diff --git a/bpf.c b/bpf.c
index 97f0d5b..8eacab8 100644
--- a/bpf.c
+++ b/bpf.c
@@ -10,18 +10,6 @@
 
 #include "bpf.h"
 
-/* Basic BPF instruction setter. */
-inline size_t set_bpf_instr(struct sock_filter *instr,
-		unsigned short code, unsigned int k,
-		unsigned char jt, unsigned char jf)
-{
-	instr->code = code;
-	instr->k = k;
-	instr->jt = jt;
-	instr->jf = jf;
-	return 1U;
-}
-
 /* Architecture validation. */
 size_t bpf_validate_arch(struct sock_filter *filter)
 {
diff --git a/bpf.h b/bpf.h
index d5010d9..cfa6d3e 100644
--- a/bpf.h
+++ b/bpf.h
@@ -137,9 +137,16 @@
 };
 
 /* BPF instruction manipulation functions and macros. */
-inline size_t set_bpf_instr(struct sock_filter *instr,
-		unsigned short code, unsigned int k,
-		unsigned char jt, unsigned char jf);
+static inline size_t set_bpf_instr(struct sock_filter *instr,
+	unsigned short code, unsigned int k,
+	unsigned char jt, unsigned char jf)
+{
+	instr->code = code;
+	instr->k = k;
+	instr->jt = jt;
+	instr->jf = jf;
+	return 1U;
+}
 
 #define set_bpf_stmt(_block, _code, _k) \
 	set_bpf_instr((_block), (_code), (_k), 0, 0)