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authorKurt Van Dijck <dev.kurt@vandijck-laurijssen.be>2018-10-08 12:48:33 +0300
committerMarc Kleine-Budde <mkl@pengutronix.de>2019-09-04 14:29:15 +0300
commit9868b5d44f3df9dd75247acd23dddff0a42f79be (patch)
treec12df929a819d45fab12295ea93c3c5d4d00aa10 /include/linux/can
parent4f746fb4951834ba71d590d430f27dee54f9d9a0 (diff)
downloadlinux-9868b5d44f3df9dd75247acd23dddff0a42f79be.tar.xz
can: introduce CAN_REQUIRED_SIZE macro
The size of this structure will be increased with J1939 support. To stay binary compatible, the CAN_REQUIRED_SIZE macro is introduced for existing CAN protocols. Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'include/linux/can')
-rw-r--r--include/linux/can/core.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/can/core.h b/include/linux/can/core.h
index 708c10d3417a..8339071ab08b 100644
--- a/include/linux/can/core.h
+++ b/include/linux/can/core.h
@@ -41,6 +41,14 @@ struct can_proto {
struct proto *prot;
};
+/* required_size
+ * macro to find the minimum size of a struct
+ * that includes a requested member
+ */
+#define CAN_REQUIRED_SIZE(struct_type, member) \
+ (offsetof(typeof(struct_type), member) + \
+ sizeof(((typeof(struct_type) *)(NULL))->member))
+
/* function prototypes for the CAN networklayer core (af_can.c) */
extern int can_proto_register(const struct can_proto *cp);