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Date:   Sat, 14 May 2022 13:17:26 +0200
From:   Max Staudt <max@enpas.org>
To:     Vincent MAILHOL <mailhol.vincent@wanadoo.fr>
Cc:     kernel test robot <lkp@intel.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>, llvm@lists.linux.dev,
        kbuild-all@lists.01.org, linux-can@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] can: skb:: move can_dropped_invalid_skb and
 can_skb_headroom_valid to skb.c
Message-ID: <20220514131726.55fbbcdb.max@enpas.org>
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On Sat, 14 May 2022 14:16:09 +0900
Vincent MAILHOL <mailhol.vincent@wanadoo.fr> wrote:

> OK, so the issue is that VCAN and VXCAN are users of
> can_dropped_invalid_skb() but do not depend on CAN_DEV. Above error
> will appear if CONFIG_CAN_DEV is not set (or if CONFIG_V{,X}CAN is set
> to "yes" and CAN_DEV is set to "module").
> I see three choices here:
>   1. move can_dropped_invalid_skb() outside of drivers/net/can (i.e.
> move it somewhere in net/can).
>   2. split CAN_DEV into one additional sub module: CAN_SKB and add a
> dependency to it in VCAN and VXCAN.
>   3. Add a dependency to CAN_DEV in VCAN and VXCAN
> 
> 1. is I think the worse, 2. the best, 3. is the laziest option and is
> kind of acceptable.
> @Marc (and anyone else), what are your thoughts?

I think that having v(x)can depend on can-dev isn't half bad - for the
user, they are CAN devices, anyway, and modprobe does the dependency
resolution magic.

Splitting into too many modules is something I'd avoid because of the
overhead involved.


Max