Merge branch 'dsa-bridge-tx-forwarding-offload-fixes-part-1'

Vladimir Oltean says:

====================
DSA bridge TX forwarding offload fixes - part 1

This is part 1 of a series of fixes to the bridge TX forwarding offload
feature introduced for v5.15. Sadly, the other fixes are so intrusive
that they cannot be reasonably be sent to the "net" tree, as they also
include API changes. So they are left as part 2 for net-next.
====================

Link: https://lore.kernel.org/r/20211007164711.2897238-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 10 insertions, 20 deletions

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index b29262eee00b..6d5cc0217133 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -170,7 +170,7 @@ void dsa_bridge_num_put(const struct net_device *bridge_dev, int bridge_num)
 	/* Check if the bridge is still in use, otherwise it is time
 	 * to clean it up so we can reuse this bridge_num later.
 	 */
-	if (!dsa_bridge_num_find(bridge_dev))
+	if (dsa_bridge_num_find(bridge_dev) < 0)
 		clear_bit(bridge_num, &dsa_fwd_offloading_bridges);
 }
 
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index e5127b7d1c6a..b3da4b2ea11c 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -45,6 +45,7 @@
  *   6    6       2        2      4    2       N
  */
 
+#include <linux/dsa/mv88e6xxx.h>
 #include <linux/etherdevice.h>
 #include <linux/list.h>
 #include <linux/slab.h>
@@ -129,12 +130,9 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 	u8 tag_dev, tag_port;
 	enum dsa_cmd cmd;
 	u8 *dsa_header;
-	u16 pvid = 0;
-	int err;
 
 	if (skb->offload_fwd_mark) {
 		struct dsa_switch_tree *dst = dp->ds->dst;
-		struct net_device *br = dp->bridge_dev;
 
 		cmd = DSA_CMD_FORWARD;
 
@@ -144,19 +142,6 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 		 */
 		tag_dev = dst->last_switch + 1 + dp->bridge_num;
 		tag_port = 0;
-
-		/* If we are offloading forwarding for a VLAN-unaware bridge,
-		 * inject packets to hardware using the bridge's pvid, since
-		 * that's where the packets ingressed from.
-		 */
-		if (!br_vlan_enabled(br)) {
-			/* Safe because __dev_queue_xmit() runs under
-			 * rcu_read_lock_bh()
-			 */
-			err = br_vlan_get_pvid_rcu(br, &pvid);
-			if (err)
-				return NULL;
-		}
 	} else {
 		cmd = DSA_CMD_FROM_CPU;
 		tag_dev = dp->ds->index;
@@ -180,16 +165,21 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 			dsa_header[2] &= ~0x10;
 		}
 	} else {
+		struct net_device *br = dp->bridge_dev;
+		u16 vid;
+
+		vid = br ? MV88E6XXX_VID_BRIDGED : MV88E6XXX_VID_STANDALONE;
+
 		skb_push(skb, DSA_HLEN + extra);
 		dsa_alloc_etype_header(skb, DSA_HLEN + extra);
 
-		/* Construct untagged DSA tag. */
+		/* Construct DSA header from untagged frame. */
 		dsa_header = dsa_etype_header_pos_tx(skb) + extra;
 
 		dsa_header[0] = (cmd << 6) | tag_dev;
 		dsa_header[1] = tag_port << 3;
-		dsa_header[2] = pvid >> 8;
-		dsa_header[3] = pvid & 0xff;
+		dsa_header[2] = vid >> 8;
+		dsa_header[3] = vid & 0xff;
 	}
 
 	return skb;