We recently got an lkp warning about missing declarations, as in e.g. [0]. This warning is largely redundant with -Wmissing-prototypes, which we already disable for kfuncs that have global linkage and are meant to be exported in BTF, and called from BPF programs. Let's also disable -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to reproduce the warning even on W <= 3, so I can't actually be 100% sure this fixes the issue. [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@xxxxxxxxx/ Reported-by: kernel test robot <lkp@xxxxxxxxx> Closes: https://lore.kernel.org/oe-kbuild-all/202308162115.Hn23vv3n-lkp@xxxxxxxxx/ Signed-off-by: David Vernet <void@xxxxxxxxxxxxx> --- Documentation/bpf/kfuncs.rst | 4 +++- kernel/bpf/bpf_iter.c | 2 ++ kernel/bpf/cpumask.c | 2 ++ kernel/bpf/helpers.c | 2 ++ kernel/bpf/map_iter.c | 2 ++ kernel/cgroup/rstat.c | 2 ++ kernel/trace/bpf_trace.c | 2 ++ net/bpf/test_run.c | 2 ++ net/core/filter.c | 4 ++++ net/core/xdp.c | 2 ++ net/ipv4/fou_bpf.c | 2 ++ net/netfilter/nf_conntrack_bpf.c | 2 ++ net/netfilter/nf_nat_bpf.c | 2 ++ net/xfrm/xfrm_interface_bpf.c | 2 ++ tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 2 ++ 15 files changed, 33 insertions(+), 1 deletion(-) diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index 0d2647fb358d..62ce5a7b92b4 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -36,10 +36,12 @@ prototype in a header for the wrapper kfunc. An example is given below:: - /* Disables missing prototype warnings */ + /* Disables missing prototypes and declarations warnings */ __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global kfuncs as their definitions will be in BTF"); + __diag_ignore_all("-Wmissing-declarations", + "Global kfuncs as their definitions will be in BTF"); __bpf_kfunc struct task_struct *bpf_find_get_task_by_vpid(pid_t nr) { diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 96856f130cbf..b8def6e4e5e8 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -785,6 +785,8 @@ struct bpf_iter_num_kern { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) { diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index 6983af8e093c..111b0e062e7f 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -37,6 +37,8 @@ static bool cpu_valid(u32 cpu) __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global kfuncs as their definitions will be in BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global kfuncs as their definitions will be in BTF"); /** * bpf_cpumask_create() - Create a mutable BPF cpumask. diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index eb91cae0612a..6d2f84371892 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1885,6 +1885,8 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) { diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c index 6fc9dae9edc8..f7c7c5044630 100644 --- a/kernel/bpf/map_iter.c +++ b/kernel/bpf/map_iter.c @@ -196,6 +196,8 @@ late_initcall(bpf_map_iter_init); __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map) { diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 2542c21b6b6d..f5231a58ad3c 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -162,6 +162,8 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "kfuncs which will be used in BPF programs"); +__diag_ignore_all("-Wmissing-declarations", + "kfuncs which will be used in BPF programs"); __weak noinline void bpf_rstat_flush(struct cgroup *cgrp, struct cgroup *parent, int cpu) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 792445e1f3f0..1fa197aa428c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1224,6 +1224,8 @@ static const struct bpf_func_proto bpf_get_func_arg_cnt_proto = { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "kfuncs which will be used in BPF programs"); +__diag_ignore_all("-Wmissing-declarations", + "kfuncs which will be used in BPF programs"); /** * bpf_lookup_user_key - lookup a key by its serial diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 57a7a64b84ed..38aedb720a52 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -506,6 +506,8 @@ static int bpf_test_finish(const union bpf_attr *kattr, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc int bpf_fentry_test1(int a) { return a + 1; diff --git a/net/core/filter.c b/net/core/filter.c index a094694899c9..c2b32b94c6bd 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -11727,6 +11727,8 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id) __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc int bpf_dynptr_from_skb(struct sk_buff *skb, u64 flags, struct bpf_dynptr_kern *ptr__uninit) { @@ -11808,6 +11810,8 @@ late_initcall(bpf_kfunc_init); __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); /* bpf_sock_destroy: Destroy the given socket with ECONNABORTED error code. * diff --git a/net/core/xdp.c b/net/core/xdp.c index a70670fe9a2d..3d14e7be411d 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -699,6 +699,8 @@ struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf) __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); /** * bpf_xdp_metadata_rx_timestamp - Read XDP frame RX timestamp. diff --git a/net/ipv4/fou_bpf.c b/net/ipv4/fou_bpf.c index 3760a14b6b57..2b394703770a 100644 --- a/net/ipv4/fou_bpf.c +++ b/net/ipv4/fou_bpf.c @@ -25,6 +25,8 @@ enum bpf_fou_encap_type { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in BTF"); /* bpf_skb_set_fou_encap - Set FOU encap parameters * diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c index c7a6114091ae..e24e2e4b2d49 100644 --- a/net/netfilter/nf_conntrack_bpf.c +++ b/net/netfilter/nf_conntrack_bpf.c @@ -233,6 +233,8 @@ static int _nf_conntrack_btf_struct_access(struct bpf_verifier_log *log, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in nf_conntrack BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in nf_conntrack BTF"); /* bpf_xdp_ct_alloc - Allocate a new CT entry * diff --git a/net/netfilter/nf_nat_bpf.c b/net/netfilter/nf_nat_bpf.c index 141ee7783223..e903a6eb732e 100644 --- a/net/netfilter/nf_nat_bpf.c +++ b/net/netfilter/nf_nat_bpf.c @@ -15,6 +15,8 @@ __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in nf_nat BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in nf_nat BTF"); /* bpf_ct_set_nat_info - Set source or destination nat address * diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c index d74f3fd20f2b..d40060bcc398 100644 --- a/net/xfrm/xfrm_interface_bpf.c +++ b/net/xfrm/xfrm_interface_bpf.c @@ -30,6 +30,8 @@ struct bpf_xfrm_info { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in xfrm_interface BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in xfrm_interface BTF"); /* bpf_skb_get_xfrm_info - Get XFRM metadata * diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index cefc5dd72573..201a41cd47e5 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -42,6 +42,8 @@ struct bpf_testmod_struct_arg_4 { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in bpf_testmod.ko BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in bpf_testmod.ko BTF"); noinline int bpf_testmod_test_struct_arg_1(struct bpf_testmod_struct_arg_2 a, int b, int c) { -- 2.41.0
