X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=lib%2Flfsr.c;h=0c0072ccb39b15e970eeb6bd92342b67a85cd8bb;hp=927b2a10cdeeefc4441a9b7aa720677b6939a9be;hb=29dbd1e5f1f7e3465acaa26a55cc29259f0eb61b;hpb=d56036a40edce5619d6e9346b1e9d34822ab1437

diff --git a/lib/lfsr.c b/lib/lfsr.c
index 927b2a10..0c0072cc 100644
--- a/lib/lfsr.c
+++ b/lib/lfsr.c
@@ -2,6 +2,7 @@
 #include <math.h>
 
 #include "lfsr.h"
+#include "../compiler/compiler.h"
 
 /*
  * LFSR taps retrieved from:
@@ -10,7 +11,7 @@
  * The memory overhead of the following tap table should be relatively small,
  * no more than 400 bytes.
  */
-static uint8_t taps[64][FIO_MAX_TAPS] =
+static uint8_t lfsr_taps[64][FIO_MAX_TAPS] =
 {
 	{0}, {0}, {0},		//LFSRs with less that 3-bits cannot exist
 	{3, 2},			//Tap position for 3-bit LFSR
@@ -123,7 +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;
@@ -132,11 +133,9 @@ int lfsr_next(struct fio_lfsr *fl, uint64_t *off, uint64_t last)
 		if (fl->cycle_length && !--fl->cycle_length) {
 			__lfsr_next(fl, fl->spin + 1);
 			fl->cycle_length = fl->cached_cycle_length;
-			goto check;
-		}
-		__lfsr_next(fl, fl->spin);
-check: ;
-	} while (fl->last_val > fl->max_val);
+		} else
+			__lfsr_next(fl, fl->spin);
+	} while (fio_unlikely(fl->last_val > fl->max_val));
 
 	*off = fl->last_val;
 	return 0;
@@ -159,12 +158,12 @@ static uint8_t *find_lfsr(uint64_t size)
 
 	/*
 	 * For an LFSR, there is always a prohibited state (all ones).
-	 * Thus, if we need to find the proper LFSR for our size, we must take that
-	 * into account.
+	 * Thus, if we need to find the proper LFSR for our size, we must
+	 * take that into account.
 	 */
 	for (i = 3; i < 64; i++)
 		if ((1UL << i) > size)
-			return taps[i];
+			return lfsr_taps[i];
 
 	return NULL;
 }
@@ -187,7 +186,7 @@ static uint8_t *find_lfsr(uint64_t size)
  * Thus, [1] is equivalent to (y * i) % (spin + 1) == 0;
  * Also, the cycle's length will be (x * i) + (y * i) / (spin + 1)
  */
-int prepare_spin(struct fio_lfsr *fl, unsigned int spin)
+static int prepare_spin(struct fio_lfsr *fl, unsigned int spin)
 {
 	uint64_t max = (fl->cached_bit << 1) - 1;
 	uint64_t x, y;
@@ -235,15 +234,15 @@ int lfsr_reset(struct fio_lfsr *fl, unsigned long seed)
 int lfsr_init(struct fio_lfsr *fl, uint64_t nums, unsigned long seed,
 		unsigned int spin)
 {
-	uint8_t *lfsr_taps;
+	uint8_t *taps;
 
-	lfsr_taps = find_lfsr(nums);
-	if (!lfsr_taps)
+	taps = find_lfsr(nums);
+	if (!taps)
 		return 1;
 
 	fl->max_val = nums - 1;
-	fl->xormask = lfsr_create_xormask(lfsr_taps);
-	fl->cached_bit = 1UL << (lfsr_taps[0] - 1);
+	fl->xormask = lfsr_create_xormask(taps);
+	fl->cached_bit = 1UL << (taps[0] - 1);
 
 	if (prepare_spin(fl, spin))
 		return 1;