Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[karo-tx-linux.git] / net / netfilter / xt_hashlimit.c

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 26ef70c50e3b3e6b1b2fa71f76a3ecb25768f140..2a6dfe8b74d37f7d3d8ed0569650f6417b76d58a 100644 (file)
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -463,23 +463,16 @@ static u32 xt_hashlimit_len_to_chunks(u32 len)
 /* Precision saver. */
 static u64 user2credits(u64 user, int revision)
 {
-       if (revision == 1) {
-               /* If multiplying would overflow... */
-               if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY_v1))
-                       /* Divide first. */
-                       return div64_u64(user, XT_HASHLIMIT_SCALE)
-                               * HZ * CREDITS_PER_JIFFY_v1;
-
-               return div64_u64(user * HZ * CREDITS_PER_JIFFY_v1,
-                                XT_HASHLIMIT_SCALE);
-       } else {
-               if (user > 0xFFFFFFFFFFFFFFFFULL / (HZ*CREDITS_PER_JIFFY))
-                       return div64_u64(user, XT_HASHLIMIT_SCALE_v2)
-                               * HZ * CREDITS_PER_JIFFY;
+       u64 scale = (revision == 1) ?
+               XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
+       u64 cpj = (revision == 1) ?
+               CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
 
-               return div64_u64(user * HZ * CREDITS_PER_JIFFY,
-                                XT_HASHLIMIT_SCALE_v2);
-       }
+       /* Avoid overflow: divide the constant operands first */
+       if (scale >= HZ * cpj)
+               return div64_u64(user, div64_u64(scale, HZ * cpj));
+
+       return user * div64_u64(HZ * cpj, scale);
 }
 
 static u32 user2credits_byte(u32 user)