1 files changed, 22 insertions, 1 deletions

diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index 45f30f59ea2a..faf5f7e219e3 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -13,8 +13,29 @@
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  */
-
 #include <linux/types.h>
+#include <asm/div64.h>
+
+/* integer-arithmetic divisions of type (a * 1000000)/b */
+static inline u64 scaled_div(u64 a, u32 b)
+{
+        BUG_ON(b==0);
+        a *= 1000000;
+        do_div(a, b);
+        return a;
+}
+
+static inline u32 scaled_div32(u64 a, u32 b)
+{
+        u64 result = scaled_div(a, b);
+
+        if (result > UINT_MAX) {
+                DCCP_CRIT("Overflow: a(%llu)/b(%u) > ~0U",
+                          (unsigned long long)a, b);
+                return UINT_MAX;
+        }
+        return result;
+}
 
 extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
 extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);