Commit e6ded99c authored by Roland Dreier's avatar Roland Dreier Committed by Linus Torvalds

[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: default avatarRoland Dreier <roland@topspin.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 62241eb4
......@@ -302,11 +302,10 @@ static void path_rec_completion(int status,
.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,
......
......@@ -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,
......
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