[PATCH net-next 0/5] net: dsa: mv88e6xxx: avoid some redundant VTU operations

[PATCH net-next 0/5] net: dsa: mv88e6xxx: avoid some redundant VTU operations

[Vivien Didelot]

The mv88e6xxx driver currently uses a mv88e6xxx_vtu_get wrapper to get a
single entry and uses a boolean to eventually initialize a fresh one.

However the fresh entry is only needed in one place and mv88e6xxx_vtu_getnext
is simple enough to call it directly. Doing so makes the code easier to read,
especially for the return code expected by switchdev to honor software VLANs.

In addition to not loading the VTU again when an entry is already correctly
programmed, this also allows to avoid programming the broadcast entries
again when updating a port's membership, from e.g. tagged to untagged.

This patch series removes the mv88e6xxx_vtu_get wrapper in favor of direct
calls to mv88e6xxx_vtu_getnext, and also renames the _mv88e6xxx_port_vlan_add
and _mv88e6xxx_port_vlan_del helpers using an old underscore prefix convention.

In case the port's membership is already correctly programmed in hardware,
the following debug message may be printed:

    [  745.989884] mv88e6085 2188000.ethernet-1:00: p4: already a member of VLAN 42

Vivien Didelot (5):
  net: dsa: mv88e6xxx: lock mutex in vlan_prepare
  net: dsa: mv88e6xxx: explicit entry passed to vtu_getnext
  net: dsa: mv88e6xxx: call vtu_getnext directly in db load/purge
  net: dsa: mv88e6xxx: call vtu_getnext directly in vlan_del
  net: dsa: mv88e6xxx: call vtu_getnext directly in vlan_add

 drivers/net/dsa/mv88e6xxx/chip.c | 182 +++++++++++++++++--------------
 1 file changed, 98 insertions(+), 84 deletions(-)

-- 
2.22.0

[PATCH net-next 1/5] net: dsa: mv88e6xxx: lock mutex in vlan_prepare

[Vivien Didelot]

Lock the mutex in the mv88e6xxx_port_vlan_prepare function
called by the DSA stack, instead of doing it in the internal
mv88e6xxx_port_check_hw_vlan helper.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 2e500428670c..1b2cb46d3b53 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1453,12 +1453,10 @@ static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 	if (!vid_begin)
 		return -EOPNOTSUPP;
 
-	mv88e6xxx_reg_lock(chip);
-
 	do {
 		err = mv88e6xxx_vtu_getnext(chip, &vlan);
 		if (err)
-			goto unlock;
+			return err;
 
 		if (!vlan.valid)
 			break;
@@ -1487,15 +1485,11 @@ static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 			dev_err(ds->dev, "p%d: hw VLAN %d already used by port %d in %s\n",
 				port, vlan.vid, i,
 				netdev_name(dsa_to_port(ds, i)->bridge_dev));
-			err = -EOPNOTSUPP;
-			goto unlock;
+			return -EOPNOTSUPP;
 		}
 	} while (vlan.vid < vid_end);
 
-unlock:
-	mv88e6xxx_reg_unlock(chip);
-
-	return err;
+	return 0;
 }
 
 static int mv88e6xxx_port_vlan_filtering(struct dsa_switch *ds, int port,
@@ -1529,15 +1523,15 @@ mv88e6xxx_port_vlan_prepare(struct dsa_switch *ds, int port,
 	/* If the requested port doesn't belong to the same bridge as the VLAN
 	 * members, do not support it (yet) and fallback to software VLAN.
 	 */
+	mv88e6xxx_reg_lock(chip);
 	err = mv88e6xxx_port_check_hw_vlan(ds, port, vlan->vid_begin,
 					   vlan->vid_end);
-	if (err)
-		return err;
+	mv88e6xxx_reg_unlock(chip);
 
 	/* We don't need any dynamic resource from the kernel (yet),
 	 * so skip the prepare phase.
 	 */
-	return 0;
+	return err;
 }
 
 static int mv88e6xxx_port_db_load_purge(struct mv88e6xxx_chip *chip, int port,
-- 
2.22.0

[PATCH net-next 2/5] net: dsa: mv88e6xxx: explicit entry passed to vtu_getnext

[Vivien Didelot]

mv88e6xxx_vtu_getnext interprets two members from the input
mv88e6xxx_vtu_entry structure: the (excluded) vid member to start
the iteration from, and the valid argument specifying whether the VID
must be written or not (only required once at the start of a loop).

Explicit the assignation of these two fields right before calling
mv88e6xxx_vtu_getnext, as it is done in the mv88e6xxx_vtu_get wrapper.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 1b2cb46d3b53..c825fa3477fa 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1361,9 +1361,7 @@ static int mv88e6xxx_vtu_loadpurge(struct mv88e6xxx_chip *chip,
 static int mv88e6xxx_atu_new(struct mv88e6xxx_chip *chip, u16 *fid)
 {
 	DECLARE_BITMAP(fid_bitmap, MV88E6XXX_N_FID);
-	struct mv88e6xxx_vtu_entry vlan = {
-		.vid = chip->info->max_vid,
-	};
+	struct mv88e6xxx_vtu_entry vlan;
 	int i, err;
 
 	bitmap_zero(fid_bitmap, MV88E6XXX_N_FID);
@@ -1378,6 +1376,9 @@ static int mv88e6xxx_atu_new(struct mv88e6xxx_chip *chip, u16 *fid)
 	}
 
 	/* Set every FID bit used by the VLAN entries */
+	vlan.vid = chip->info->max_vid;
+	vlan.valid = false;
+
 	do {
 		err = mv88e6xxx_vtu_getnext(chip, &vlan);
 		if (err)
@@ -1441,9 +1442,7 @@ static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 					u16 vid_begin, u16 vid_end)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
-	struct mv88e6xxx_vtu_entry vlan = {
-		.vid = vid_begin - 1,
-	};
+	struct mv88e6xxx_vtu_entry vlan;
 	int i, err;
 
 	/* DSA and CPU ports have to be members of multiple vlans */
@@ -1453,6 +1452,9 @@ static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 	if (!vid_begin)
 		return -EOPNOTSUPP;
 
+	vlan.vid = vid_begin - 1;
+	vlan.valid = false;
+
 	do {
 		err = mv88e6xxx_vtu_getnext(chip, &vlan);
 		if (err)
@@ -1789,9 +1791,7 @@ static int mv88e6xxx_port_db_dump_fid(struct mv88e6xxx_chip *chip,
 static int mv88e6xxx_port_db_dump(struct mv88e6xxx_chip *chip, int port,
 				  dsa_fdb_dump_cb_t *cb, void *data)
 {
-	struct mv88e6xxx_vtu_entry vlan = {
-		.vid = chip->info->max_vid,
-	};
+	struct mv88e6xxx_vtu_entry vlan;
 	u16 fid;
 	int err;
 
@@ -1805,6 +1805,9 @@ static int mv88e6xxx_port_db_dump(struct mv88e6xxx_chip *chip, int port,
 		return err;
 
 	/* Dump VLANs' Filtering Information Databases */
+	vlan.vid = chip->info->max_vid;
+	vlan.valid = false;
+
 	do {
 		err = mv88e6xxx_vtu_getnext(chip, &vlan);
 		if (err)
-- 
2.22.0

[PATCH net-next 3/5] net: dsa: mv88e6xxx: call vtu_getnext directly in db load/purge

[Vivien Didelot]

mv88e6xxx_vtu_getnext is simple enough to call it directly in the
mv88e6xxx_port_db_load_purge function and explicit the return code
expected by switchdev for software VLANs when an hardware VLAN does
not exist.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c825fa3477fa..42ab57dbc790 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1540,23 +1540,36 @@ static int mv88e6xxx_port_db_load_purge(struct mv88e6xxx_chip *chip, int port,
 					const unsigned char *addr, u16 vid,
 					u8 state)
 {
-	struct mv88e6xxx_vtu_entry vlan;
 	struct mv88e6xxx_atu_entry entry;
+	struct mv88e6xxx_vtu_entry vlan;
+	u16 fid;
 	int err;
 
 	/* Null VLAN ID corresponds to the port private database */
-	if (vid == 0)
-		err = mv88e6xxx_port_get_fid(chip, port, &vlan.fid);
-	else
-		err = mv88e6xxx_vtu_get(chip, vid, &vlan, false);
-	if (err)
-		return err;
+	if (vid == 0) {
+		err = mv88e6xxx_port_get_fid(chip, port, &fid);
+		if (err)
+			return err;
+	} else {
+		vlan.vid = vid - 1;
+		vlan.valid = false;
+
+		err = mv88e6xxx_vtu_getnext(chip, &vlan);
+		if (err)
+			return err;
+
+		/* switchdev expects -EOPNOTSUPP to honor software VLANs */
+		if (vlan.vid != vid || !vlan.valid)
+			return -EOPNOTSUPP;
+
+		fid = vlan.fid;
+	}
 
 	entry.state = MV88E6XXX_G1_ATU_DATA_STATE_UNUSED;
 	ether_addr_copy(entry.mac, addr);
 	eth_addr_dec(entry.mac);
 
-	err = mv88e6xxx_g1_atu_getnext(chip, vlan.fid, &entry);
+	err = mv88e6xxx_g1_atu_getnext(chip, fid, &entry);
 	if (err)
 		return err;
 
@@ -1577,7 +1590,7 @@ static int mv88e6xxx_port_db_load_purge(struct mv88e6xxx_chip *chip, int port,
 		entry.state = state;
 	}
 
-	return mv88e6xxx_g1_atu_loadpurge(chip, vlan.fid, &entry);
+	return mv88e6xxx_g1_atu_loadpurge(chip, fid, &entry);
 }
 
 static int mv88e6xxx_port_add_broadcast(struct mv88e6xxx_chip *chip, int port,
-- 
2.22.0

[PATCH net-next 4/5] net: dsa: mv88e6xxx: call vtu_getnext directly in vlan_del

[Vivien Didelot]

Wrapping mv88e6xxx_vtu_getnext makes the code less easy to read.
Explicit the call to mv88e6xxx_vtu_getnext in _mv88e6xxx_port_vlan_del
and the return value expected by switchdev in case of software VLANs.

At the same time, rename the helper using an old underscore convention.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 42ab57dbc790..50a6dbcc669c 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1671,18 +1671,27 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
 	mv88e6xxx_reg_unlock(chip);
 }
 
-static int _mv88e6xxx_port_vlan_del(struct mv88e6xxx_chip *chip,
-				    int port, u16 vid)
+static int mv88e6xxx_port_vlan_leave(struct mv88e6xxx_chip *chip,
+				     int port, u16 vid)
 {
 	struct mv88e6xxx_vtu_entry vlan;
 	int i, err;
 
-	err = mv88e6xxx_vtu_get(chip, vid, &vlan, false);
+	if (!vid)
+		return -EOPNOTSUPP;
+
+	vlan.vid = vid - 1;
+	vlan.valid = false;
+
+	err = mv88e6xxx_vtu_getnext(chip, &vlan);
 	if (err)
 		return err;
 
-	/* Tell switchdev if this VLAN is handled in software */
-	if (vlan.member[port] == MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER)
+	/* If the VLAN doesn't exist in hardware or the port isn't a member,
+	 * tell switchdev that this VLAN is likely handled in software.
+	 */
+	if (vlan.vid != vid || !vlan.valid ||
+	    vlan.member[port] == MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER)
 		return -EOPNOTSUPP;
 
 	vlan.member[port] = MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER;
@@ -1721,7 +1730,7 @@ static int mv88e6xxx_port_vlan_del(struct dsa_switch *ds, int port,
 		goto unlock;
 
 	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
-		err = _mv88e6xxx_port_vlan_del(chip, port, vid);
+		err = mv88e6xxx_port_vlan_leave(chip, port, vid);
 		if (err)
 			goto unlock;
 
-- 
2.22.0

[PATCH net-next 5/5] net: dsa: mv88e6xxx: call vtu_getnext directly in vlan_add

[Vivien Didelot]

Wrapping mv88e6xxx_vtu_getnext makes the code less easy to read and
_mv88e6xxx_port_vlan_add is the only function requiring the preparation
of a new VLAN entry.

To simplify things up, remove the mv88e6xxx_vtu_get wrapper and
explicit the VLAN lookup in _mv88e6xxx_port_vlan_add. This rework
also avoids programming the broadcast entries again when changing a
port's membership, e.g. from tagged to untagged.

At the same time, rename the helper using an old underscore convention.

Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 93 +++++++++++++++-----------------
 1 file changed, 44 insertions(+), 49 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 50a6dbcc669c..8c4216e7a4bb 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1401,43 +1401,6 @@ static int mv88e6xxx_atu_new(struct mv88e6xxx_chip *chip, u16 *fid)
 	return mv88e6xxx_g1_atu_flush(chip, *fid, true);
 }
 
-static int mv88e6xxx_vtu_get(struct mv88e6xxx_chip *chip, u16 vid,
-			     struct mv88e6xxx_vtu_entry *entry, bool new)
-{
-	int err;
-
-	if (!vid)
-		return -EOPNOTSUPP;
-
-	entry->vid = vid - 1;
-	entry->valid = false;
-
-	err = mv88e6xxx_vtu_getnext(chip, entry);
-	if (err)
-		return err;
-
-	if (entry->vid == vid && entry->valid)
-		return 0;
-
-	if (new) {
-		int i;
-
-		/* Initialize a fresh VLAN entry */
-		memset(entry, 0, sizeof(*entry));
-		entry->vid = vid;
-
-		/* Exclude all ports */
-		for (i = 0; i < mv88e6xxx_num_ports(chip); ++i)
-			entry->member[i] =
-				MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER;
-
-		return mv88e6xxx_atu_new(chip, &entry->fid);
-	}
-
-	/* switchdev expects -EOPNOTSUPP to honor software VLANs */
-	return -EOPNOTSUPP;
-}
-
 static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
 					u16 vid_begin, u16 vid_end)
 {
@@ -1616,26 +1579,58 @@ static int mv88e6xxx_broadcast_setup(struct mv88e6xxx_chip *chip, u16 vid)
 	return 0;
 }
 
-static int _mv88e6xxx_port_vlan_add(struct mv88e6xxx_chip *chip, int port,
+static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
 				    u16 vid, u8 member)
 {
+	const u8 non_member = MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER;
 	struct mv88e6xxx_vtu_entry vlan;
-	int err;
+	int i, err;
 
-	err = mv88e6xxx_vtu_get(chip, vid, &vlan, true);
+	if (!vid)
+		return -EOPNOTSUPP;
+
+	vlan.vid = vid - 1;
+	vlan.valid = false;
+
+	err = mv88e6xxx_vtu_getnext(chip, &vlan);
 	if (err)
 		return err;
 
-	if (vlan.valid && vlan.member[port] == member)
-		return 0;
-	vlan.valid = true;
-	vlan.member[port] = member;
+	if (vlan.vid != vid || !vlan.valid) {
+		memset(&vlan, 0, sizeof(vlan));
 
-	err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
-	if (err)
-		return err;
+		err = mv88e6xxx_atu_new(chip, &vlan.fid);
+		if (err)
+			return err;
 
-	return mv88e6xxx_broadcast_setup(chip, vid);
+		for (i = 0; i < mv88e6xxx_num_ports(chip); ++i)
+			if (i == port)
+				vlan.member[i] = member;
+			else
+				vlan.member[i] = non_member;
+
+		vlan.vid = vid;
+		vlan.valid = true;
+
+		err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
+		if (err)
+			return err;
+
+		err = mv88e6xxx_broadcast_setup(chip, vlan.vid);
+		if (err)
+			return err;
+	} else if (vlan.member[port] != member) {
+		vlan.member[port] = member;
+
+		err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
+		if (err)
+			return err;
+	} else {
+		dev_info(chip->dev, "p%d: already a member of VLAN %d\n",
+			 port, vid);
+	}
+
+	return 0;
 }
 
 static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
@@ -1660,7 +1655,7 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
 	mv88e6xxx_reg_lock(chip);
 
 	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid)
-		if (_mv88e6xxx_port_vlan_add(chip, port, vid, member))
+		if (mv88e6xxx_port_vlan_join(chip, port, vid, member))
 			dev_err(ds->dev, "p%d: failed to add VLAN %d%c\n", port,
 				vid, untagged ? 'u' : 't');
 
-- 
2.22.0

Re: [PATCH net-next 0/5] net: dsa: mv88e6xxx: avoid some redundant VTU operations

[David Miller]

From: Vivien Didelot <vivien.didelot@gmail.com>
Date: Thu,  1 Aug 2019 14:36:32 -0400

> The mv88e6xxx driver currently uses a mv88e6xxx_vtu_get wrapper to get a
> single entry and uses a boolean to eventually initialize a fresh one.
> 
> However the fresh entry is only needed in one place and mv88e6xxx_vtu_getnext
> is simple enough to call it directly. Doing so makes the code easier to read,
> especially for the return code expected by switchdev to honor software VLANs.
> 
> In addition to not loading the VTU again when an entry is already correctly
> programmed, this also allows to avoid programming the broadcast entries
> again when updating a port's membership, from e.g. tagged to untagged.
> 
> This patch series removes the mv88e6xxx_vtu_get wrapper in favor of direct
> calls to mv88e6xxx_vtu_getnext, and also renames the _mv88e6xxx_port_vlan_add
> and _mv88e6xxx_port_vlan_del helpers using an old underscore prefix convention.
> 
> In case the port's membership is already correctly programmed in hardware,
> the following debug message may be printed:
> 
>     [  745.989884] mv88e6085 2188000.ethernet-1:00: p4: already a member of VLAN 42

Series applied, thanks Vivien.