[NETFILTER]: Fix div64_64 in ipt_connbytes

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 14 deletions

diff --git a/net/ipv4/netfilter/ipt_connbytes.c b/net/ipv4/netfilter/ipt_connbytes.c
index 0dfb52c0e808..47128c073d85 100644
--- a/net/ipv4/netfilter/ipt_connbytes.c
+++ b/net/ipv4/netfilter/ipt_connbytes.c
@@ -22,23 +22,19 @@ MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
 MODULE_DESCRIPTION("iptables match for matching number of pkts/bytes per connection");
 
 /* 64bit divisor, dividend and result. dynamic precision */
-static u_int64_t div64_64(u_int64_t divisor, u_int64_t dividend)
+static u_int64_t div64_64(u_int64_t dividend, u_int64_t divisor)
 {
-        u_int64_t result = divisor;
-
-        if (dividend > 0xffffffff) {
-                int first_bit = find_first_bit((unsigned long *) &dividend, sizeof(dividend));
-                /* calculate number of bits to shift. shift exactly enough
-                 * bits to make dividend fit in 32bits. */
-                int num_shift = (64 - 32 - first_bit);
-                /* first bit has to be < 32, since dividend was > 0xffffffff */
-                result = result >> num_shift;
-                dividend = dividend >> num_shift;
-        }
+        u_int32_t d = divisor;
+
+        if (divisor > 0xffffffffULL) {
+                unsigned int shift = fls(divisor >> 32);
 
-        do_div(divisor, dividend);
+                d = divisor >> shift;
+                dividend >>= shift;
+        }
 
-        return divisor;
+        do_div(dividend, d);
+        return dividend;
 }
 
 static int