Technically it is fine (on all current Linux architectures) to store a pointer in an unsigned long variable. However this needs explicit casting which is an easy source for type mismatches.
By replacing the plain unsigned long .driver_data in struct zorro_device_id by an anonymous union, most of the casting can be dropped. There is still some implicit casting involved (between a void * and a driver specific pointer type), but that's better than the approach to store a pointer in an unsigned long variable as this doesn't lose the information that the data being pointed to is const. All users of struct zorro_device_id are initialized in a way that is compatible with the new definition, so no adaptions are needed there. Signed-off-by: Uwe Kleine-König (The Capable Hub) <[email protected]> --- include/linux/mod_devicetable.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 3b0c9a251a2e..2673a1bd82c4 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -640,7 +640,11 @@ struct mdio_device_id { struct zorro_device_id { __u32 id; /* Device ID or ZORRO_WILDCARD */ - kernel_ulong_t driver_data; /* Data private to the driver */ + union { + /* Data private to the driver */ + kernel_ulong_t driver_data; + const void *driver_data_ptr; + }; }; #define ZORRO_WILDCARD (0xffffffff) /* not official */ -- 2.47.3
