Re: [PATCH net v1 1/1] netfilter: conntrack: Guard possoble unused functions

[Simon Horman <horms@kernel.org>]

On Thu, Sep 05, 2024 at 11:36:12PM +0300, Andy Shevchenko wrote:
> Some of the functions may be unused, it prevents kernel builds
> with clang, `make W=1` and CONFIG_WERROR=y:
> 
> net/netfilter/nf_conntrack_netlink.c:657:22: error: unused function 'ctnetlink_acct_size' [-Werror,-Wunused-function]
>   657 | static inline size_t ctnetlink_acct_size(const struct nf_conn *ct)
>       |                      ^~~~~~~~~~~~~~~~~~~
> net/netfilter/nf_conntrack_netlink.c:667:19: error: unused function 'ctnetlink_secctx_size' [-Werror,-Wunused-function]
>   667 | static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
>       |                   ^~~~~~~~~~~~~~~~~~~~~
> net/netfilter/nf_conntrack_netlink.c:683:22: error: unused function 'ctnetlink_timestamp_size' [-Werror,-Wunused-function]
>   683 | static inline size_t ctnetlink_timestamp_size(const struct nf_conn *ct)
>       |                      ^~~~~~~~~~~~~~~~~~~~~~~~

Hi Andy,

Local testing seems to show that the warning is still emitted
for ctnetlink_label_size if CONFIG_NETFILTER_NETLINK_GLUE_CT is enabled
but CONFIG_NF_CONNTRACK_EVENTS is not.

> 
> Fix this by guarding possible unused functions with ifdeffery.
> 
> See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
> inline functions for W=1 build").
> 
> Fixes: 4a96300cec88 ("netfilter: ctnetlink: restore inlining for netlink message size calculation")

I'm not sure that this qualifies as a fix, rather I think it should
be targeted at net-next without a Fixes tag.

> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

...