the
variable with or __refdata (see linux/init.h) or name the variable:
If your driver's probe function is annotated with __init, you cannot
have a pointer to it in the driver structure, as any binding done after
the freeing of initmem will cause a crash. Adding the __refdata merely
suppresses the warning, and won't avoid the crash.
There are two solutions for this:
1. Remove the .probe pointer, and use platform_driver_probe() instead
of platform_driver_register().
This guarantees the probe method will be called only once, before
initmem is freed, but does mean that probe deferral cannot work.
2. Drop the __init annotation.
This means the probe method can be called anytime, and supports
both probe deferral and driver unbind/rebind cycles.
Given the limited amount of RAM on k210, I think option 1 is preferred,
but may require careful tuning of the initialization order using
*_initcall*(), to make sure probe deferral won't ever be needed.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
