From: Uwe Kleine-König (The Capable Hub) Date: Mon, 11 May 2026 10:45:02 +0000 (+0200) Subject: firewire: Simplify storing pointers in device id struct X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=39d260d6bc7aab6777c0d14d1e27648ca8e9252e;p=thirdparty%2Flinux.git firewire: Simplify storing pointers in device id struct 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 ieee1394_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 ieee1394_device_id are initialized in a way that is compatible with the new definition, so no adaptions are needed there. (The comments addressing to CHERI extension are dropped by the maintainer.) Signed-off-by: Uwe Kleine-König (The Capable Hub) Link: https://lore.kernel.org/r/e5ba45a7e386461c0b1a5001635aa008b01c2164.1778494204.git.u.kleine-koenig@baylibre.com Signed-off-by: Takashi Sakamoto --- diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 23ff24080dfd9..3b0c9a251a2e9 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -61,7 +61,10 @@ struct ieee1394_device_id { __u32 model_id; __u32 specifier_id; __u32 version; - kernel_ulong_t driver_data; + union { + kernel_ulong_t driver_data; + const void *driver_data_ptr; + }; };