[PATCH] Signedness warning

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.c b/fio.c
index 52caa4e..76710e1 100644
--- a/fio.c
+++ b/fio.c
@@ -482,9 +482,9 @@
 /*
  * "randomly" fill the buffer contents
  */
-static void fill_rand_buf(struct io_u *io_u, unsigned int max_bs)
+static void fill_rand_buf(struct io_u *io_u, int max_bs)
 {
-	unsigned int *ptr = io_u->buf;
+	int *ptr = io_u->buf;
 
 	while ((void *) ptr - io_u->buf < max_bs) {
 		*ptr = rand() * 0x9e370001;