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authorRoland Dreier <roland@topspin.com>2005-04-16 15:26:06 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:26:06 -0700
commite6ded99cbbbfef2cef537d717ad61d2f77f4dfd6 (patch)
tree44ef73e8f9ac7bdfc71ff3286e6b2715aafbbd9d /drivers/infiniband/ulp/ipoib/ipoib_multicast.c
parent62241eb497721be7640e5d9330e60f4a88a4db46 (diff)
[PATCH] IPoIB: fix static rate calculation
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 <roland@topspin.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/infiniband/ulp/ipoib/ipoib_multicast.c')
-rw-r--r--drivers/infiniband/ulp/ipoib/ipoib_multicast.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index f46932dc81c..70208c3d21e 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -258,13 +258,12 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
.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,