Unlike gcc, clang warns about unused static inlines that are not in an include file: net/netfilter/core.c:344:20: error: unused function 'nf_ingress_hook' [-Werror,-Wunused-function] static inline bool nf_ingress_hook(const struct nf_hook_ops *reg, int pf) ^ net/netfilter/core.c:353:20: error: unused function 'nf_egress_hook' [-Werror,-Wunused-function] static inline bool nf_egress_hook(const struct nf_hook_ops *reg, int pf) ^ According to commit 6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build"), the proper resolution is to mark the affected functions as __maybe_unused. An alternative approach would be to move them to include/linux/netfilter_netdev.h, but since Pablo didn't do that in commit ddcfa710d40b ("netfilter: add nf_ingress_hook() helper function"), I'm guessing __maybe_unused is preferred. This fixes both the warning introduced by Pablo in v5.10 as well as the one recently introduced by myself with commit 42df6e1d221d ("netfilter: Introduce egress hook"). Fixes: ddcfa710d40b ("netfilter: add nf_ingress_hook() helper function") Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # v5.10+ --- net/netfilter/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 3a32a813fcde..6dec9cd395f1 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -341,7 +341,8 @@ static int nf_ingress_check(struct net *net, const struct nf_hook_ops *reg, return 0; } -static inline bool nf_ingress_hook(const struct nf_hook_ops *reg, int pf) +static inline bool __maybe_unused nf_ingress_hook(const struct nf_hook_ops *reg, + int pf) { if ((pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) || (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS)) @@ -350,7 +351,8 @@ static inline bool nf_ingress_hook(const struct nf_hook_ops *reg, int pf) return false; } -static inline bool nf_egress_hook(const struct nf_hook_ops *reg, int pf) +static inline bool __maybe_unused nf_egress_hook(const struct nf_hook_ops *reg, + int pf) { return pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_EGRESS; } -- 2.31.1