net: dsa: move dsa_port :: stp_state near dsa_port :: mac

The MAC address of a port is 6 octets in size, and this creates a 2
octet hole after it. There are some other u8 members of struct dsa_port
that we can put in that hole. One such member is the stp_state.

Before:

pahole -C dsa_port net/dsa/slave.o
struct dsa_port {
        union {
                struct net_device * master;              /*     0     8 */
                struct net_device * slave;               /*     0     8 */
        };                                               /*     0     8 */
        const struct dsa_device_ops  * tag_ops;          /*     8     8 */
        struct dsa_switch_tree *   dst;                  /*    16     8 */
        struct sk_buff *           (*rcv)(struct sk_buff *, struct net_device *); /*    24     8 */
        enum {
                DSA_PORT_TYPE_UNUSED = 0,
                DSA_PORT_TYPE_CPU    = 1,
                DSA_PORT_TYPE_DSA    = 2,
                DSA_PORT_TYPE_USER   = 3,
        } type;                                          /*    32     4 */

        /* XXX 4 bytes hole, try to pack */

        struct dsa_switch *        ds;                   /*    40     8 */
        unsigned int               index;                /*    48     4 */

        /* XXX 4 bytes hole, try to pack */

        const char  *              name;                 /*    56     8 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        struct dsa_port *          cpu_dp;               /*    64     8 */
        u8                         mac[6];               /*    72     6 */

        /* XXX 2 bytes hole, try to pack */

        struct device_node *       dn;                   /*    80     8 */
        unsigned int               ageing_time;          /*    88     4 */
        bool                       vlan_filtering;       /*    92     1 */
        bool                       learning;             /*    93     1 */
        u8                         stp_state;            /*    94     1 */

        /* XXX 1 byte hole, try to pack */

        struct dsa_bridge *        bridge;               /*    96     8 */
        struct devlink_port        devlink_port;         /*   104   288 */
        /* --- cacheline 6 boundary (384 bytes) was 8 bytes ago --- */
        bool                       devlink_port_setup;   /*   392     1 */

        /* XXX 7 bytes hole, try to pack */

        struct phylink *           pl;                   /*   400     8 */
        struct phylink_config      pl_config;            /*   408    40 */
        /* --- cacheline 7 boundary (448 bytes) --- */
        struct net_device *        lag_dev;              /*   448     8 */
        bool                       lag_tx_enabled;       /*   456     1 */

        /* XXX 7 bytes hole, try to pack */

        struct net_device *        hsr_dev;              /*   464     8 */
        struct list_head           list;                 /*   472    16 */
        const struct ethtool_ops  * orig_ethtool_ops;    /*   488     8 */
        const struct dsa_netdevice_ops  * netdev_ops;    /*   496     8 */
        struct mutex               addr_lists_lock;      /*   504    32 */
        /* --- cacheline 8 boundary (512 bytes) was 24 bytes ago --- */
        struct list_head           fdbs;                 /*   536    16 */
        struct list_head           mdbs;                 /*   552    16 */
        bool                       setup;                /*   568     1 */

        /* size: 576, cachelines: 9, members: 30 */
        /* sum members: 544, holes: 6, sum holes: 25 */
        /* padding: 7 */
};

After:

pahole -C dsa_port net/dsa/slave.o
struct dsa_port {
        union {
                struct net_device * master;              /*     0     8 */
                struct net_device * slave;               /*     0     8 */
        };                                               /*     0     8 */
        const struct dsa_device_ops  * tag_ops;          /*     8     8 */
        struct dsa_switch_tree *   dst;                  /*    16     8 */
        struct sk_buff *           (*rcv)(struct sk_buff *, struct net_device *); /*    24     8 */
        enum {
                DSA_PORT_TYPE_UNUSED = 0,
                DSA_PORT_TYPE_CPU    = 1,
                DSA_PORT_TYPE_DSA    = 2,
                DSA_PORT_TYPE_USER   = 3,
        } type;                                          /*    32     4 */

        /* XXX 4 bytes hole, try to pack */

        struct dsa_switch *        ds;                   /*    40     8 */
        unsigned int               index;                /*    48     4 */

        /* XXX 4 bytes hole, try to pack */

        const char  *              name;                 /*    56     8 */
        /* --- cacheline 1 boundary (64 bytes) --- */
        struct dsa_port *          cpu_dp;               /*    64     8 */
        u8                         mac[6];               /*    72     6 */
        u8                         stp_state;            /*    78     1 */

        /* XXX 1 byte hole, try to pack */

        struct device_node *       dn;                   /*    80     8 */
        unsigned int               ageing_time;          /*    88     4 */
        bool                       vlan_filtering;       /*    92     1 */
        bool                       learning;             /*    93     1 */

        /* XXX 2 bytes hole, try to pack */

        struct dsa_bridge *        bridge;               /*    96     8 */
        struct devlink_port        devlink_port;         /*   104   288 */
        /* --- cacheline 6 boundary (384 bytes) was 8 bytes ago --- */
        bool                       devlink_port_setup;   /*   392     1 */

        /* XXX 7 bytes hole, try to pack */

        struct phylink *           pl;                   /*   400     8 */
        struct phylink_config      pl_config;            /*   408    40 */
        /* --- cacheline 7 boundary (448 bytes) --- */
        struct net_device *        lag_dev;              /*   448     8 */
        bool                       lag_tx_enabled;       /*   456     1 */

        /* XXX 7 bytes hole, try to pack */

        struct net_device *        hsr_dev;              /*   464     8 */
        struct list_head           list;                 /*   472    16 */
        const struct ethtool_ops  * orig_ethtool_ops;    /*   488     8 */
        const struct dsa_netdevice_ops  * netdev_ops;    /*   496     8 */
        struct mutex               addr_lists_lock;      /*   504    32 */
        /* --- cacheline 8 boundary (512 bytes) was 24 bytes ago --- */
        struct list_head           fdbs;                 /*   536    16 */
        struct list_head           mdbs;                 /*   552    16 */
        bool                       setup;                /*   568     1 */

        /* size: 576, cachelines: 9, members: 30 */
        /* sum members: 544, holes: 6, sum holes: 25 */
        /* padding: 7 */
};
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -258,12 +258,14 @@ struct dsa_port {
 	const char		*name;
 	struct dsa_port		*cpu_dp;
 	u8			mac[ETH_ALEN];
+
+	u8			stp_state;
+
 	struct device_node	*dn;
 	unsigned int		ageing_time;
 	bool			vlan_filtering;
 	/* Managed by DSA on user ports and by drivers on CPU and DSA ports */
 	bool			learning;
-	u8			stp_state;
 	struct dsa_bridge	*bridge;
 	struct devlink_port	devlink_port;
 	bool			devlink_port_setup;