net: dsa: make dp->bridge_num one-based

I have seen too many bugs already due to the fact that we must encode an
invalid dp->bridge_num as a negative value, because the natural tendency
is to check that invalid value using (!dp->bridge_num). Latest example
can be seen in commit 1bec0f05062c ("net: dsa: fix bridge_num not
getting cleared after ports leaving the bridge").

Convert the existing users to assume that dp->bridge_num == 0 is the
encoding for invalid, and valid bridge numbers start from 1.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index f00cbf5..de3401b 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1250,10 +1250,10 @@ static u16 mv88e6xxx_port_vlan(struct mv88e6xxx_chip *chip, int dev, int port)
        /* dev is a virtual bridge */
        } else {
                list_for_each_entry(dp, &dst->ports, list) {
-                       if (dp->bridge_num < 0)
+                       if (!dp->bridge_num)
                                continue;
 
-                       if (dp->bridge_num + 1 + dst->last_switch != dev)
+                       if (dp->bridge_num + dst->last_switch != dev)
                                continue;
 
                        br = dp->bridge_dev;
@@ -2527,9 +2527,9 @@ static void mv88e6xxx_crosschip_bridge_leave(struct dsa_switch *ds,
  * physical switches, so start from beyond that range.
  */
 static int mv88e6xxx_map_virtual_bridge_to_pvt(struct dsa_switch *ds,
-                                              int bridge_num)
+                                              unsigned int bridge_num)
 {
-       u8 dev = bridge_num + ds->dst->last_switch + 1;
+       u8 dev = bridge_num + ds->dst->last_switch;
        struct mv88e6xxx_chip *chip = ds->priv;
        int err;
 
@@ -2542,14 +2542,14 @@ static int mv88e6xxx_map_virtual_bridge_to_pvt(struct dsa_switch *ds,
 
 static int mv88e6xxx_bridge_tx_fwd_offload(struct dsa_switch *ds, int port,
                                           struct net_device *br,
-                                          int bridge_num)
+                                          unsigned int bridge_num)
 {
        return mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge_num);
 }
 
 static void mv88e6xxx_bridge_tx_fwd_unoffload(struct dsa_switch *ds, int port,
                                              struct net_device *br,
-                                             int bridge_num)
+                                             unsigned int bridge_num)
 {
        int err;
 

diff --git a/include/linux/dsa/8021q.h b/include/linux/dsa/8021q.h
index 254b165..0af4371 100644 (file)
--- a/include/linux/dsa/8021q.h
+++ b/include/linux/dsa/8021q.h
@@ -38,13 +38,13 @@ void dsa_8021q_rcv(struct sk_buff *skb, int *source_port, int *switch_id);
 
 int dsa_tag_8021q_bridge_tx_fwd_offload(struct dsa_switch *ds, int port,
                                        struct net_device *br,
-                                       int bridge_num);
+                                       unsigned int bridge_num);
 
 void dsa_tag_8021q_bridge_tx_fwd_unoffload(struct dsa_switch *ds, int port,
                                           struct net_device *br,
-                                          int bridge_num);
+                                          unsigned int bridge_num);
 
-u16 dsa_8021q_bridge_tx_fwd_offload_vid(int bridge_num);
+u16 dsa_8021q_bridge_tx_fwd_offload_vid(unsigned int bridge_num);
 
 u16 dsa_tag_8021q_tx_vid(const struct dsa_port *dp);
 

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 8ca9d50..a23cfba 100644 (file)
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -257,7 +257,7 @@ struct dsa_port {
        bool                    learning;
        u8                      stp_state;
        struct net_device       *bridge_dev;
-       int                     bridge_num;
+       unsigned int            bridge_num;
        struct devlink_port     devlink_port;
        bool                    devlink_port_setup;
        struct phylink          *pl;
@@ -754,11 +754,11 @@ struct dsa_switch_ops {
        /* Called right after .port_bridge_join() */
        int     (*port_bridge_tx_fwd_offload)(struct dsa_switch *ds, int port,
                                              struct net_device *bridge,
-                                             int bridge_num);
+                                             unsigned int bridge_num);
        /* Called right before .port_bridge_leave() */
        void    (*port_bridge_tx_fwd_unoffload)(struct dsa_switch *ds, int port,
                                                struct net_device *bridge,
-                                               int bridge_num);
+                                               unsigned int bridge_num);
        void    (*port_stp_state_set)(struct dsa_switch *ds, int port,
                                      u8 state);
        void    (*port_fast_age)(struct dsa_switch *ds, int port);

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 826957b..9606e56 100644 (file)
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -141,23 +141,23 @@ static int dsa_bridge_num_find(const struct net_device *bridge_dev)
         */
        list_for_each_entry(dst, &dsa_tree_list, list)
                list_for_each_entry(dp, &dst->ports, list)
-                       if (dp->bridge_dev == bridge_dev &&
-                           dp->bridge_num != -1)
+                       if (dp->bridge_dev == bridge_dev && dp->bridge_num)
                                return dp->bridge_num;
 
-       return -1;
+       return 0;
 }
 
-int dsa_bridge_num_get(const struct net_device *bridge_dev, int max)
+unsigned int dsa_bridge_num_get(const struct net_device *bridge_dev, int max)
 {
-       int bridge_num = dsa_bridge_num_find(bridge_dev);
+       unsigned int bridge_num = dsa_bridge_num_find(bridge_dev);
 
-       if (bridge_num < 0) {
+       if (!bridge_num) {
                /* First port that offloads TX forwarding for this bridge */
-               bridge_num = find_first_zero_bit(&dsa_fwd_offloading_bridges,
-                                                DSA_MAX_NUM_OFFLOADING_BRIDGES);
+               bridge_num = find_next_zero_bit(&dsa_fwd_offloading_bridges,
+                                               DSA_MAX_NUM_OFFLOADING_BRIDGES,
+                                               1);
                if (bridge_num >= max)
-                       return -1;
+                       return 0;
 
                set_bit(bridge_num, &dsa_fwd_offloading_bridges);
        }
@@ -165,12 +165,13 @@ int dsa_bridge_num_get(const struct net_device *bridge_dev, int max)
        return bridge_num;
 }
 
-void dsa_bridge_num_put(const struct net_device *bridge_dev, int bridge_num)
+void dsa_bridge_num_put(const struct net_device *bridge_dev,
+                       unsigned 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) < 0)
+       if (!dsa_bridge_num_find(bridge_dev))
                clear_bit(bridge_num, &dsa_fwd_offloading_bridges);
 }
 
@@ -1184,7 +1185,6 @@ static struct dsa_port *dsa_port_touch(struct dsa_switch *ds, int index)
 
        dp->ds = ds;
        dp->index = index;
-       dp->bridge_num = -1;
 
        INIT_LIST_HEAD(&dp->list);
        list_add_tail(&dp->list, &dst->ports);

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 3fb2c37..70c4a5b 100644 (file)
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -546,8 +546,9 @@ int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
                              struct net_device *master,
                              const struct dsa_device_ops *tag_ops,
                              const struct dsa_device_ops *old_tag_ops);
-int dsa_bridge_num_get(const struct net_device *bridge_dev, int max);
-void dsa_bridge_num_put(const struct net_device *bridge_dev, int bridge_num);
+unsigned int dsa_bridge_num_get(const struct net_device *bridge_dev, int max);
+void dsa_bridge_num_put(const struct net_device *bridge_dev,
+                       unsigned int bridge_num);
 
 /* tag_8021q.c */
 int dsa_tag_8021q_bridge_join(struct dsa_switch *ds,

diff --git a/net/dsa/port.c b/net/dsa/port.c
index 6d5ebe6..9a77bd1 100644 (file)
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -273,14 +273,14 @@ static void dsa_port_switchdev_unsync_attrs(struct dsa_port *dp)
 static void dsa_port_bridge_tx_fwd_unoffload(struct dsa_port *dp,
                                             struct net_device *bridge_dev)
 {
-       int bridge_num = dp->bridge_num;
+       unsigned int bridge_num = dp->bridge_num;
        struct dsa_switch *ds = dp->ds;
 
        /* No bridge TX forwarding offload => do nothing */
-       if (!ds->ops->port_bridge_tx_fwd_unoffload || dp->bridge_num == -1)
+       if (!ds->ops->port_bridge_tx_fwd_unoffload || !dp->bridge_num)
                return;
 
-       dp->bridge_num = -1;
+       dp->bridge_num = 0;
 
        dsa_bridge_num_put(bridge_dev, bridge_num);
 
@@ -295,14 +295,15 @@ static bool dsa_port_bridge_tx_fwd_offload(struct dsa_port *dp,
                                           struct net_device *bridge_dev)
 {
        struct dsa_switch *ds = dp->ds;
-       int bridge_num, err;
+       unsigned int bridge_num;
+       int err;
 
        if (!ds->ops->port_bridge_tx_fwd_offload)
                return false;
 
        bridge_num = dsa_bridge_num_get(bridge_dev,
                                        ds->num_fwd_offloading_bridges);
-       if (bridge_num < 0)
+       if (!bridge_num)
                return false;
 
        dp->bridge_num = bridge_num;

diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index 72cac2c..df59f16 100644 (file)
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -67,10 +67,12 @@
 #define DSA_8021Q_PORT(x)              (((x) << DSA_8021Q_PORT_SHIFT) & \
                                                 DSA_8021Q_PORT_MASK)
 
-u16 dsa_8021q_bridge_tx_fwd_offload_vid(int bridge_num)
+u16 dsa_8021q_bridge_tx_fwd_offload_vid(unsigned int bridge_num)
 {
-       /* The VBID value of 0 is reserved for precise TX */
-       return DSA_8021Q_DIR_TX | DSA_8021Q_VBID(bridge_num + 1);
+       /* The VBID value of 0 is reserved for precise TX, but it is also
+        * reserved/invalid for the bridge_num, so all is well.
+        */
+       return DSA_8021Q_DIR_TX | DSA_8021Q_VBID(bridge_num);
 }
 EXPORT_SYMBOL_GPL(dsa_8021q_bridge_tx_fwd_offload_vid);
 
@@ -409,7 +411,7 @@ int dsa_tag_8021q_bridge_leave(struct dsa_switch *ds,
 
 int dsa_tag_8021q_bridge_tx_fwd_offload(struct dsa_switch *ds, int port,
                                        struct net_device *br,
-                                       int bridge_num)
+                                       unsigned int bridge_num)
 {
        u16 tx_vid = dsa_8021q_bridge_tx_fwd_offload_vid(bridge_num);
 
@@ -420,7 +422,7 @@ EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_tx_fwd_offload);
 
 void dsa_tag_8021q_bridge_tx_fwd_unoffload(struct dsa_switch *ds, int port,
                                           struct net_device *br,
-                                          int bridge_num)
+                                          unsigned int bridge_num)
 {
        u16 tx_vid = dsa_8021q_bridge_tx_fwd_offload_vid(bridge_num);
 

diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index b3da4b2..a7d70ae 100644 (file)
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -140,7 +140,7 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
                 * packets on behalf of a virtual switch device with an index
                 * past the physical switches.
                 */
-               tag_dev = dst->last_switch + 1 + dp->bridge_num;
+               tag_dev = dst->last_switch + dp->bridge_num;
                tag_port = 0;
        } else {
                cmd = DSA_CMD_FROM_CPU;