From 62c3d0260cb8820ab50dc2ec28d9b0dd95b0690f Mon Sep 17 00:00:00 2001
From: Quentin Young <qlyoung@cumulusnetworks.com>
Date: Tue, 11 Jul 2017 11:14:09 -0400
Subject: [PATCH] lib: use 32-bit atomics, s/pow/mul

Some platforms don't support 64-bit atomics, missed converting a
floating point pow() to an integral mul when changing SD algo.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
---
 lib/hash.c | 9 ++-------
 lib/hash.h | 4 ++--
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/lib/hash.c b/lib/hash.c
index 95643bbae0..57a07b5f8e 100644
--- a/lib/hash.c
+++ b/lib/hash.c
@@ -87,13 +87,8 @@ hash_alloc_intern (void *arg)
 }
 
 #define hash_update_ssq(hz, old, new) \
-  do { \
-    long double res; \
-    res = powl(old, 2.0); \
-    hz->stats.ssq -= (uint64_t) res;\
-    res = powl(new, 2.0); \
-    hz->stats.ssq += (uint64_t) res; \
-  } while (0); \
+    atomic_fetch_add_explicit(&hz->stats.ssq, (new + old)*(new - old),\
+                              memory_order_relaxed);
 
 /* Expand hash if the chain length exceeds the threshold. */
 static void hash_expand (struct hash *hash)
diff --git a/lib/hash.h b/lib/hash.h
index 01d2b1ddc8..3b2671afae 100644
--- a/lib/hash.h
+++ b/lib/hash.h
@@ -53,9 +53,9 @@ struct hash_backet
 struct hashstats
 {
   /* number of empty hash buckets */
-  _Atomic int empty;
+  _Atomic uint_fast32_t empty;
   /* sum of squares of bucket length */
-  _Atomic uint64_t ssq;
+  _Atomic uint_fast32_t ssq;
 };
 
 struct hash