From: Jens Axboe <axboe@fb.com>
Date: Mon, 24 Nov 2014 01:41:11 +0000 (-0700)
Subject: lfsr: don't pass in last value to lfsr_next()
X-Git-Tag: fio-2.2.0~48
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=6f49f8bc80fbeff3d24cf84278d2611db0ec6f6c

lfsr: don't pass in last value to lfsr_next()

It's cached in the 'fl' struct. This means we can move the max
block calculation outside if the lfsr part, too.

Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/io_u.c b/io_u.c
index c51982d8..33c82f2c 100644
--- a/io_u.c
+++ b/io_u.c
@@ -83,13 +83,15 @@ struct rand_off {
 static int __get_next_rand_offset(struct thread_data *td, struct fio_file *f,
 				  enum fio_ddir ddir, uint64_t *b)
 {
-	uint64_t r, lastb;
-
-	lastb = last_block(td, f, ddir);
-	if (!lastb)
-		return 1;
+	uint64_t r;
 
 	if (td->o.random_generator == FIO_RAND_GEN_TAUSWORTHE) {
+		uint64_t lastb;
+
+		lastb = last_block(td, f, ddir);
+		if (!lastb)
+			return 1;
+
 		r = __rand(&td->random_state);
 
 		dprint(FD_RANDOM, "off rand %llu\n", (unsigned long long) r);
@@ -98,7 +100,7 @@ static int __get_next_rand_offset(struct thread_data *td, struct fio_file *f,
 	} else {
 		uint64_t off = 0;
 
-		if (lfsr_next(&f->lfsr, &off, lastb))
+		if (lfsr_next(&f->lfsr, &off))
 			return 1;
 
 		*b = off;
diff --git a/lib/lfsr.c b/lib/lfsr.c
index 9fff50d7..0c0072cc 100644
--- a/lib/lfsr.c
+++ b/lib/lfsr.c
@@ -124,7 +124,7 @@ static inline void __lfsr_next(struct fio_lfsr *fl, unsigned int spin)
  * c. Check if the calculated value exceeds the desirable range. In this case,
  *    go back to b, else return.
  */
-int lfsr_next(struct fio_lfsr *fl, uint64_t *off, uint64_t last)
+int lfsr_next(struct fio_lfsr *fl, uint64_t *off)
 {
 	if (fl->num_vals++ > fl->max_val)
 		return 1;
diff --git a/lib/lfsr.h b/lib/lfsr.h
index 187abf2f..c2d55693 100644
--- a/lib/lfsr.h
+++ b/lib/lfsr.h
@@ -22,7 +22,7 @@ struct fio_lfsr {
 	unsigned int spin;
 };
 
-int lfsr_next(struct fio_lfsr *fl, uint64_t *off, uint64_t);
+int lfsr_next(struct fio_lfsr *fl, uint64_t *off);
 int lfsr_init(struct fio_lfsr *fl, uint64_t size,
 		unsigned long seed, unsigned int spin);
 int lfsr_reset(struct fio_lfsr *fl, unsigned long seed);