From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 21 Jan 2013 16:42:49 +0000 (-0700)
Subject: lfsr: add lfsr_reset()
X-Git-Tag: fio-2.0.14~114
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=0415406ff0a7ced100565c4cba1322705b7fdb0a;ds=sidebyside

lfsr: add lfsr_reset()

This enables us to restart a sequence.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/lib/lfsr.c b/lib/lfsr.c
index 975c6a5a..61a3aaf3 100644
--- a/lib/lfsr.c
+++ b/lib/lfsr.c
@@ -244,6 +244,17 @@ static struct lfsr_taps *find_lfsr(uint64_t size)
 	return NULL;
 }
 
+void lfsr_reset(struct fio_lfsr *fl, unsigned long seed)
+{
+	unsigned int i;
+
+	fl->last_val = seed;
+	fl->num_vals = 0;
+
+	for (i = 0; i < FIO_LFSR_CRANKS; i++)
+		fl->last_val = __lfsr_next(fl->last_val, &fl->taps);
+}
+
 int lfsr_init(struct fio_lfsr *fl, uint64_t size, unsigned long seed)
 {
 	struct lfsr_taps *tap;
@@ -253,18 +264,15 @@ int lfsr_init(struct fio_lfsr *fl, uint64_t size, unsigned long seed)
 	if (!tap)
 		return 1;
 
-	fl->last_val = seed;
 	fl->max_val = size - 1;
-	fl->num_vals = 0;
 	fl->taps.length = tap->length;
+
 	for (i = 0; i < FIO_MAX_TAPS; i++) {
 		fl->taps.taps[i] = tap->taps[i];
 		if (!fl->taps.taps[i])
 			break;
 	}
 
-	for (i = 0; i < FIO_LFSR_CRANKS; i++)
-		fl->last_val = __lfsr_next(fl->last_val, &fl->taps);
-
+	lfsr_reset(fl, seed);
 	return 0;
 }
diff --git a/lib/lfsr.h b/lib/lfsr.h
index 898646e2..45d7028c 100644
--- a/lib/lfsr.h
+++ b/lib/lfsr.h
@@ -20,5 +20,6 @@ struct fio_lfsr {
 
 int lfsr_next(struct fio_lfsr *fl, uint64_t *off, uint64_t);
 int lfsr_init(struct fio_lfsr *fl, uint64_t size, unsigned long seed);
+void lfsr_reset(struct fio_lfsr *fl, unsigned long seed);
 
 #endif