net_sched: red: Avoid illegal values

Check the qmin & qmax values doesn't overflow for the given Wlog value.
Check that qmin <= qmax.

Fixes: a783474591f2 ("[PKT_SCHED]: Generic RED layer")
Signed-off-by: Nogah Frankel <nogahf@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/red.h b/include/net/red.h
index 5918f78..9665582 100644
--- a/include/net/red.h
+++ b/include/net/red.h
@@ -168,6 +168,17 @@ static inline void red_set_vars(struct red_vars *v)
 	v->qcount	= -1;
 }
 
+static inline bool red_check_params(u32 qth_min, u32 qth_max, u8 Wlog)
+{
+	if (fls(qth_min) + Wlog > 32)
+		return false;
+	if (fls(qth_max) + Wlog > 32)
+		return false;
+	if (qth_max < qth_min)
+		return false;
+	return true;
+}
+
 static inline void red_set_parms(struct red_parms *p,
 				 u32 qth_min, u32 qth_max, u8 Wlog, u8 Plog,
 				 u8 Scell_log, u8 *stab, u32 max_P)