bonding: Use a per netns implementation of /sys/class/net/bonding_masters.

This fixes a network namespace misfeature that bonding_masters looked at
current instead of the remembering the context where in which
/sys/class/net/bonding_masters was opened in to see which network
namespace to act upon.

This removes the need for sysfs to handle tagged directories with
untagged members allowing for a conceptually simpler sysfs
implementation.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 38 insertions, 21 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 6191e633728..41430baa132 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4888,6 +4888,7 @@ static int __net_init bond_net_init(struct net *net)
         INIT_LIST_HEAD(&bn->dev_list);
 
         bond_create_proc_dir(bn);
+        bond_create_sysfs(bn);
         
         return 0;
 }
@@ -4896,6 +4897,7 @@ static void __net_exit bond_net_exit(struct net *net)
 {
         struct bond_net *bn = net_generic(net, bond_net_id);
 
+        bond_destroy_sysfs(bn);
         bond_destroy_proc_dir(bn);
 }
 
@@ -4933,10 +4935,6 @@ static int __init bonding_init(void)
                         goto err;
         }
 
-        res = bond_create_sysfs();
-        if (res)
-                goto err;
-
         register_netdevice_notifier(&bond_netdev_notifier);
         register_inetaddr_notifier(&bond_inetaddr_notifier);
 out:
@@ -4954,7 +4952,6 @@ static void __exit bonding_exit(void)
         unregister_netdevice_notifier(&bond_netdev_notifier);
         unregister_inetaddr_notifier(&bond_inetaddr_notifier);
 
-        bond_destroy_sysfs();
         bond_destroy_debugfs();
 
         rtnl_link_unregister(&bond_link_ops);
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 2dfb4bf9008..6044ff809c2 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -55,8 +55,8 @@ static ssize_t bonding_show_bonds(struct class *cls,
                                   struct class_attribute *attr,
                                   char *buf)
 {
-        struct net *net = current->nsproxy->net_ns;
-        struct bond_net *bn = net_generic(net, bond_net_id);
+        struct bond_net *bn =
+                container_of(attr, struct bond_net, class_attr_bonding_masters);
         int res = 0;
         struct bonding *bond;
 
@@ -79,9 +79,8 @@ static ssize_t bonding_show_bonds(struct class *cls,
         return res;
 }
 
-static struct net_device *bond_get_by_name(struct net *net, const char *ifname)
+static struct net_device *bond_get_by_name(struct bond_net *bn, const char *ifname)
 {
-        struct bond_net *bn = net_generic(net, bond_net_id);
         struct bonding *bond;
 
         list_for_each_entry(bond, &bn->dev_list, bond_list) {
@@ -103,7 +102,8 @@ static ssize_t bonding_store_bonds(struct class *cls,
                                    struct class_attribute *attr,
                                    const char *buffer, size_t count)
 {
-        struct net *net = current->nsproxy->net_ns;
+        struct bond_net *bn =
+                container_of(attr, struct bond_net, class_attr_bonding_masters);
         char command[IFNAMSIZ + 1] = {0, };
         char *ifname;
         int rv, res = count;
@@ -116,7 +116,7 @@ static ssize_t bonding_store_bonds(struct class *cls,
 
         if (command[0] == '+') {
                 pr_info("%s is being created...\n", ifname);
-                rv = bond_create(net, ifname);
+                rv = bond_create(bn->net, ifname);
                 if (rv) {
                         if (rv == -EEXIST)
                                 pr_info("%s already exists.\n", ifname);
@@ -128,7 +128,7 @@ static ssize_t bonding_store_bonds(struct class *cls,
                 struct net_device *bond_dev;
 
                 rtnl_lock();
-                bond_dev = bond_get_by_name(net, ifname);
+                bond_dev = bond_get_by_name(bn, ifname);
                 if (bond_dev) {
                         pr_info("%s is being deleted...\n", ifname);
                         unregister_netdevice(bond_dev);
@@ -150,9 +150,24 @@ err_no_cmd:
         return -EPERM;
 }
 
+static const void *bonding_namespace(struct class *cls,
+                                     const struct class_attribute *attr)
+{
+        const struct bond_net *bn =
+                container_of(attr, struct bond_net, class_attr_bonding_masters);
+        return bn->net;
+}
+
 /* class attribute for bond_masters file.  This ends up in /sys/class/net */
-static CLASS_ATTR(bonding_masters,  S_IWUSR | S_IRUGO,
-                  bonding_show_bonds, bonding_store_bonds);
+static const struct class_attribute class_attr_bonding_masters = {
+        .attr = {
+                .name = "bonding_masters",
+                .mode = S_IWUSR | S_IRUGO,
+        },
+        .show = bonding_show_bonds,
+        .store = bonding_store_bonds,
+        .namespace = bonding_namespace,
+};
 
 int bond_create_slave_symlinks(struct net_device *master,
                                struct net_device *slave)
@@ -1655,11 +1670,13 @@ static struct attribute_group bonding_group = {
  * Initialize sysfs.  This sets up the bonding_masters file in
  * /sys/class/net.
  */
-int bond_create_sysfs(void)
+int bond_create_sysfs(struct bond_net *bn)
 {
         int ret;
 
-        ret = netdev_class_create_file(&class_attr_bonding_masters);
+        bn->class_attr_bonding_masters = class_attr_bonding_masters;
+
+        ret = netdev_class_create_file(&bn->class_attr_bonding_masters);
         /*
          * Permit multiple loads of the module by ignoring failures to
          * create the bonding_masters sysfs file.  Bonding devices
@@ -1673,7 +1690,7 @@ int bond_create_sysfs(void)
          */
         if (ret == -EEXIST) {
                 /* Is someone being kinky and naming a device bonding_master? */
-                if (__dev_get_by_name(&init_net,
+                if (__dev_get_by_name(bn->net,
                                       class_attr_bonding_masters.attr.name))
                         pr_err("network device named %s already exists in sysfs",
                                class_attr_bonding_masters.attr.name);
@@ -1687,9 +1704,9 @@ int bond_create_sysfs(void)
 /*
  * Remove /sys/class/net/bonding_masters.
  */
-void bond_destroy_sysfs(void)
+void bond_destroy_sysfs(struct bond_net *bn)
 {
-        netdev_class_remove_file(&class_attr_bonding_masters);
+        netdev_class_remove_file(&bn->class_attr_bonding_masters);
 }
 
 /*
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index e8233661560..82fec5fc75d 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -379,11 +379,13 @@ static inline bool bond_is_slave_inactive(struct slave *slave)
         return slave->inactive;
 }
 
+struct bond_net;
+
 struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr);
 int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev);
 int bond_create(struct net *net, const char *name);
-int bond_create_sysfs(void);
-void bond_destroy_sysfs(void);
+int bond_create_sysfs(struct bond_net *net);
+void bond_destroy_sysfs(struct bond_net *net);
 void bond_prepare_sysfs_group(struct bonding *bond);
 int bond_create_slave_symlinks(struct net_device *master, struct net_device *slave);
 void bond_destroy_slave_symlinks(struct net_device *master, struct net_device *slave);
@@ -409,6 +411,7 @@ struct bond_net {
 #ifdef CONFIG_PROC_FS
         struct proc_dir_entry * proc_dir;
 #endif
+        struct class_attribute  class_attr_bonding_masters;
 };
 
 #ifdef CONFIG_PROC_FS