[net-next, v4 06/10] bnge: remove refcount from L2 filter

[Vikas Gupta]

A reference count was previously used under the assumption that any
context holding the last reference could delete the L2 filter.

However, going forward, the filter will only be removed by the same
context that created it, making refcount unnecessary.

Signed-off-by: Vikas Gupta <vikas.gupta@xxxxxxxxxxxx>
Reviewed-by: Dharmender Garg <dharmender.garg@xxxxxxxxxxxx>
---
 .../net/ethernet/broadcom/bnge/bnge_filter.c  | 28 ++++---------------
 .../net/ethernet/broadcom/bnge/bnge_filter.h  |  1 -
 .../net/ethernet/broadcom/bnge/bnge_netdev.c  | 23 +++++++++++----
 3 files changed, 23 insertions(+), 29 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnge/bnge_filter.c b/drivers/net/ethernet/broadcom/bnge/bnge_filter.c
index a8bb441ebef9..3b26939b0457 100644
--- a/drivers/net/ethernet/broadcom/bnge/bnge_filter.c
+++ b/drivers/net/ethernet/broadcom/bnge/bnge_filter.c
@@ -13,8 +13,6 @@
 
 void bnge_del_l2_filter(struct bnge_net *bn, struct bnge_l2_filter *fltr)
 {
-	if (!refcount_dec_and_test(&fltr->refcnt))
-		return;
 	hlist_del_rcu(&fltr->base.hlist);
 	kfree_rcu(fltr, base.rcu);
 }
@@ -31,18 +29,17 @@ static void bnge_init_l2_filter(struct bnge_net *bn,
 
 	head = &bn->l2_fltr_hash_tbl[idx];
 	hlist_add_head_rcu(&fltr->base.hlist, head);
-	refcount_set(&fltr->refcnt, 1);
 }
 
-static struct bnge_l2_filter *__bnge_lookup_l2_filter(struct bnge_net *bn,
-						      struct bnge_l2_key *key,
-						      u32 idx)
+static struct bnge_l2_filter *bnge_lookup_l2_filter(struct bnge_net *bn,
+						    struct bnge_l2_key *key,
+						    u32 idx)
 {
 	struct bnge_l2_filter *fltr;
 	struct hlist_head *head;
 
 	head = &bn->l2_fltr_hash_tbl[idx];
-	hlist_for_each_entry_rcu(fltr, head, base.hlist) {
+	hlist_for_each_entry(fltr, head, base.hlist) {
 		struct bnge_l2_key *l2_key = &fltr->l2_key;
 
 		if (ether_addr_equal(l2_key->dst_mac_addr, key->dst_mac_addr) &&
@@ -52,20 +49,6 @@ static struct bnge_l2_filter *__bnge_lookup_l2_filter(struct bnge_net *bn,
 	return NULL;
 }
 
-static struct bnge_l2_filter *bnge_lookup_l2_filter(struct bnge_net *bn,
-						    struct bnge_l2_key *key,
-						    u32 idx)
-{
-	struct bnge_l2_filter *fltr;
-
-	rcu_read_lock();
-	fltr = __bnge_lookup_l2_filter(bn, key, idx);
-	if (fltr)
-		refcount_inc(&fltr->refcnt);
-	rcu_read_unlock();
-	return fltr;
-}
-
 static struct bnge_l2_filter *bnge_alloc_l2_filter(struct bnge_net *bn,
 						   struct bnge_l2_key *key,
 						   gfp_t gfp)
@@ -75,9 +58,10 @@ static struct bnge_l2_filter *bnge_alloc_l2_filter(struct bnge_net *bn,
 
 	idx = jhash2(&key->filter_key, BNGE_L2_KEY_SIZE, bn->hash_seed) &
 	      BNGE_L2_FLTR_HASH_MASK;
+
 	fltr = bnge_lookup_l2_filter(bn, key, idx);
 	if (fltr)
-		return fltr;
+		return ERR_PTR(-EEXIST);
 
 	fltr = kzalloc_obj(*fltr, gfp);
 	if (!fltr)
diff --git a/drivers/net/ethernet/broadcom/bnge/bnge_filter.h b/drivers/net/ethernet/broadcom/bnge/bnge_filter.h
index ea1acefd70b4..a4a386202ac3 100644
--- a/drivers/net/ethernet/broadcom/bnge/bnge_filter.h
+++ b/drivers/net/ethernet/broadcom/bnge/bnge_filter.h
@@ -49,7 +49,6 @@ struct bnge_l2_filter {
 	/* base filter must be the first member */
 	struct bnge_filter_base	base;
 	struct bnge_l2_key	l2_key;
-	refcount_t		refcnt;
 };
 
 void bnge_del_l2_filter(struct bnge_net *bn, struct bnge_l2_filter *fltr);
diff --git a/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c b/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c
index ac77ba813f01..29a271f50e04 100644
--- a/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c
+++ b/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c
@@ -2011,19 +2011,24 @@ static bool bnge_uc_list_updated(struct bnge_net *bn,
 				 const struct netdev_hw_addr_list *uc)
 {
 	struct bnge_vnic_info *vnic = &bn->vnic_info[BNGE_VNIC_DEFAULT];
+	struct net_device *dev = bn->netdev;
 	struct netdev_hw_addr *ha;
-	int off = 0;
-
-	if (netdev_hw_addr_list_count(uc) != (vnic->uc_filter_count - 1))
-		return true;
+	int off = 0, count = 0;
 
+	/* dev_addr is installed as L2 filter 0 and skipped when building
+	 * uc_list, so compare only the unicast entries that differ from it.
+	 */
 	netdev_hw_addr_list_for_each(ha, uc) {
+		if (ether_addr_equal(ha->addr, dev->dev_addr))
+			continue;
+		if (count >= vnic->uc_filter_count - 1)
+			return true;
 		if (!ether_addr_equal(ha->addr, vnic->uc_list + off))
 			return true;
-
 		off += ETH_ALEN;
+		count++;
 	}
-	return false;
+	return count != vnic->uc_filter_count - 1;
 }
 
 static bool bnge_promisc_ok(struct bnge_net *bn)
@@ -2058,6 +2063,12 @@ static int bnge_cfg_rx_mode(struct bnge_net *bn, struct netdev_hw_addr_list *uc,
 		vnic->rx_mask |= CFA_L2_SET_RX_MASK_REQ_MASK_PROMISCUOUS;
 	} else {
 		netdev_hw_addr_list_for_each(ha, uc) {
+			/* dev_addr is already installed as L2 filter 0; a uc
+			 * entry equal to it hashes to the same key and would be
+			 * rejected as a duplicate, so skip it here.
+			 */
+			if (ether_addr_equal(ha->addr, dev->dev_addr))
+				continue;
 			memcpy(vnic->uc_list + off, ha->addr, ETH_ALEN);
 			off += ETH_ALEN;
 			vnic->uc_filter_count++;
-- 
2.52.0