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authorPavel Emelyanov <xemul@openvz.org>2008-04-15 03:35:23 -0400
committerDavid S. Miller <davem@davemloft.net>2008-04-15 03:35:23 -0400
commitc93cf61fd1d5378134f9b06703f7078067542e00 (patch)
tree5ea9e584aa2c10b9c395730ee5bb944902d3e760 /net
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>
Diffstat (limited to 'net')
-rw-r--r--net/core/net_namespace.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 7b660834a4c2..2197d51aef3b 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -5,6 +5,7 @@
5#include <linux/list.h> 5#include <linux/list.h>
6#include <linux/delay.h> 6#include <linux/delay.h>
7#include <linux/sched.h> 7#include <linux/sched.h>
8#include <linux/idr.h>
8#include <net/net_namespace.h> 9#include <net/net_namespace.h>
9 10
10/* 11/*
@@ -253,6 +254,8 @@ static void unregister_pernet_operations(struct pernet_operations *ops)
253} 254}
254#endif 255#endif
255 256
257static DEFINE_IDA(net_generic_ids);
258
256/** 259/**
257 * register_pernet_subsys - register a network namespace subsystem 260 * register_pernet_subsys - register a network namespace subsystem
258 * @ops: pernet operations structure for the subsystem 261 * @ops: pernet operations structure for the subsystem
@@ -330,6 +333,30 @@ int register_pernet_device(struct pernet_operations *ops)
330} 333}
331EXPORT_SYMBOL_GPL(register_pernet_device); 334EXPORT_SYMBOL_GPL(register_pernet_device);
332 335
336int register_pernet_gen_device(int *id, struct pernet_operations *ops)
337{
338 int error;
339 mutex_lock(&net_mutex);
340again:
341 error = ida_get_new_above(&net_generic_ids, 1, id);
342 if (error) {
343 if (error == -EAGAIN) {
344 ida_pre_get(&net_generic_ids, GFP_KERNEL);
345 goto again;
346 }
347 goto out;
348 }
349 error = register_pernet_operations(&pernet_list, ops);
350 if (error)
351 ida_remove(&net_generic_ids, *id);
352 else if (first_device == &pernet_list)
353 first_device = &ops->list;
354out:
355 mutex_unlock(&net_mutex);
356 return error;
357}
358EXPORT_SYMBOL_GPL(register_pernet_gen_device);
359
333/** 360/**
334 * unregister_pernet_device - unregister a network namespace netdevice 361 * unregister_pernet_device - unregister a network namespace netdevice
335 * @ops: pernet operations structure to manipulate 362 * @ops: pernet operations structure to manipulate
@@ -348,3 +375,14 @@ void unregister_pernet_device(struct pernet_operations *ops)
348 mutex_unlock(&net_mutex); 375 mutex_unlock(&net_mutex);
349} 376}
350EXPORT_SYMBOL_GPL(unregister_pernet_device); 377EXPORT_SYMBOL_GPL(unregister_pernet_device);
378
379void unregister_pernet_gen_device(int id, struct pernet_operations *ops)
380{
381 mutex_lock(&net_mutex);
382 if (&ops->list == first_device)
383 first_device = first_device->next;
384 unregister_pernet_operations(ops);
385 ida_remove(&net_generic_ids, id);
386 mutex_unlock(&net_mutex);
387}
388EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);