From: Alasdair Kergon <agk@redhat.com>
Date: Mon, 19 Apr 2010 17:17:55 +0000 (+0000)
Subject: Speed up dm_bit_get_next with ffs().
X-Git-Tag: old-v2_02_64~53
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=803380c203dbe62a406db095a65254de96f5694e;p=lvm2.git

Speed up dm_bit_get_next with ffs().
---

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index eee757baa..5f22b63da 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,6 @@
 Version 1.02.47 -
 =================================
+  Speed up dm_bit_get_next with ffs().
 
 Version 1.02.46 - 14th April 2010
 =================================
diff --git a/libdm/datastruct/bitset.c b/libdm/datastruct/bitset.c
index 953916259..e3c31d75c 100644
--- a/libdm/datastruct/bitset.c
+++ b/libdm/datastruct/bitset.c
@@ -52,18 +52,11 @@ void dm_bit_union(dm_bitset_t out, dm_bitset_t in1, dm_bitset_t in2)
 		out[i] = in1[i] | in2[i];
 }
 
-/*
- * FIXME: slow
- */
-static inline int _test_word(uint32_t test, int bit)
+static int _test_word(uint32_t test, int bit)
 {
-	while (bit < (int) DM_BITS_PER_INT) {
-		if (test & (0x1 << bit))
-			return bit;
-		bit++;
-	}
+	int next_set_bit;
 
-	return -1;
+	return ((next_set_bit = ffs(test >> bit)) ? next_set_bit + bit - 1 : -1);
 }
 
 int dm_bit_get_next(dm_bitset_t bs, int last_bit)