[PATCH v2 net-next 0/2] net: rename device's sysfs symlinks on name change

[PATCH v2 net-next 0/2] net: rename device's sysfs symlinks on name change

[Veaceslav Falico]

First patch only adds helper functions and cleans up the code a bit, second
one already does the renaming.

v1->v2:
Don't export the function, as it's used only in dev.c.

Reported-by: Ding Tianhong <dingtianhong@huawei.com>
CC: Ding Tianhong <dingtianhong@huawei.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Cong Wang <amwang@redhat.com>
CC: netdev@vger.kernel.org
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>

---
 include/linux/netdevice.h |  1 +
 net/core/dev.c            | 80 +++++++++++++++++++++++++++++++----------------
 2 files changed, 54 insertions(+), 27 deletions(-)

[PATCH v2 net-next 1/2] net: add sysfs helpers for netdev_adjacent logic

[Veaceslav Falico]

They clean up the code a bit and can be used further.

CC: Ding Tianhong <dingtianhong@huawei.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Cong Wang <amwang@redhat.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
---
 net/core/dev.c | 57 ++++++++++++++++++++++++++++++---------------------------
 1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 87312dc..c578d4e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4595,13 +4595,36 @@ struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev)
 }
 EXPORT_SYMBOL(netdev_master_upper_dev_get_rcu);
 
+int netdev_adjacent_sysfs_add(struct net_device *dev,
+			      struct net_device *adj_dev,
+			      struct list_head *dev_list)
+{
+	char linkname[IFNAMSIZ+7];
+	sprintf(linkname, dev_list == &dev->adj_list.upper ?
+		"upper_%s" : "lower_%s", adj_dev->name);
+	return sysfs_create_link(&(dev->dev.kobj), &(adj_dev->dev.kobj),
+				 linkname);
+}
+void netdev_adjacent_sysfs_del(struct net_device *dev,
+			       char *name,
+			       struct list_head *dev_list)
+{
+	char linkname[IFNAMSIZ+7];
+	sprintf(linkname, dev_list == &dev->adj_list.upper ?
+		"upper_%s" : "lower_%s", name);
+	sysfs_remove_link(&(dev->dev.kobj), linkname);
+}
+
+#define netdev_adjacent_is_neigh_list(dev, dev_list) \
+		(dev_list == &dev->adj_list.upper || \
+		 dev_list == &dev->adj_list.lower)
+
 static int __netdev_adjacent_dev_insert(struct net_device *dev,
 					struct net_device *adj_dev,
 					struct list_head *dev_list,
 					void *private, bool master)
 {
 	struct netdev_adjacent *adj;
-	char linkname[IFNAMSIZ+7];
 	int ret;
 
 	adj = __netdev_find_adj(dev, adj_dev, dev_list);
@@ -4624,16 +4647,8 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
 	pr_debug("dev_hold for %s, because of link added from %s to %s\n",
 		 adj_dev->name, dev->name, adj_dev->name);
 
-	if (dev_list == &dev->adj_list.lower) {
-		sprintf(linkname, "lower_%s", adj_dev->name);
-		ret = sysfs_create_link(&(dev->dev.kobj),
-					&(adj_dev->dev.kobj), linkname);
-		if (ret)
-			goto free_adj;
-	} else if (dev_list == &dev->adj_list.upper) {
-		sprintf(linkname, "upper_%s", adj_dev->name);
-		ret = sysfs_create_link(&(dev->dev.kobj),
-					&(adj_dev->dev.kobj), linkname);
+	if (netdev_adjacent_is_neigh_list(dev, dev_list)) {
+		ret = netdev_adjacent_sysfs_add(dev, adj_dev, dev_list);
 		if (ret)
 			goto free_adj;
 	}
@@ -4653,14 +4668,8 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
 	return 0;
 
 remove_symlinks:
-	if (dev_list == &dev->adj_list.lower) {
-		sprintf(linkname, "lower_%s", adj_dev->name);
-		sysfs_remove_link(&(dev->dev.kobj), linkname);
-	} else if (dev_list == &dev->adj_list.upper) {
-		sprintf(linkname, "upper_%s", adj_dev->name);
-		sysfs_remove_link(&(dev->dev.kobj), linkname);
-	}
-
+	if (netdev_adjacent_is_neigh_list(dev, dev_list))
+		netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);
 free_adj:
 	kfree(adj);
 	dev_put(adj_dev);
@@ -4673,7 +4682,6 @@ static void __netdev_adjacent_dev_remove(struct net_device *dev,
 					 struct list_head *dev_list)
 {
 	struct netdev_adjacent *adj;
-	char linkname[IFNAMSIZ+7];
 
 	adj = __netdev_find_adj(dev, adj_dev, dev_list);
 
@@ -4693,13 +4701,8 @@ static void __netdev_adjacent_dev_remove(struct net_device *dev,
 	if (adj->master)
 		sysfs_remove_link(&(dev->dev.kobj), "master");
 
-	if (dev_list == &dev->adj_list.lower) {
-		sprintf(linkname, "lower_%s", adj_dev->name);
-		sysfs_remove_link(&(dev->dev.kobj), linkname);
-	} else if (dev_list == &dev->adj_list.upper) {
-		sprintf(linkname, "upper_%s", adj_dev->name);
-		sysfs_remove_link(&(dev->dev.kobj), linkname);
-	}
+	if (netdev_adjacent_is_neigh_list(dev, dev_list))
+		netdev_adjacent_sysfs_del(dev, adj_dev->name, dev_list);
 
 	list_del_rcu(&adj->list);
 	pr_debug("dev_put for %s, because link removed from %s to %s\n",
-- 
1.8.4

[PATCH v2 net-next 2/2] net: rename sysfs symlinks on device name change

[Veaceslav Falico]

Currently, we don't rename the upper/lower_ifc symlinks in
/sys/class/net/*/ , which might result stale/duplicate links/names.

Fix this by adding netdev_adjacent_rename_links(dev, oldname) which renames
all the upper/lower interface's links to dev from the upper/lower_oldname
to the new name.

We don't need a rollback because only we control these symlinks and if we
fail to rename them - sysfs will anyway complain.

Reported-by: Ding Tianhong <dingtianhong@huawei.com>
CC: Ding Tianhong <dingtianhong@huawei.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Cong Wang <amwang@redhat.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
---

Notes:
    v1->v2:
    Don't export netdev_adjacent_rename_links() - it's only used in dev.c

 include/linux/netdevice.h |  1 +
 net/core/dev.c            | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a2a70cc..61f8338 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2937,6 +2937,7 @@ int netdev_master_upper_dev_link_private(struct net_device *dev,
 					 void *private);
 void netdev_upper_dev_unlink(struct net_device *dev,
 			     struct net_device *upper_dev);
+void netdev_adjacent_rename_links(struct net_device *dev, char *oldname);
 void *netdev_lower_dev_get_private(struct net_device *dev,
 				   struct net_device *lower_dev);
 int skb_checksum_help(struct sk_buff *skb);
diff --git a/net/core/dev.c b/net/core/dev.c
index c578d4e..d4f08c8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1117,6 +1117,8 @@ rollback:
 
 	write_seqcount_end(&devnet_rename_seq);
 
+	netdev_adjacent_rename_links(dev, oldname);
+
 	write_lock_bh(&dev_base_lock);
 	hlist_del_rcu(&dev->name_hlist);
 	write_unlock_bh(&dev_base_lock);
@@ -1136,6 +1138,7 @@ rollback:
 			err = ret;
 			write_seqcount_begin(&devnet_rename_seq);
 			memcpy(dev->name, oldname, IFNAMSIZ);
+			memcpy(oldname, newname, IFNAMSIZ);
 			goto rollback;
 		} else {
 			pr_err("%s: name change rollback failed: %d\n",
@@ -4971,6 +4974,25 @@ void netdev_upper_dev_unlink(struct net_device *dev,
 }
 EXPORT_SYMBOL(netdev_upper_dev_unlink);
 
+void netdev_adjacent_rename_links(struct net_device *dev, char *oldname)
+{
+	struct netdev_adjacent *iter;
+
+	list_for_each_entry(iter, &dev->adj_list.upper, list) {
+		netdev_adjacent_sysfs_del(iter->dev, oldname,
+					  &iter->dev->adj_list.lower);
+		netdev_adjacent_sysfs_add(iter->dev, dev,
+					  &iter->dev->adj_list.lower);
+	}
+
+	list_for_each_entry(iter, &dev->adj_list.lower, list) {
+		netdev_adjacent_sysfs_del(iter->dev, oldname,
+					  &iter->dev->adj_list.upper);
+		netdev_adjacent_sysfs_add(iter->dev, dev,
+					  &iter->dev->adj_list.upper);
+	}
+}
+
 void *netdev_lower_dev_get_private(struct net_device *dev,
 				   struct net_device *lower_dev)
 {
-- 
1.8.4

Re: [PATCH v2 net-next 2/2] net: rename sysfs symlinks on device name change

[Ding Tianhong]

On 2014/1/15 4:58, Veaceslav Falico wrote:
> Currently, we don't rename the upper/lower_ifc symlinks in
> /sys/class/net/*/ , which might result stale/duplicate links/names.
> 
> Fix this by adding netdev_adjacent_rename_links(dev, oldname) which renames
> all the upper/lower interface's links to dev from the upper/lower_oldname
> to the new name.
> 
> We don't need a rollback because only we control these symlinks and if we
> fail to rename them - sysfs will anyway complain.
> 
> Reported-by: Ding Tianhong <dingtianhong@huawei.com>
> CC: Ding Tianhong <dingtianhong@huawei.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: Eric Dumazet <edumazet@google.com>
> CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> CC: Cong Wang <amwang@redhat.com>
> Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
> ---
> 
> Notes:
>     v1->v2:
>     Don't export netdev_adjacent_rename_links() - it's only used in dev.c
> 
>  include/linux/netdevice.h |  1 +
>  net/core/dev.c            | 22 ++++++++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index a2a70cc..61f8338 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -2937,6 +2937,7 @@ int netdev_master_upper_dev_link_private(struct net_device *dev,
>  					 void *private);
>  void netdev_upper_dev_unlink(struct net_device *dev,
>  			     struct net_device *upper_dev);
> +void netdev_adjacent_rename_links(struct net_device *dev, char *oldname);
>  void *netdev_lower_dev_get_private(struct net_device *dev,
>  				   struct net_device *lower_dev);
>  int skb_checksum_help(struct sk_buff *skb);
> diff --git a/net/core/dev.c b/net/core/dev.c
> index c578d4e..d4f08c8 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -1117,6 +1117,8 @@ rollback:
>  
>  	write_seqcount_end(&devnet_rename_seq);
>  
> +	netdev_adjacent_rename_links(dev, oldname);
> +
>  	write_lock_bh(&dev_base_lock);
>  	hlist_del_rcu(&dev->name_hlist);
>  	write_unlock_bh(&dev_base_lock);
> @@ -1136,6 +1138,7 @@ rollback:
>  			err = ret;
>  			write_seqcount_begin(&devnet_rename_seq);
>  			memcpy(dev->name, oldname, IFNAMSIZ);
> +			memcpy(oldname, newname, IFNAMSIZ);
>  			goto rollback;
>  		} else {
>  			pr_err("%s: name change rollback failed: %d\n",
> @@ -4971,6 +4974,25 @@ void netdev_upper_dev_unlink(struct net_device *dev,
>  }
>  EXPORT_SYMBOL(netdev_upper_dev_unlink);
>  
> +void netdev_adjacent_rename_links(struct net_device *dev, char *oldname)
> +{
> +	struct netdev_adjacent *iter;
> +
> +	list_for_each_entry(iter, &dev->adj_list.upper, list) {
> +		netdev_adjacent_sysfs_del(iter->dev, oldname,
> +					  &iter->dev->adj_list.lower);
> +		netdev_adjacent_sysfs_add(iter->dev, dev,
> +					  &iter->dev->adj_list.lower);
> +	}
> +
> +	list_for_each_entry(iter, &dev->adj_list.lower, list) {
> +		netdev_adjacent_sysfs_del(iter->dev, oldname,
> +					  &iter->dev->adj_list.upper);
> +		netdev_adjacent_sysfs_add(iter->dev, dev,
> +					  &iter->dev->adj_list.upper);
> +	}
> +}
> +

why no all_adj_list, only adj_list?

I think you have add the dev to the upper_dev's upper_dev by all_adj_list, and lower_dev, so you have to check them.

Regards
Ding

>  void *netdev_lower_dev_get_private(struct net_device *dev,
>  				   struct net_device *lower_dev)
>  {
> 

Re: [PATCH v2 net-next 2/2] net: rename sysfs symlinks on device name change

[Veaceslav Falico]

On Wed, Jan 15, 2014 at 10:50:30AM +0800, Ding Tianhong wrote:
>On 2014/1/15 4:58, Veaceslav Falico wrote:
...snip...
>> +void netdev_adjacent_rename_links(struct net_device *dev, char *oldname)
>> +{
>> +	struct netdev_adjacent *iter;
>> +
>> +	list_for_each_entry(iter, &dev->adj_list.upper, list) {
>> +		netdev_adjacent_sysfs_del(iter->dev, oldname,
>> +					  &iter->dev->adj_list.lower);
>> +		netdev_adjacent_sysfs_add(iter->dev, dev,
>> +					  &iter->dev->adj_list.lower);
>> +	}
>> +
>> +	list_for_each_entry(iter, &dev->adj_list.lower, list) {
>> +		netdev_adjacent_sysfs_del(iter->dev, oldname,
>> +					  &iter->dev->adj_list.upper);
>> +		netdev_adjacent_sysfs_add(iter->dev, dev,
>> +					  &iter->dev->adj_list.upper);
>> +	}
>> +}
>> +
>
>why no all_adj_list, only adj_list?
>
>I think you have add the dev to the upper_dev's upper_dev by all_adj_list, and lower_dev, so you have to check them.

symlinks are created only for neighbour adjacent devices, which are in
adj_list.*, and are not created for all_adj_list.* devices, which contains
a 'full view' list of all adjacent devices.

>
>Regards
>Ding
>
>>  void *netdev_lower_dev_get_private(struct net_device *dev,
>>  				   struct net_device *lower_dev)
>>  {
>>
>
>

Re: [PATCH v2 net-next 2/2] net: rename sysfs symlinks on device name change

[Ding Tianhong]

On 2014/1/15 10:59, Veaceslav Falico wrote:
> On Wed, Jan 15, 2014 at 10:50:30AM +0800, Ding Tianhong wrote:
>> On 2014/1/15 4:58, Veaceslav Falico wrote:
> ...snip...
>>> +void netdev_adjacent_rename_links(struct net_device *dev, char *oldname)
>>> +{
>>> +    struct netdev_adjacent *iter;
>>> +
>>> +    list_for_each_entry(iter, &dev->adj_list.upper, list) {
>>> +        netdev_adjacent_sysfs_del(iter->dev, oldname,
>>> +                      &iter->dev->adj_list.lower);
>>> +        netdev_adjacent_sysfs_add(iter->dev, dev,
>>> +                      &iter->dev->adj_list.lower);
>>> +    }
>>> +
>>> +    list_for_each_entry(iter, &dev->adj_list.lower, list) {
>>> +        netdev_adjacent_sysfs_del(iter->dev, oldname,
>>> +                      &iter->dev->adj_list.upper);
>>> +        netdev_adjacent_sysfs_add(iter->dev, dev,
>>> +                      &iter->dev->adj_list.upper);
>>> +    }
>>> +}
>>> +
>>
>> why no all_adj_list, only adj_list?
>>
>> I think you have add the dev to the upper_dev's upper_dev by all_adj_list, and lower_dev, so you have to check them.
> 
> symlinks are created only for neighbour adjacent devices, which are in
> adj_list.*, and are not created for all_adj_list.* devices, which contains
> a 'full view' list of all adjacent devices.
> 

Yes, it return when found adj, I miss it.

>>
>> Regards
>> Ding
>>
>>>  void *netdev_lower_dev_get_private(struct net_device *dev,
>>>                     struct net_device *lower_dev)
>>>  {
>>>
>>
>>
> 
> 

Re: [PATCH v2 net-next 0/2] net: rename device's sysfs symlinks on name change

[David Miller]

From: Veaceslav Falico <vfalico@redhat.com>
Date: Tue, 14 Jan 2014 21:58:49 +0100

> First patch only adds helper functions and cleans up the code a bit, second
> one already does the renaming.
> 
> v1->v2:
> Don't export the function, as it's used only in dev.c.
> 
> Reported-by: Ding Tianhong <dingtianhong@huawei.com>
> CC: Ding Tianhong <dingtianhong@huawei.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: Eric Dumazet <edumazet@google.com>
> CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> CC: Cong Wang <amwang@redhat.com>
> CC: netdev@vger.kernel.org
> Signed-off-by: Veaceslav Falico <vfalico@redhat.com>

Series applied, thanks Vaeceslav.