net/mlx4_core: Remove MCG in case it is attached to promiscuous QPs only

In B0 steering mode if promiscuous QP asks to be detached from MCG entry,
and it is the only one in this entry then the entry will never be deleted.
This is a wrong behavior since we don't want to keep those entries after
the promiscuous QP becomes non-promiscuous. Therefore remove steering
entry containing only promiscuous QP.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -270,7 +270,7 @@ static int existing_steering_entry(struct mlx4_dev *dev, u8 port,
 	 * we need to add it as a duplicate to this entry
 	 * for future references */
 	list_for_each_entry(dqp, &entry->duplicates, list) {
-		if (qpn == pqp->qpn)
+		if (qpn == dqp->qpn)
 			return 0; /* qp is already duplicated */
 	}
 
@@ -324,24 +324,22 @@ static bool check_duplicate_entry(struct mlx4_dev *dev, u8 port,
 	return true;
 }
 
-/* I a steering entry contains only promisc QPs, it can be removed. */
-static bool can_remove_steering_entry(struct mlx4_dev *dev, u8 port,
+/* Returns true if all the QPs != tqpn contained in this entry
+ * are Promisc QPs. Returns false otherwise.
+ */
+static bool promisc_steering_entry(struct mlx4_dev *dev, u8 port,
 				   enum mlx4_steer_type steer,
-				      unsigned int index, u32 tqpn)
+				   unsigned int index, u32 tqpn,
+				   u32 *members_count)
 {
-	struct mlx4_steer *s_steer;
 	struct mlx4_cmd_mailbox *mailbox;
 	struct mlx4_mgm *mgm;
-	struct mlx4_steer_index *entry = NULL, *tmp_entry;
-	u32 qpn;
-	u32 members_count;
+	u32 m_count;
 	bool ret = false;
 	int i;
 
 	if (port < 1 || port > dev->caps.num_ports)
-		return NULL;
-
-	s_steer = &mlx4_priv(dev)->steer[port - 1];
+		return false;
 
 	mailbox = mlx4_alloc_cmd_mailbox(dev);
 	if (IS_ERR(mailbox))
@@ -350,14 +348,42 @@ static bool can_remove_steering_entry(struct mlx4_dev *dev, u8 port,
 
 	if (mlx4_READ_ENTRY(dev, index, mailbox))
 		goto out;
-	members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
-	for (i = 0;  i < members_count; i++) {
-		qpn = be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK;
+	m_count = be32_to_cpu(mgm->members_count) & 0xffffff;
+	if (members_count)
+		*members_count = m_count;
+
+	for (i = 0;  i < m_count; i++) {
+		u32 qpn = be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK;
 		if (!get_promisc_qp(dev, port, steer, qpn) && qpn != tqpn) {
 			/* the qp is not promisc, the entry can't be removed */
 			goto out;
 		}
 	}
+	ret = true;
+out:
+	mlx4_free_cmd_mailbox(dev, mailbox);
+	return ret;
+}
+
+/* IF a steering entry contains only promisc QPs, it can be removed. */
+static bool can_remove_steering_entry(struct mlx4_dev *dev, u8 port,
+				      enum mlx4_steer_type steer,
+				      unsigned int index, u32 tqpn)
+{
+	struct mlx4_steer *s_steer;
+	struct mlx4_steer_index *entry = NULL, *tmp_entry;
+	u32 members_count;
+	bool ret = false;
+
+	if (port < 1 || port > dev->caps.num_ports)
+		return NULL;
+
+	s_steer = &mlx4_priv(dev)->steer[port - 1];
+
+	if (!promisc_steering_entry(dev, port, steer, index,
+				    tqpn, &members_count))
+		goto out;
+
 	/* All the qps currently registered for this entry are promiscuous,
 	  * Checking for duplicates */
 	ret = true;
@@ -387,7 +413,6 @@ static bool can_remove_steering_entry(struct mlx4_dev *dev, u8 port,
 	}
 
 out:
-	mlx4_free_cmd_mailbox(dev, mailbox);
 	return ret;
 }
 
@@ -528,7 +553,7 @@ static int remove_promisc_qp(struct mlx4_dev *dev, u8 port,
 	struct mlx4_steer *s_steer;
 	struct mlx4_cmd_mailbox *mailbox;
 	struct mlx4_mgm *mgm;
-	struct mlx4_steer_index *entry;
+	struct mlx4_steer_index *entry, *tmp_entry;
 	struct mlx4_promisc_qp *pqp;
 	struct mlx4_promisc_qp *dqp;
 	u32 members_count;
@@ -572,8 +597,8 @@ static int remove_promisc_qp(struct mlx4_dev *dev, u8 port,
 		goto out_mailbox;
 
 	if (!(mlx4_is_mfunc(dev) && steer == MLX4_UC_STEER)) {
-		/* remove the qp from all the steering entries*/
-		list_for_each_entry(entry,
+		/* Remove the QP from all the steering entries */
+		list_for_each_entry_safe(entry, tmp_entry,
 					 &s_steer->steer_entries[steer],
 					 list) {
 			found = false;
@@ -600,6 +625,14 @@ static int remove_promisc_qp(struct mlx4_dev *dev, u8 port,
 				members_count =
 					be32_to_cpu(mgm->members_count) &
 					0xffffff;
+				if (!members_count) {
+					mlx4_warn(dev, "QP %06x wasn't found in entry %x mcount=0. deleting entry...\n",
+						  qpn, entry->index);
+					list_del(&entry->list);
+					kfree(entry);
+					continue;
+				}
+
 				for (i = 0; i < members_count; ++i)
 					if ((be32_to_cpu(mgm->qp[i]) &
 					     MGM_QPN_MASK) == qpn) {
@@ -614,7 +647,7 @@ static int remove_promisc_qp(struct mlx4_dev *dev, u8 port,
 					goto out_mailbox;
 				}
 
-				/* copy the last QP in this MGM
+				/* Copy the last QP in this MGM
 				 * over removed QP
 				 */
 				mgm->qp[loc] = mgm->qp[members_count - 1];
@@ -1144,9 +1177,12 @@ int mlx4_qp_detach_common(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16],
 		goto out;
 	}
 
-	/* if this pq is also a promisc qp, it shouldn't be removed */
+	/* If this QP is also a promisc QP, it shouldn't be removed only if
+	 * at least one none promisc QP is also attached to this MCG
+	 */
 	if (prot == MLX4_PROT_ETH &&
-	    check_duplicate_entry(dev, port, steer, index, qp->qpn))
+	    check_duplicate_entry(dev, port, steer, index, qp->qpn) &&
+	    !promisc_steering_entry(dev, port, steer, index, qp->qpn, NULL))
 			goto out;
 
 	members_count = be32_to_cpu(mgm->members_count) & 0xffffff;