net/mlx4: Fix the check in attaching steering rules

Our previous patch (cited below) introduced a regression
for RAW Eth QPs.

Fix it by checking if the QP number provided by user-space
exists, hence allowing steering rules to be added for valid
QPs only.

Fixes: 89c55768 ("net/mlx4_en: Avoid adding steering rules with invalid ring")
Reported-by: Or Gerlitz <gerlitz.or@gmail.com>
Signed-off-by: Talat Batheesh <talatb@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_ethtool.c

@@ -1562,11 +1562,6 @@ static int mlx4_en_flow_replace(struct net_device *dev,
 		qpn = priv->drop_qp.qpn;
 	else if (cmd->fs.ring_cookie & EN_ETHTOOL_QP_ATTACH) {
 		qpn = cmd->fs.ring_cookie & (EN_ETHTOOL_QP_ATTACH - 1);
-		if (qpn < priv->rss_map.base_qpn ||
-		    qpn >= priv->rss_map.base_qpn + priv->rx_ring_num) {
-			en_warn(priv, "rxnfc: QP (0x%x) doesn't exist\n", qpn);
-			return -EINVAL;
-		}
 	} else {
 		if (cmd->fs.ring_cookie >= priv->rx_ring_num) {
 			en_warn(priv, "rxnfc: RX ring (%llu) doesn't exist\n",

drivers/net/ethernet/mellanox/mlx4/mcg.c

@@ -35,6 +35,7 @@
 #include <linux/etherdevice.h>
 
 #include <linux/mlx4/cmd.h>
+#include <linux/mlx4/qp.h>
 #include <linux/export.h>
 
 #include "mlx4.h"
@@ -985,16 +986,21 @@ int mlx4_flow_attach(struct mlx4_dev *dev,
 	if (IS_ERR(mailbox))
 		return PTR_ERR(mailbox);
 
+	if (!mlx4_qp_lookup(dev, rule->qpn)) {
+		mlx4_err_rule(dev, "QP doesn't exist\n", rule);
+		ret = -EINVAL;
+		goto out;
+	}
+
 	trans_rule_ctrl_to_hw(rule, mailbox->buf);
 
 	size += sizeof(struct mlx4_net_trans_rule_hw_ctrl);
 
 	list_for_each_entry(cur, &rule->list, list) {
 		ret = parse_trans_rule(dev, cur, mailbox->buf + size);
-		if (ret < 0) {
-			mlx4_free_cmd_mailbox(dev, mailbox);
-			return ret;
-		}
+		if (ret < 0)
+			goto out;
+
 		size += ret;
 	}
 
@@ -1021,6 +1027,7 @@ int mlx4_flow_attach(struct mlx4_dev *dev,
 		}
 	}
 
+out:
 	mlx4_free_cmd_mailbox(dev, mailbox);
 
 	return ret;

drivers/net/ethernet/mellanox/mlx4/qp.c

@@ -384,6 +384,19 @@ static void mlx4_qp_free_icm(struct mlx4_dev *dev, int qpn)
 		__mlx4_qp_free_icm(dev, qpn);
 }
 
+struct mlx4_qp *mlx4_qp_lookup(struct mlx4_dev *dev, u32 qpn)
+{
+	struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table;
+	struct mlx4_qp *qp;
+
+	spin_lock(&qp_table->lock);
+
+	qp = __mlx4_qp_lookup(dev, qpn);
+
+	spin_unlock(&qp_table->lock);
+	return qp;
+}
+
 int mlx4_qp_alloc(struct mlx4_dev *dev, int qpn, struct mlx4_qp *qp, gfp_t gfp)
 {
 	struct mlx4_priv *priv = mlx4_priv(dev);

include/linux/mlx4/qp.h

@@ -470,6 +470,7 @@ struct mlx4_update_qp_params {
 	u16	rate_val;
 };
 
+struct mlx4_qp *mlx4_qp_lookup(struct mlx4_dev *dev, u32 qpn);
 int mlx4_update_qp(struct mlx4_dev *dev, u32 qpn,
 		   enum mlx4_update_qp_attr attr,
 		   struct mlx4_update_qp_params *params);