net: core: decouple ifalias get/set from rtnl lock (6c557001) · Commits · 戴 / test

include/linux/netdevice.h

+7 −1

Original line number	Diff line number	Diff line
		@@ -826,6 +826,11 @@ struct xfrmdev_ops {
		};
		#endif

		struct dev_ifalias {
		struct rcu_head rcuhead;
		char ifalias[];
		};

		/*
		* This structure defines the management hooks for network devices.
		* The following hooks can be defined; unless noted otherwise, they are
		@@ -1632,7 +1637,7 @@ enum netdev_priv_flags {
		struct net_device {
		char name[IFNAMSIZ];
		struct hlist_node name_hlist;
		char *ifalias;
		struct dev_ifalias __rcu *ifalias;
		/*
		* I/O specific fields
		* FIXME: Merge these and struct ifmap into one
		@@ -3275,6 +3280,7 @@ void __dev_notify_flags(struct net_device *, unsigned int old_flags,
		unsigned int gchanges);
		int dev_change_name(struct net_device , const char );
		int dev_set_alias(struct net_device , const char , size_t);
		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);

net/core/dev.c

+39 −13

Original line number	Diff line number	Diff line
		@@ -188,6 +188,8 @@ static struct napi_struct *napi_by_id(unsigned int napi_id);
		DEFINE_RWLOCK(dev_base_lock);
		EXPORT_SYMBOL(dev_base_lock);

		static DEFINE_MUTEX(ifalias_mutex);

		/* protects napi_hash addition/deletion and napi_gen_id */
		static DEFINE_SPINLOCK(napi_hash_lock);

		@@ -1265,29 +1267,53 @@ rollback:
		*/
		int dev_set_alias(struct net_device dev, const char alias, size_t len)
		{
		char *new_ifalias;

		ASSERT_RTNL();
		struct dev_ifalias *new_alias = NULL;

		if (len >= IFALIASZ)
		return -EINVAL;

		if (!len) {
		kfree(dev->ifalias);
		dev->ifalias = NULL;
		return 0;
		if (len) {
		new_alias = kmalloc(sizeof(*new_alias) + len + 1, GFP_KERNEL);
		if (!new_alias)
		return -ENOMEM;

		memcpy(new_alias->ifalias, alias, len);
		new_alias->ifalias[len] = 0;
		}

		new_ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
		if (!new_ifalias)
		return -ENOMEM;
		dev->ifalias = new_ifalias;
		memcpy(dev->ifalias, alias, len);
		dev->ifalias[len] = 0;
		mutex_lock(&ifalias_mutex);
		rcu_swap_protected(dev->ifalias, new_alias,
		mutex_is_locked(&ifalias_mutex));
		mutex_unlock(&ifalias_mutex);

		if (new_alias)
		kfree_rcu(new_alias, rcuhead);

		return len;
		}

		/**
		* dev_get_alias - get ifalias of a device
		* @dev: device
		* @alias: buffer to store name of ifalias
		* @len: size of buffer
		*
		* get ifalias for a device. Caller must make sure dev cannot go
		* away, e.g. rcu read lock or own a reference count to device.
		*/
		int dev_get_alias(const struct net_device dev, char name, size_t len)
		{
		const struct dev_ifalias *alias;
		int ret = 0;

		rcu_read_lock();
		alias = rcu_dereference(dev->ifalias);
		if (alias)
		ret = snprintf(name, len, "%s", alias->ifalias);
		rcu_read_unlock();

		return ret;
		}

		/**
		* netdev_features_change - device changes features

net/core/net-sysfs.c

+8 −9

Original line number	Diff line number	Diff line
		@@ -391,10 +391,7 @@ static ssize_t ifalias_store(struct device dev, struct device_attribute attr,
		if (len > 0 && buf[len - 1] == '\n')
		--count;

		if (!rtnl_trylock())
		return restart_syscall();
		ret = dev_set_alias(netdev, buf, count);
		rtnl_unlock();

		return ret < 0 ? ret : len;
		}
		@@ -403,13 +400,12 @@ static ssize_t ifalias_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		const struct net_device *netdev = to_net_dev(dev);
		char tmp[IFALIASZ];
		ssize_t ret = 0;

		if (!rtnl_trylock())
		return restart_syscall();
		if (netdev->ifalias)
		ret = sprintf(buf, "%s\n", netdev->ifalias);
		rtnl_unlock();
		ret = dev_get_alias(netdev, tmp, sizeof(tmp));
		if (ret > 0)
		ret = sprintf(buf, "%s\n", tmp);
		return ret;
		}
		static DEVICE_ATTR_RW(ifalias);
		@@ -1488,7 +1484,10 @@ static void netdev_release(struct device *d)

		BUG_ON(dev->reg_state != NETREG_RELEASED);

		kfree(dev->ifalias);
		/* no need to wait for rcu grace period:
		* device is dead and about to be freed.
		*/
		kfree(rcu_access_pointer(dev->ifalias));
		netdev_freemem(dev);
		}

net/core/rtnetlink.c

+11 −2

Original line number	Diff line number	Diff line
		@@ -1366,6 +1366,16 @@ static int nla_put_iflink(struct sk_buff skb, const struct net_device dev)
		return nla_put_u32(skb, IFLA_LINK, ifindex);
		}

		static noinline_for_stack int nla_put_ifalias(struct sk_buff *skb,
		struct net_device *dev)
		{
		char buf[IFALIASZ];
		int ret;

		ret = dev_get_alias(dev, buf, sizeof(buf));
		return ret > 0 ? nla_put_string(skb, IFLA_IFALIAS, buf) : 0;
		}

		static int rtnl_fill_link_netnsid(struct sk_buff *skb,
		const struct net_device *dev)
		{
		@@ -1425,8 +1435,7 @@ static int rtnl_fill_ifinfo(struct sk_buff skb, struct net_device dev,
		nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) \|\|
		(dev->qdisc &&
		nla_put_string(skb, IFLA_QDISC, dev->qdisc->ops->id)) \|\|
		(dev->ifalias &&
		nla_put_string(skb, IFLA_IFALIAS, dev->ifalias)) \|\|
		nla_put_ifalias(skb, dev) \|\|
		nla_put_u32(skb, IFLA_CARRIER_CHANGES,
		atomic_read(&dev->carrier_changes)) \|\|
		nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down))

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