Re: [PATCH 1/2] mlx5: only register devlink when ethernet is available

On Wed, Jun 15, 2016 at 6:27 PM, Arnd Bergmann [off-list ref] wrote:

We get a build error with the mlx5 driver when the ethernet
support (CONFIG_MLX5_CORE_EN) is disabled:

drivers/net/ethernet/mellanox/mlx5/core/main.c:1320:22: error: 'mlx5_devlink_eswitch_mode_set' undeclared here (not in a function)
drivers/net/ethernet/mellanox/mlx5/core/main.c:1321:22: error: 'mlx5_devlink_eswitch_mode_get' undeclared here (not in a function)
drivers/net/built-in.o:(.rodata+0x25a68): undefined reference to `mlx5_devlink_eswitch_mode_get'
drivers/net/built-in.o:(.rodata+0x25a6c): undefined reference to `mlx5_devlink_eswitch_mode_set'

There are actually two problems here, but they are closely related,
so I'm addressing them both:

- The header is included under an #ifdef, which is usually a bad idea
  as it hides the function declarations, so we fail to compile even
  if we don't actually use the functions in the end.
- The references to the functions are kept in the object file because
  we don't check whether they are built-in or not.

As we don't want to add any useless #ifdef here, this uses an
IS_ENABLED() check to drop the mlx5_devlink_ops structure when we don't
need it, and to skip the register/unregister step.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: f7856daf57b9 ("net/mlx5: Add devlink interface")

Hi Arnd,

We already took care of those issues, they only apply to Leon's tree
https://git.kernel.org/cgit/linux/kernel/git/leon/linux-rdma.git/,
this tree is meant to maintain MLX5 Shared code between netdev and
linux-rdma trees prior to submission to both trees.

This patch is a non-shared code and it only exists in
https://git.kernel.org/cgit/linux/kernel/git/leon/linux-rdma.git/log/?h=topic/net-next-mlx5.
It is yet to be submitted to Dave's net/net-next tree. later on, this
patch and all the others will go through the normal submission
process.

For the future I don't see any reason to CC the whole netdev, rdma and
kernel folks.
Unless you, Dave and Doug think otherwise.

Thanks
Saeed.