Re: [PATCH] can: rockchip_canfd: fix return type of rkcanfd_start_xmit()

[Nathan Chancellor <nathan@kernel.org>]

Hi Marc,

On Mon, Sep 09, 2024 at 10:57:06AM +0200, Marc Kleine-Budde wrote:
> On 09.09.2024 09:44:48, Simon Horman wrote:
> > On Fri, Sep 06, 2024 at 01:26:41PM -0700, Nathan Chancellor wrote:
> > >   drivers/net/can/rockchip/rockchip_canfd-core.c:770:20: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> > >     770 |         .ndo_start_xmit = rkcanfd_start_xmit,
> > >         |                           ^~~~~~~~~~~~~~~~~~
...
> FTR: the default clang in Debian unstable, clang-16.0.6 doesn't support
> this. With clang-20 from experimental it works, haven't checked older
> versions, though.

Hmmm, interesting, the patch that added
-Wincompatible-function-pointer-types-strict was added in LLVM 16, so it
should work for 16.0.6...

https://github.com/llvm/llvm-project/commits/41ce74e6e983f523d44d3a80be5ae778c35df85a

I don't have easy access to Debian at the moment so I can double check
it later. I would like to get this turned on for the whole kernel soon
but there is still one subsystem that has several instances that I have
not been able to workaround at this point so I've just stuck to adding
it via KCFLAGS when testing.

Cheers,
Nathan