diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 1650353..af42cda 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -574,7 +574,7 @@
 	return 0UL;
 }
 
-static inline unsigned long
+static inline void
 pfm_unprotect_ctx_ctxsw(pfm_context_t *x, unsigned long f)
 {
 	spin_unlock(&(x)->ctx_lock);