Merge branch 'txq_max_rate'

Or Gerlitz says:

====================
Add max rate TXQ attribute

Add the ability to set a max-rate limitation for TX queues.
The attribute name is maxrate and the units are Mbs, to make
it similar to the existing max-rate limitation knobs (ETS and
SRIOV ndo calls).

changes from V2:
  - added Documentation (thanks Florian and Tom)
  - rebased to latest net-next to comply with the swdev ndo removal
  - addressed more feedback from Dave on the comments style

changes from V1:
  - addressed feedback from Dave

changes from V0:
  - addressed feedback from Sergei

John Fastabend (1):
  net: Add max rate tx queue attribute
====================

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

1 files changed, 55 insertions, 12 deletions

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index cf30620a88e1..7e58bd7ec232 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -951,6 +951,60 @@ static ssize_t show_trans_timeout(struct netdev_queue *queue,
         return sprintf(buf, "%lu", trans_timeout);
 }
 
+#ifdef CONFIG_XPS
+static inline unsigned int get_netdev_queue_index(struct netdev_queue *queue)
+{
+        struct net_device *dev = queue->dev;
+        int i;
+
+        for (i = 0; i < dev->num_tx_queues; i++)
+                if (queue == &dev->_tx[i])
+                        break;
+
+        BUG_ON(i >= dev->num_tx_queues);
+
+        return i;
+}
+
+static ssize_t show_tx_maxrate(struct netdev_queue *queue,
+                               struct netdev_queue_attribute *attribute,
+                               char *buf)
+{
+        return sprintf(buf, "%lu\n", queue->tx_maxrate);
+}
+
+static ssize_t set_tx_maxrate(struct netdev_queue *queue,
+                              struct netdev_queue_attribute *attribute,
+                              const char *buf, size_t len)
+{
+        struct net_device *dev = queue->dev;
+        int err, index = get_netdev_queue_index(queue);
+        u32 rate = 0;
+
+        err = kstrtou32(buf, 10, &rate);
+        if (err < 0)
+                return err;
+
+        if (!rtnl_trylock())
+                return restart_syscall();
+
+        err = -EOPNOTSUPP;
+        if (dev->netdev_ops->ndo_set_tx_maxrate)
+                err = dev->netdev_ops->ndo_set_tx_maxrate(dev, index, rate);
+
+        rtnl_unlock();
+        if (!err) {
+                queue->tx_maxrate = rate;
+                return len;
+        }
+        return err;
+}
+
+static struct netdev_queue_attribute queue_tx_maxrate =
+        __ATTR(tx_maxrate, S_IRUGO | S_IWUSR,
+               show_tx_maxrate, set_tx_maxrate);
+#endif
+
 static struct netdev_queue_attribute queue_trans_timeout =
         __ATTR(tx_timeout, S_IRUGO, show_trans_timeout, NULL);
 
@@ -1065,18 +1119,6 @@ static struct attribute_group dql_group = {
 #endif /* CONFIG_BQL */
 
 #ifdef CONFIG_XPS
-static unsigned int get_netdev_queue_index(struct netdev_queue *queue)
-{
-        struct net_device *dev = queue->dev;
-        unsigned int i;
-
-        i = queue - dev->_tx;
-        BUG_ON(i >= dev->num_tx_queues);
-
-        return i;
-}
-
-
 static ssize_t show_xps_map(struct netdev_queue *queue,
                             struct netdev_queue_attribute *attribute, char *buf)
 {
@@ -1153,6 +1195,7 @@ static struct attribute *netdev_queue_default_attrs[] = {
         &queue_trans_timeout.attr,
 #ifdef CONFIG_XPS
         &xps_cpus_attribute.attr,
+        &queue_tx_maxrate.attr,
 #endif
         NULL
 };