Re: [PATCH 12/12] [RFC] can: avoid using timeval for uapi

On 10/06/2015 10:32 AM, Arnd Bergmann wrote:

On Monday 05 October 2015 20:51:08 Oliver Hartkopp wrote:

quoted

I double checked some (more) BCM applications I have access to.

E.g. https://github.com/linux-can/can-tests

When you do a 'git grep ival1' there you get something like

tst-bcm-cycle.c:        msg.msg_head.ival1.tv_sec = 1;
tst-bcm-cycle.c:        msg.msg_head.ival1.tv_usec = 0;
tst-bcm-cycle.c:        msg.msg_head.ival1.tv_sec = 0;
tst-bcm-cycle.c:        msg.msg_head.ival1.tv_usec = 0;
tst-bcm-dump.c: msg.msg_head.ival1.tv_sec       = timeout / 1000000;
tst-bcm-dump.c: msg.msg_head.ival1.tv_usec      = timeout % 1000000;
(..)

So the usual way to assign values to ival1 and ival2 is NOT to assign an
existing struct timeval but to directly assign its tv_[u]sec elements.

Ok, very good.

quoted

I applied your bcm.h changes to my local can-tests tree and it compiles
without any problems - as expected. I don't see any serious drawback with your
idea. I wonder whether developers would ever notice this change ...

quoted

We could address problem a) by using '__u32' or 'int' members
rather than 'long', but that would have a more significant
downside in also breaking support for all existing 64-bit user
binaries that might be using this interface, which is likely
not acceptable.

Indeed.

quoted

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>

Thanks for your good suggestion to make the BCM API y2038 proof!

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>

Thanks.

What is the normal path for CAN patches? Should I resend with your
Ack and without the RFC for Marc to pick it up?

You can add my:

Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>

add upstream the 2038 fixes as a block.

Marc
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