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authorPavel Emelyanov <xemul@openvz.org>2008-04-15 00:35:23 -0700
committerDavid S. Miller <davem@davemloft.net>2008-04-15 00:35:23 -0700
commitc93cf61fd1d5378134f9b06703f7078067542e00 (patch)
tree5ea9e584aa2c10b9c395730ee5bb944902d3e760
parent31efdf0530b6351b0658d35a602a0f2d6bc2ed6f (diff)
[NETNS]: The net-subsys IDs generator.
To make some per-net generic pointers, we need some way to address them, i.e. - IDs. This is simple IDA-based IDs generator for pernet subsystems. Addressing questions about potential checkpoint/restart problems: these IDs are "lite-offsets" within the net structure and are by no means supposed to be exported to the userspace. Since it will be used in the nearest future by devices only (tun, vlan, tunnels, bridge, etc), I make it resemble the functionality of register_pernet_device(). The new ids is stored in the *id pointer _before_ calling the init callback to make this id available in this callback. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/net_namespace.h2
-rw-r--r--net/core/net_namespace.c38
2 files changed, 40 insertions, 0 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index e2aee2689ab..72fad1a0956 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -185,6 +185,8 @@ extern int register_pernet_subsys(struct pernet_operations *);
extern void unregister_pernet_subsys(struct pernet_operations *);
extern int register_pernet_device(struct pernet_operations *);
extern void unregister_pernet_device(struct pernet_operations *);
+extern int register_pernet_gen_device(int *id, struct pernet_operations *);
+extern void unregister_pernet_gen_device(int id, struct pernet_operations *);
struct ctl_path;
struct ctl_table;
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 7b660834a4c..2197d51aef3 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -5,6 +5,7 @@
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/sched.h>
+#include <linux/idr.h>
#include <net/net_namespace.h>
/*
@@ -253,6 +254,8 @@ static void unregister_pernet_operations(struct pernet_operations *ops)
}
#endif
+static DEFINE_IDA(net_generic_ids);
+
/**
* register_pernet_subsys - register a network namespace subsystem
* @ops: pernet operations structure for the subsystem
@@ -330,6 +333,30 @@ int register_pernet_device(struct pernet_operations *ops)
}
EXPORT_SYMBOL_GPL(register_pernet_device);
+int register_pernet_gen_device(int *id, struct pernet_operations *ops)
+{
+ int error;
+ mutex_lock(&net_mutex);
+again:
+ error = ida_get_new_above(&net_generic_ids, 1, id);
+ if (error) {
+ if (error == -EAGAIN) {
+ ida_pre_get(&net_generic_ids, GFP_KERNEL);
+ goto again;
+ }
+ goto out;
+ }
+ error = register_pernet_operations(&pernet_list, ops);
+ if (error)
+ ida_remove(&net_generic_ids, *id);
+ else if (first_device == &pernet_list)
+ first_device = &ops->list;
+out:
+ mutex_unlock(&net_mutex);
+ return error;
+}
+EXPORT_SYMBOL_GPL(register_pernet_gen_device);
+
/**
* unregister_pernet_device - unregister a network namespace netdevice
* @ops: pernet operations structure to manipulate
@@ -348,3 +375,14 @@ void unregister_pernet_device(struct pernet_operations *ops)
mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_device);
+
+void unregister_pernet_gen_device(int id, struct pernet_operations *ops)
+{
+ mutex_lock(&net_mutex);
+ if (&ops->list == first_device)
+ first_device = first_device->next;
+ unregister_pernet_operations(ops);
+ ida_remove(&net_generic_ids, id);
+ mutex_unlock(&net_mutex);
+}
+EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);