Merge branch 'Traffic-support-for-dsa_8021q-in-vlan_filtering-1-mode'

Vladimir Oltean says:

====================
Traffic support for dsa_8021q in vlan_filtering=1 mode

This series is an attempt to support as much as possible in terms of
traffic I/O from the network stack with the only dsa_8021q user thus
far, sja1105.

The hardware doesn't support pushing a second VLAN tag to packets that
are already tagged, so our only option is to combine the dsa_8021q with
the user tag into a single tag and decode that on the CPU.

The assumption is that there is a type of use cases for which 7 VLANs
per port are more than sufficient, and that there's another type of use
cases where the full 4096 entries are barely enough. Those use cases are
very different from one another, so I prefer trying to give both the
best experience by creating this best_effort_vlan_filtering knob to
select the mode in which they want to operate in.

v2 was submitted here:
https://patchwork.ozlabs.org/project/netdev/cover/20200511135338.20263-1-olteanv@gmail.com/

v1 was submitted here:
https://patchwork.ozlabs.org/project/netdev/cover/20200510164255.19322-1-olteanv@gmail.com/

Changes in v3:
Patch 01/15:
- Rename again to configure_vlan_while_not_filtering, and add a helper
  function for skipping VLAN configuration.
Patch 03/15:
- Remove sja1105_can_use_vlan_as_tags from driver code.
Patch 06/15:
- Adapt sja1105 driver to the second variable name change.
Patch 08/15:
- Provide an implementation of sja1105_can_use_vlan_as_tags as part of
  the tagger and not as part of the switch driver. So we have to look at
  the skb only, and not at the VLAN awareness state.

Changes in v2:
Patch 01/15:
- Rename variable from vlan_bridge_vtu to configure_vlans_while_disabled.
Patch 03/15:
- Be much more thorough, and make sure that things like virtual links
  and FDB operations still work properly.
Patch 05/15:
- Free the vlan lists on teardown.
- Simplify sja1105_classify_vlan: only look at priv->expect_dsa_8021q.
- Keep vid 1 in the list of dsa_8021q VLANs, to make sure that untagged
  packets transmitted from the stack, like PTP, continue to work in
  VLAN-unaware mode.
Patch 06/15:
- Adapt to vlan_bridge_vtu variable name change.
Patch 11/15:
- In sja1105_best_effort_vlan_filtering_set, get the vlan_filtering
  value of each port instead of just one time for port 0. Normally this
  shouldn't matter, but it avoids issues when port 0 is disabled in
  device tree.
Patch 14/14:
- Only do anything in sja1105_build_subvlans and in
  sja1105_build_crosschip_subvlans when operating in
  SJA1105_VLAN_BEST_EFFORT state. This avoids installing VLAN retagging
  rules in unaware mode, which would cost us a penalty in terms of
  usable frame memory.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 131 insertions, 51 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index a1a0ae242012..adecf73bd608 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -138,6 +138,7 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br);
 void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br);
 int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
 			    struct switchdev_trans *trans);
+bool dsa_port_skip_vlan_configuration(struct dsa_port *dp);
 int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock,
 			 struct switchdev_trans *trans);
 int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu,
diff --git a/net/dsa/port.c b/net/dsa/port.c
index ebc8d6cbd1d4..e23ece229c7e 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -257,6 +257,20 @@ int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
 	return 0;
 }
 
+/* This enforces legacy behavior for switch drivers which assume they can't
+ * receive VLAN configuration when enslaved to a bridge with vlan_filtering=0
+ */
+bool dsa_port_skip_vlan_configuration(struct dsa_port *dp)
+{
+	struct dsa_switch *ds = dp->ds;
+
+	if (!dp->bridge_dev)
+		return false;
+
+	return (!ds->configure_vlan_while_not_filtering &&
+		!br_vlan_enabled(dp->bridge_dev));
+}
+
 int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock,
 			 struct switchdev_trans *trans)
 {
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 61b0de52040a..886490fb203d 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -314,7 +314,7 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 	if (obj->orig_dev != dev)
 		return -EOPNOTSUPP;
 
-	if (dp->bridge_dev && !br_vlan_enabled(dp->bridge_dev))
+	if (dsa_port_skip_vlan_configuration(dp))
 		return 0;
 
 	vlan = *SWITCHDEV_OBJ_PORT_VLAN(obj);
@@ -381,7 +381,7 @@ static int dsa_slave_vlan_del(struct net_device *dev,
 	if (obj->orig_dev != dev)
 		return -EOPNOTSUPP;
 
-	if (dp->bridge_dev && !br_vlan_enabled(dp->bridge_dev))
+	if (dsa_port_skip_vlan_configuration(dp))
 		return 0;
 
 	/* Do not deprogram the CPU port as it may be shared with other user
@@ -1240,7 +1240,7 @@ static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 	 * need to emulate the switchdev prepare + commit phase.
 	 */
 	if (dp->bridge_dev) {
-		if (!br_vlan_enabled(dp->bridge_dev))
+		if (dsa_port_skip_vlan_configuration(dp))
 			return 0;
 
 		/* br_vlan_get_info() returns -EINVAL or -ENOENT if the
@@ -1274,7 +1274,7 @@ static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
 	 * need to emulate the switchdev prepare + commit phase.
 	 */
 	if (dp->bridge_dev) {
-		if (!br_vlan_enabled(dp->bridge_dev))
+		if (dsa_port_skip_vlan_configuration(dp))
 			return 0;
 
 		/* br_vlan_get_info() returns -EINVAL or -ENOENT if the
diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index ff9c5bf64bda..3052da668156 100644
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -17,7 +17,7 @@
  *
  * | 11  | 10  |  9  |  8  |  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |
  * +-----------+-----+-----------------+-----------+-----------------------+
- * |    DIR    | RSV |    SWITCH_ID    |    RSV    |          PORT         |
+ * |    DIR    | SVL |    SWITCH_ID    |  SUBVLAN  |          PORT         |
  * +-----------+-----+-----------------+-----------+-----------------------+
  *
  * DIR - VID[11:10]:
@@ -27,17 +27,24 @@
  *	These values make the special VIDs of 0, 1 and 4095 to be left
  *	unused by this coding scheme.
  *
- * RSV - VID[9]:
- *	To be used for further expansion of SWITCH_ID or for other purposes.
- *	Must be transmitted as zero and ignored on receive.
+ * SVL/SUBVLAN - { VID[9], VID[5:4] }:
+ *	Sub-VLAN encoding. Valid only when DIR indicates an RX VLAN.
+ *	* 0 (0b000): Field does not encode a sub-VLAN, either because
+ *	received traffic is untagged, PVID-tagged or because a second
+ *	VLAN tag is present after this tag and not inside of it.
+ *	* 1 (0b001): Received traffic is tagged with a VID value private
+ *	to the host. This field encodes the index in the host's lookup
+ *	table through which the value of the ingress VLAN ID can be
+ *	recovered.
+ *	* 2 (0b010): Field encodes a sub-VLAN.
+ *	...
+ *	* 7 (0b111): Field encodes a sub-VLAN.
+ *	When DIR indicates a TX VLAN, SUBVLAN must be transmitted as zero
+ *	(by the host) and ignored on receive (by the switch).
  *
  * SWITCH_ID - VID[8:6]:
  *	Index of switch within DSA tree. Must be between 0 and 7.
  *
- * RSV - VID[5:4]:
- *	To be used for further expansion of PORT or for other purposes.
- *	Must be transmitted as zero and ignored on receive.
- *
  * PORT - VID[3:0]:
  *	Index of switch port. Must be between 0 and 15.
  */
@@ -54,6 +61,18 @@
 #define DSA_8021Q_SWITCH_ID(x)		(((x) << DSA_8021Q_SWITCH_ID_SHIFT) & \
 						 DSA_8021Q_SWITCH_ID_MASK)
 
+#define DSA_8021Q_SUBVLAN_HI_SHIFT	9
+#define DSA_8021Q_SUBVLAN_HI_MASK	GENMASK(9, 9)
+#define DSA_8021Q_SUBVLAN_LO_SHIFT	4
+#define DSA_8021Q_SUBVLAN_LO_MASK	GENMASK(4, 3)
+#define DSA_8021Q_SUBVLAN_HI(x)		(((x) & GENMASK(2, 2)) >> 2)
+#define DSA_8021Q_SUBVLAN_LO(x)		((x) & GENMASK(1, 0))
+#define DSA_8021Q_SUBVLAN(x)		\
+		(((DSA_8021Q_SUBVLAN_LO(x) << DSA_8021Q_SUBVLAN_LO_SHIFT) & \
+		  DSA_8021Q_SUBVLAN_LO_MASK) | \
+		 ((DSA_8021Q_SUBVLAN_HI(x) << DSA_8021Q_SUBVLAN_HI_SHIFT) & \
+		  DSA_8021Q_SUBVLAN_HI_MASK))
+
 #define DSA_8021Q_PORT_SHIFT		0
 #define DSA_8021Q_PORT_MASK		GENMASK(3, 0)
 #define DSA_8021Q_PORT(x)		(((x) << DSA_8021Q_PORT_SHIFT) & \
@@ -79,6 +98,13 @@ u16 dsa_8021q_rx_vid(struct dsa_switch *ds, int port)
 }
 EXPORT_SYMBOL_GPL(dsa_8021q_rx_vid);
 
+u16 dsa_8021q_rx_vid_subvlan(struct dsa_switch *ds, int port, u16 subvlan)
+{
+	return DSA_8021Q_DIR_RX | DSA_8021Q_SWITCH_ID(ds->index) |
+	       DSA_8021Q_PORT(port) | DSA_8021Q_SUBVLAN(subvlan);
+}
+EXPORT_SYMBOL_GPL(dsa_8021q_rx_vid_subvlan);
+
 /* Returns the decoded switch ID from the RX VID. */
 int dsa_8021q_rx_switch_id(u16 vid)
 {
@@ -93,6 +119,27 @@ int dsa_8021q_rx_source_port(u16 vid)
 }
 EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port);
 
+/* Returns the decoded subvlan from the RX VID. */
+u16 dsa_8021q_rx_subvlan(u16 vid)
+{
+	u16 svl_hi, svl_lo;
+
+	svl_hi = (vid & DSA_8021Q_SUBVLAN_HI_MASK) >>
+		 DSA_8021Q_SUBVLAN_HI_SHIFT;
+	svl_lo = (vid & DSA_8021Q_SUBVLAN_LO_MASK) >>
+		 DSA_8021Q_SUBVLAN_LO_SHIFT;
+
+	return (svl_hi << 2) | svl_lo;
+}
+EXPORT_SYMBOL_GPL(dsa_8021q_rx_subvlan);
+
+bool vid_is_dsa_8021q(u16 vid)
+{
+	return ((vid & DSA_8021Q_DIR_MASK) == DSA_8021Q_DIR_RX ||
+		(vid & DSA_8021Q_DIR_MASK) == DSA_8021Q_DIR_TX);
+}
+EXPORT_SYMBOL_GPL(vid_is_dsa_8021q);
+
 static int dsa_8021q_restore_pvid(struct dsa_switch *ds, int port)
 {
 	struct bridge_vlan_info vinfo;
@@ -289,9 +336,9 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
 }
 EXPORT_SYMBOL_GPL(dsa_port_setup_8021q_tagging);
 
-int dsa_8021q_crosschip_link_apply(struct dsa_switch *ds, int port,
-				   struct dsa_switch *other_ds,
-				   int other_port, bool enabled)
+static int dsa_8021q_crosschip_link_apply(struct dsa_switch *ds, int port,
+					  struct dsa_switch *other_ds,
+					  int other_port, bool enabled)
 {
 	u16 rx_vid = dsa_8021q_rx_vid(ds, port);
 
@@ -301,7 +348,6 @@ int dsa_8021q_crosschip_link_apply(struct dsa_switch *ds, int port,
 	return dsa_8021q_vid_apply(other_ds, other_port, rx_vid,
 				   BRIDGE_VLAN_INFO_UNTAGGED, enabled);
 }
-EXPORT_SYMBOL_GPL(dsa_8021q_crosschip_link_apply);
 
 static int dsa_8021q_crosschip_link_add(struct dsa_switch *ds, int port,
 					struct dsa_switch *other_ds,
@@ -362,7 +408,7 @@ static void dsa_8021q_crosschip_link_del(struct dsa_switch *ds,
  */
 int dsa_8021q_crosschip_bridge_join(struct dsa_switch *ds, int port,
 				    struct dsa_switch *other_ds,
-				    int other_port, struct net_device *br,
+				    int other_port,
 				    struct list_head *crosschip_links)
 {
 	/* @other_upstream is how @other_ds reaches us. If we are part
@@ -378,12 +424,10 @@ int dsa_8021q_crosschip_bridge_join(struct dsa_switch *ds, int port,
 	if (rc)
 		return rc;
 
-	if (!br_vlan_enabled(br)) {
-		rc = dsa_8021q_crosschip_link_apply(ds, port, other_ds,
-						    other_port, true);
-		if (rc)
-			return rc;
-	}
+	rc = dsa_8021q_crosschip_link_apply(ds, port, other_ds,
+					    other_port, true);
+	if (rc)
+		return rc;
 
 	rc = dsa_8021q_crosschip_link_add(ds, port, other_ds,
 					  other_upstream,
@@ -391,20 +435,14 @@ int dsa_8021q_crosschip_bridge_join(struct dsa_switch *ds, int port,
 	if (rc)
 		return rc;
 
-	if (!br_vlan_enabled(br)) {
-		rc = dsa_8021q_crosschip_link_apply(ds, port, other_ds,
-						    other_upstream, true);
-		if (rc)
-			return rc;
-	}
-
-	return 0;
+	return dsa_8021q_crosschip_link_apply(ds, port, other_ds,
+					      other_upstream, true);
 }
 EXPORT_SYMBOL_GPL(dsa_8021q_crosschip_bridge_join);
 
 int dsa_8021q_crosschip_bridge_leave(struct dsa_switch *ds, int port,
 				     struct dsa_switch *other_ds,
-				     int other_port, struct net_device *br,
+				     int other_port,
 				     struct list_head *crosschip_links)
 {
 	int other_upstream = dsa_upstream_port(other_ds, other_port);
@@ -424,14 +462,12 @@ int dsa_8021q_crosschip_bridge_leave(struct dsa_switch *ds, int port,
 			if (keep)
 				continue;
 
-			if (!br_vlan_enabled(br)) {
-				rc = dsa_8021q_crosschip_link_apply(ds, port,
-								    other_ds,
-								    other_port,
-								    false);
-				if (rc)
-					return rc;
-			}
+			rc = dsa_8021q_crosschip_link_apply(ds, port,
+							    other_ds,
+							    other_port,
+							    false);
+			if (rc)
+				return rc;
 		}
 	}
 
diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index 5ecac5921a7d..ad105550b145 100644
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -69,12 +69,25 @@ static inline bool sja1105_is_meta_frame(const struct sk_buff *skb)
 	return true;
 }
 
+static bool sja1105_can_use_vlan_as_tags(const struct sk_buff *skb)
+{
+	struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+
+	if (hdr->h_vlan_proto == ntohs(ETH_P_SJA1105))
+		return true;
+
+	if (hdr->h_vlan_proto != ntohs(ETH_P_8021Q))
+		return false;
+
+	return vid_is_dsa_8021q(ntohs(hdr->h_vlan_TCI) & VLAN_VID_MASK);
+}
+
 /* This is the first time the tagger sees the frame on RX.
  * Figure out if we can decode it.
  */
 static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev)
 {
-	if (!dsa_port_is_vlan_filtering(dev->dsa_ptr))
+	if (sja1105_can_use_vlan_as_tags(skb))
 		return true;
 	if (sja1105_is_link_local(skb))
 		return true;
@@ -96,6 +109,11 @@ static struct sk_buff *sja1105_defer_xmit(struct sja1105_port *sp,
 	return NULL;
 }
 
+static u16 sja1105_xmit_tpid(struct sja1105_port *sp)
+{
+	return sp->xmit_tpid;
+}
+
 static struct sk_buff *sja1105_xmit(struct sk_buff *skb,
 				    struct net_device *netdev)
 {
@@ -111,15 +129,7 @@ static struct sk_buff *sja1105_xmit(struct sk_buff *skb,
 	if (unlikely(sja1105_is_link_local(skb)))
 		return sja1105_defer_xmit(dp->priv, skb);
 
-	/* If we are under a vlan_filtering bridge, IP termination on
-	 * switch ports based on 802.1Q tags is simply too brittle to
-	 * be passable. So just defer to the dsa_slave_notag_xmit
-	 * implementation.
-	 */
-	if (dsa_port_is_vlan_filtering(dp))
-		return skb;
-
-	return dsa_8021q_xmit(skb, netdev, ETH_P_SJA1105,
+	return dsa_8021q_xmit(skb, netdev, sja1105_xmit_tpid(dp->priv),
 			     ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
 }
 
@@ -244,6 +254,20 @@ static struct sk_buff
 	return skb;
 }
 
+static void sja1105_decode_subvlan(struct sk_buff *skb, u16 subvlan)
+{
+	struct dsa_port *dp = dsa_slave_to_port(skb->dev);
+	struct sja1105_port *sp = dp->priv;
+	u16 vid = sp->subvlan_map[subvlan];
+	u16 vlan_tci;
+
+	if (vid == VLAN_N_VID)
+		return;
+
+	vlan_tci = (skb->priority << VLAN_PRIO_SHIFT) | vid;
+	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tci);
+}
+
 static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 				   struct net_device *netdev,
 				   struct packet_type *pt)
@@ -253,12 +277,13 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 	struct ethhdr *hdr;
 	u16 tpid, vid, tci;
 	bool is_link_local;
+	u16 subvlan = 0;
 	bool is_tagged;
 	bool is_meta;
 
 	hdr = eth_hdr(skb);
 	tpid = ntohs(hdr->h_proto);
-	is_tagged = (tpid == ETH_P_SJA1105);
+	is_tagged = (tpid == ETH_P_SJA1105 || tpid == ETH_P_8021Q);
 	is_link_local = sja1105_is_link_local(skb);
 	is_meta = sja1105_is_meta_frame(skb);
 
@@ -276,6 +301,7 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 		source_port = dsa_8021q_rx_source_port(vid);
 		switch_id = dsa_8021q_rx_switch_id(vid);
 		skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
+		subvlan = dsa_8021q_rx_subvlan(vid);
 	} else if (is_link_local) {
 		/* Management traffic path. Switch embeds the switch ID and
 		 * port ID into bytes of the destination MAC, courtesy of
@@ -300,6 +326,9 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 		return NULL;
 	}
 
+	if (subvlan)
+		sja1105_decode_subvlan(skb, subvlan);
+
 	return sja1105_rcv_meta_state_machine(skb, &meta, is_link_local,
 					      is_meta);
 }