From: Roland Dreier Correct and simplify calculation of static rate. We need to round up the quotient of (local_rate - path_rate) / path_rate. To round up we add (path_rate - 1) to the numerator, so the quotient simplifies to (local_rate - 1) / path_rate. No idea how I came up with the old formula. Signed-off-by: Roland Dreier Signed-off-by: Andrew Morton --- 25-akpm/drivers/infiniband/ulp/ipoib/ipoib_main.c | 7 +++---- 25-akpm/drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 7 +++---- 2 files changed, 6 insertions(+), 8 deletions(-) diff -puN drivers/infiniband/ulp/ipoib/ipoib_main.c~ipoib-fix-static-rate-calculation drivers/infiniband/ulp/ipoib/ipoib_main.c --- 25/drivers/infiniband/ulp/ipoib/ipoib_main.c~ipoib-fix-static-rate-calculation Fri Apr 1 13:20:25 2005 +++ 25-akpm/drivers/infiniband/ulp/ipoib/ipoib_main.c Fri Apr 1 13:20:25 2005 @@ -302,11 +302,10 @@ static void path_rec_completion(int stat .sl = pathrec->sl, .port_num = priv->port }; + int path_rate = ib_sa_rate_enum_to_int(pathrec->rate); - if (ib_sa_rate_enum_to_int(pathrec->rate) > 0) - av.static_rate = (2 * priv->local_rate - - ib_sa_rate_enum_to_int(pathrec->rate) - 1) / - (priv->local_rate ? priv->local_rate : 1); + if (path_rate > 0 && priv->local_rate > path_rate) + av.static_rate = (priv->local_rate - 1) / path_rate; ipoib_dbg(priv, "static_rate %d for local port %dX, path %dX\n", av.static_rate, priv->local_rate, diff -puN drivers/infiniband/ulp/ipoib/ipoib_multicast.c~ipoib-fix-static-rate-calculation drivers/infiniband/ulp/ipoib/ipoib_multicast.c --- 25/drivers/infiniband/ulp/ipoib/ipoib_multicast.c~ipoib-fix-static-rate-calculation Fri Apr 1 13:20:25 2005 +++ 25-akpm/drivers/infiniband/ulp/ipoib/ipoib_multicast.c Fri Apr 1 13:20:25 2005 @@ -258,13 +258,12 @@ static int ipoib_mcast_join_finish(struc .traffic_class = mcast->mcmember.traffic_class } }; + int path_rate = ib_sa_rate_enum_to_int(mcast->mcmember.rate); av.grh.dgid = mcast->mcmember.mgid; - if (ib_sa_rate_enum_to_int(mcast->mcmember.rate) > 0) - av.static_rate = (2 * priv->local_rate - - ib_sa_rate_enum_to_int(mcast->mcmember.rate) - 1) / - (priv->local_rate ? priv->local_rate : 1); + if (path_rate > 0 && priv->local_rate > path_rate) + av.static_rate = (priv->local_rate - 1) / path_rate; ipoib_dbg_mcast(priv, "static_rate %d for local port %dX, mcmember %dX\n", av.static_rate, priv->local_rate, _