net-sysfs: add support for device-specific rx queue sysfs attributes

Extend existing support for netdevice receive queue sysfs attributes to
permit a device-specific attribute group. Initial use case for this
support will be to allow the virtio-net device to export per-receive
queue mergeable receive buffer size.

Signed-off-by: Michael Dalton <mwdalton@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 4 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d7668b881d08..e985231fe04b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -668,15 +668,28 @@ extern struct rps_sock_flow_table __rcu *rps_sock_flow_table;
 bool rps_may_expire_flow(struct net_device *dev, u16 rxq_index, u32 flow_id,
                          u16 filter_id);
 #endif
+#endif /* CONFIG_RPS */
 
 /* This structure contains an instance of an RX queue. */
 struct netdev_rx_queue {
+#ifdef CONFIG_RPS
         struct rps_map __rcu            *rps_map;
         struct rps_dev_flow_table __rcu *rps_flow_table;
+#endif
         struct kobject                  kobj;
         struct net_device               *dev;
 } ____cacheline_aligned_in_smp;
-#endif /* CONFIG_RPS */
+
+/*
+ * RX queue sysfs structures and functions.
+ */
+struct rx_queue_attribute {
+        struct attribute attr;
+        ssize_t (*show)(struct netdev_rx_queue *queue,
+            struct rx_queue_attribute *attr, char *buf);
+        ssize_t (*store)(struct netdev_rx_queue *queue,
+            struct rx_queue_attribute *attr, const char *buf, size_t len);
+};
 
 #ifdef CONFIG_XPS
 /*
@@ -1313,7 +1326,7 @@ struct net_device {
                                                    unicast) */
 
 
-#ifdef CONFIG_RPS
+#ifdef CONFIG_SYSFS
         struct netdev_rx_queue  *_rx;
 
         /* Number of RX queues allocated at register_netdev() time */
@@ -1424,6 +1437,8 @@ struct net_device {
         struct device           dev;
         /* space for optional device, statistics, and wireless sysfs groups */
         const struct attribute_group *sysfs_groups[4];
+        /* space for optional per-rx queue attributes */
+        const struct attribute_group *sysfs_rx_queue_group;
 
         /* rtnetlink link ops */
         const struct rtnl_link_ops *rtnl_link_ops;
@@ -2375,7 +2390,7 @@ static inline bool netif_is_multiqueue(const struct net_device *dev)
 
 int netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq);
 
-#ifdef CONFIG_RPS
+#ifdef CONFIG_SYSFS
 int netif_set_real_num_rx_queues(struct net_device *dev, unsigned int rxq);
 #else
 static inline int netif_set_real_num_rx_queues(struct net_device *dev,
@@ -2394,7 +2409,7 @@ static inline int netif_copy_real_num_queues(struct net_device *to_dev,
                                            from_dev->real_num_tx_queues);
         if (err)
                 return err;
-#ifdef CONFIG_RPS
+#ifdef CONFIG_SYSFS
         return netif_set_real_num_rx_queues(to_dev,
                                             from_dev->real_num_rx_queues);
 #else
@@ -2402,6 +2417,18 @@ static inline int netif_copy_real_num_queues(struct net_device *to_dev,
 #endif
 }
 
+#ifdef CONFIG_SYSFS
+static inline unsigned int get_netdev_rx_queue_index(
+                struct netdev_rx_queue *queue)
+{
+        struct net_device *dev = queue->dev;
+        int index = queue - dev->_rx;
+
+        BUG_ON(index >= dev->num_rx_queues);
+        return index;
+}
+#endif
+
 #define DEFAULT_MAX_NUM_RSS_QUEUES      (8)
 int netif_get_num_default_rss_queues(void);