[NET_SCHED]: Cleanup L2T macros and handle oversized packets

Change L2T (length to time) macros, in all rate based schedulers, to
call a common function qdisc_l2t() that does the rate table lookup.
This function handles if the packet size lookup is larger than the
rate table, which often occurs with TSO enabled.

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 8a67f24cbe02..4ebd615bd013 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -302,4 +302,16 @@ drop:
         return NET_XMIT_DROP;
 }
 
+/* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
+   long it will take to send a packet given its size.
+ */
+static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
+{
+        int slot = pktlen;
+        slot >>= rtab->rate.cell_log;
+        if (slot > 255)
+                return (rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF]);
+        return rtab->data[slot];
+}
+
 #endif