diff --git a/tools/perf/util/strbuf.h b/tools/perf/util/strbuf.h
index 7a32c83..b73cbaa 100644
--- a/tools/perf/util/strbuf.h
+++ b/tools/perf/util/strbuf.h
@@ -51,16 +51,16 @@
 #define STRBUF_INIT  { 0, 0, strbuf_slopbuf }
 
 /*----- strbuf life cycle -----*/
-extern void strbuf_init(struct strbuf *buf, ssize_t hint);
-extern void strbuf_release(struct strbuf *);
-extern char *strbuf_detach(struct strbuf *, size_t *);
+void strbuf_init(struct strbuf *buf, ssize_t hint);
+void strbuf_release(struct strbuf *buf);
+char *strbuf_detach(struct strbuf *buf, size_t *);
 
 /*----- strbuf size related -----*/
 static inline ssize_t strbuf_avail(const struct strbuf *sb) {
 	return sb->alloc ? sb->alloc - sb->len - 1 : 0;
 }
 
-extern void strbuf_grow(struct strbuf *, size_t);
+void strbuf_grow(struct strbuf *buf, size_t);
 
 static inline void strbuf_setlen(struct strbuf *sb, size_t len) {
 	if (!sb->alloc)
@@ -77,16 +77,16 @@
 	sb->buf[sb->len] = '\0';
 }
 
-extern void strbuf_add(struct strbuf *, const void *, size_t);
+void strbuf_add(struct strbuf *buf, const void *, size_t);
 static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
 	strbuf_add(sb, s, strlen(s));
 }
 
 __attribute__((format(printf,2,3)))
-extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
-extern void strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap);
+void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
+void strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap);
 
 /* XXX: if read fails, any partial read is undone */
-extern ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint);
+ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint);
 
 #endif /* __PERF_STRBUF_H */