diff --git a/src/mux_h1.c b/src/mux_h1.c
index d2acee6a3..cb70b84b4 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -4633,6 +4633,7 @@ static int h1_fastfwd(struct stconn *sc, unsigned int count, unsigned int flags)
 	}
 
 	total += sdo->iobuf.data;
+	count -= sdo->iobuf.data;
 #if defined(USE_LINUX_SPLICE)
 	if (sdo->iobuf.pipe) {
 		/* Here, not data was xferred */