net: introduce helper dev_change_tx_queue_len()

This patch promotes the local change_tx_queue_len() to a core
helper function, dev_change_tx_queue_len(), so that rtnetlink
and net-sysfs could share the code. This also prepares for the
following patch.

Note, the -EFAULT in the original code doesn't make sense,
we should propagate the errno from notifiers.

Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index cd46d3d..4c77f39 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3331,6 +3331,7 @@ int dev_get_alias(const struct net_device *, char *, size_t);
 int dev_change_net_namespace(struct net_device *, struct net *, const char *);
 int __dev_set_mtu(struct net_device *, int);
 int dev_set_mtu(struct net_device *, int);
+int dev_change_tx_queue_len(struct net_device *, unsigned long);
 void dev_set_group(struct net_device *, int);
 int dev_set_mac_address(struct net_device *, struct sockaddr *);
 int dev_change_carrier(struct net_device *, bool new_carrier);

diff --git a/net/core/dev.c b/net/core/dev.c
index 858501b..520c246 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7048,6 +7048,34 @@ int dev_set_mtu(struct net_device *dev, int new_mtu)
 EXPORT_SYMBOL(dev_set_mtu);
 
 /**
+ *     dev_change_tx_queue_len - Change TX queue length of a netdevice
+ *     @dev: device
+ *     @new_len: new tx queue length
+ */
+int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len)
+{
+       unsigned int orig_len = dev->tx_queue_len;
+       int res;
+
+       if (new_len != (unsigned int)new_len)
+               return -ERANGE;
+
+       if (new_len != orig_len) {
+               dev->tx_queue_len = new_len;
+               res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev);
+               res = notifier_to_errno(res);
+               if (res) {
+                       netdev_err(dev,
+                                  "refused to change device tx_queue_len\n");
+                       dev->tx_queue_len = orig_len;
+                       return res;
+               }
+       }
+
+       return 0;
+}
+
+/**
  *     dev_set_group - Change group this device belongs to
  *     @dev: device
  *     @new_group: group this device should belong to

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index c4a28f4..60a5ad2 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -346,29 +346,6 @@ static ssize_t flags_store(struct device *dev, struct device_attribute *attr,
 }
 NETDEVICE_SHOW_RW(flags, fmt_hex);
 
-static int change_tx_queue_len(struct net_device *dev, unsigned long new_len)
-{
-       unsigned int orig_len = dev->tx_queue_len;
-       int res;
-
-       if (new_len != (unsigned int)new_len)
-               return -ERANGE;
-
-       if (new_len != orig_len) {
-               dev->tx_queue_len = new_len;
-               res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev);
-               res = notifier_to_errno(res);
-               if (res) {
-                       netdev_err(dev,
-                                  "refused to change device tx_queue_len\n");
-                       dev->tx_queue_len = orig_len;
-                       return -EFAULT;
-               }
-       }
-
-       return 0;
-}
-
 static ssize_t tx_queue_len_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
@@ -376,7 +353,7 @@ static ssize_t tx_queue_len_store(struct device *dev,
        if (!capable(CAP_NET_ADMIN))
                return -EPERM;
 
-       return netdev_store(dev, attr, buf, len, change_tx_queue_len);
+       return netdev_store(dev, attr, buf, len, dev_change_tx_queue_len);
 }
 NETDEVICE_SHOW_RW(tx_queue_len, fmt_dec);
 

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e04af7b..061e27c 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2337,19 +2337,11 @@ static int do_setlink(const struct sk_buff *skb,
 
        if (tb[IFLA_TXQLEN]) {
                unsigned int value = nla_get_u32(tb[IFLA_TXQLEN]);
-               unsigned int orig_len = dev->tx_queue_len;
-
-               if (dev->tx_queue_len ^ value) {
-                       dev->tx_queue_len = value;
-                       err = call_netdevice_notifiers(
-                             NETDEV_CHANGE_TX_QUEUE_LEN, dev);
-                       err = notifier_to_errno(err);
-                       if (err) {
-                               dev->tx_queue_len = orig_len;
-                               goto errout;
-                       }
-                       status |= DO_SETLINK_MODIFIED;
-               }
+
+               err = dev_change_tx_queue_len(dev, value);
+               if (err)
+                       goto errout;
+               status |= DO_SETLINK_MODIFIED;
        }
 
        if (tb[IFLA_GSO_MAX_SIZE]) {