Ensure that buffer contents are random across jobs as well

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/lib/rand.h b/lib/rand.h
index f80c111..6b9e13c 100644
--- a/lib/rand.h
+++ b/lib/rand.h
@@ -7,8 +7,6 @@
 	unsigned int s1, s2, s3;
 };
 
-extern struct frand_state __fio_rand_state;
-
 static inline unsigned int __rand(struct frand_state *state)
 {
 #define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
@@ -23,6 +21,6 @@
 extern void init_rand(struct frand_state *);
 extern void init_rand_seed(struct frand_state *, unsigned int seed);
 extern void __fill_random_buf(void *buf, unsigned int len, unsigned long seed);
-extern unsigned long fill_random_buf(void *buf, unsigned int len);
+extern unsigned long fill_random_buf(struct frand_state *, void *buf, unsigned int len);
 
 #endif