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authorShawn Landden <shawn@churchofgit.com>2015-05-05 09:07:16 -0700
committerMarc Kleine-Budde <mkl@pengutronix.de>2015-05-06 08:03:19 +0200
commita2f11835994ed5bcd6d66c7205947cc482231b08 (patch)
treed6c14658230c9fb468403a5b6078deee3ac9b9e4
parent239fb791d4ee194740e69fe9694f58ec404d1689 (diff)
can.h: make padding given by gcc explicit
The current definition of struct can_frame has a 16-byte size, with 8-byte alignment, but the 3 bytes of padding are not explicit like the similar 2 bytes of padding of struct canfd_frame. Make it explicit so it is easier to read. Signed-off-by: Shawn Landden <shawn@churchofgit.com> Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
-rw-r--r--Documentation/networking/can.txt3
-rw-r--r--include/uapi/linux/can.h6
2 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index 5abad1e921ca..b48d4a149411 100644
--- a/Documentation/networking/can.txt
+++ b/Documentation/networking/can.txt
@@ -268,6 +268,9 @@ solution for a couple of reasons:
struct can_frame {
canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
__u8 can_dlc; /* frame payload length in byte (0 .. 8) */
+ __u8 __pad; /* padding */
+ __u8 __res0; /* reserved / padding */
+ __u8 __res1; /* reserved / padding */
__u8 data[8] __attribute__((aligned(8)));
};
diff --git a/include/uapi/linux/can.h b/include/uapi/linux/can.h
index 41892f720057..9692cda5f8fc 100644
--- a/include/uapi/linux/can.h
+++ b/include/uapi/linux/can.h
@@ -95,11 +95,17 @@ typedef __u32 can_err_mask_t;
* @can_dlc: frame payload length in byte (0 .. 8) aka data length code
* N.B. the DLC field from ISO 11898-1 Chapter 8.4.2.3 has a 1:1
* mapping of the 'data length code' to the real payload length
+ * @__pad: padding
+ * @__res0: reserved / padding
+ * @__res1: reserved / padding
* @data: CAN frame payload (up to 8 byte)
*/
struct can_frame {
canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
__u8 can_dlc; /* frame payload length in byte (0 .. CAN_MAX_DLEN) */
+ __u8 __pad; /* padding */
+ __u8 __res0; /* reserved / padding */
+ __u8 __res1; /* reserved / padding */
__u8 data[CAN_MAX_DLEN] __attribute__((aligned(8)));
};