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04672fe6 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
15530dfd IPG |
2 | /* |
3 | * Linux WiMAX | |
4 | * Mappping of generic netlink family IDs to net devices | |
5 | * | |
15530dfd IPG |
6 | * Copyright (C) 2005-2006 Intel Corporation <linux-wimax@intel.com> |
7 | * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> | |
8 | * | |
15530dfd IPG |
9 | * We assign a single generic netlink family ID to each device (to |
10 | * simplify lookup). | |
11 | * | |
12 | * We need a way to map family ID to a wimax_dev pointer. | |
13 | * | |
14 | * The idea is to use a very simple lookup. Using a netlink attribute | |
15 | * with (for example) the interface name implies a heavier search over | |
16 | * all the network devices; seemed kind of a waste given that we know | |
17 | * we are looking for a WiMAX device and that most systems will have | |
18 | * just a single WiMAX adapter. | |
19 | * | |
20 | * We put all the WiMAX devices in the system in a linked list and | |
21 | * match the generic link family ID against the list. | |
22 | * | |
23 | * By using a linked list, the case of a single adapter in the system | |
24 | * becomes (almost) no overhead, while still working for many more. If | |
25 | * it ever goes beyond two, I'll be surprised. | |
26 | */ | |
27 | #include <linux/device.h> | |
28 | #include <net/genetlink.h> | |
29 | #include <linux/netdevice.h> | |
30 | #include <linux/list.h> | |
31 | #include <linux/wimax.h> | |
32 | #include "wimax-internal.h" | |
33 | ||
34 | ||
35 | #define D_SUBMODULE id_table | |
36 | #include "debug-levels.h" | |
37 | ||
38 | ||
39 | static DEFINE_SPINLOCK(wimax_id_table_lock); | |
40 | static struct list_head wimax_id_table = LIST_HEAD_INIT(wimax_id_table); | |
41 | ||
42 | ||
43 | /* | |
44 | * wimax_id_table_add - add a gennetlink familiy ID / wimax_dev mapping | |
45 | * | |
46 | * @wimax_dev: WiMAX device descriptor to associate to the Generic | |
47 | * Netlink family ID. | |
48 | * | |
49 | * Look for an empty spot in the ID table; if none found, double the | |
50 | * table's size and get the first spot. | |
51 | */ | |
52 | void wimax_id_table_add(struct wimax_dev *wimax_dev) | |
53 | { | |
54 | d_fnstart(3, NULL, "(wimax_dev %p)\n", wimax_dev); | |
55 | spin_lock(&wimax_id_table_lock); | |
56 | list_add(&wimax_dev->id_table_node, &wimax_id_table); | |
57 | spin_unlock(&wimax_id_table_lock); | |
58 | d_fnend(3, NULL, "(wimax_dev %p)\n", wimax_dev); | |
59 | } | |
60 | ||
61 | ||
62 | /* | |
63 | * wimax_get_netdev_by_info - lookup a wimax_dev from the gennetlink info | |
64 | * | |
65 | * The generic netlink family ID has been filled out in the | |
66 | * nlmsghdr->nlmsg_type field, so we pull it from there, look it up in | |
67 | * the mapping table and reference the wimax_dev. | |
68 | * | |
69 | * When done, the reference should be dropped with | |
70 | * 'dev_put(wimax_dev->net_dev)'. | |
71 | */ | |
72 | struct wimax_dev *wimax_dev_get_by_genl_info( | |
73 | struct genl_info *info, int ifindex) | |
74 | { | |
75 | struct wimax_dev *wimax_dev = NULL; | |
76 | ||
77 | d_fnstart(3, NULL, "(info %p ifindex %d)\n", info, ifindex); | |
78 | spin_lock(&wimax_id_table_lock); | |
79 | list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { | |
80 | if (wimax_dev->net_dev->ifindex == ifindex) { | |
81 | dev_hold(wimax_dev->net_dev); | |
1d7b33f7 | 82 | goto found; |
15530dfd IPG |
83 | } |
84 | } | |
1d7b33f7 IPG |
85 | wimax_dev = NULL; |
86 | d_printf(1, NULL, "wimax: no devices found with ifindex %d\n", | |
87 | ifindex); | |
88 | found: | |
15530dfd IPG |
89 | spin_unlock(&wimax_id_table_lock); |
90 | d_fnend(3, NULL, "(info %p ifindex %d) = %p\n", | |
91 | info, ifindex, wimax_dev); | |
92 | return wimax_dev; | |
93 | } | |
94 | ||
95 | ||
96 | /* | |
97 | * wimax_id_table_rm - Remove a gennetlink familiy ID / wimax_dev mapping | |
98 | * | |
99 | * @id: family ID to remove from the table | |
100 | */ | |
101 | void wimax_id_table_rm(struct wimax_dev *wimax_dev) | |
102 | { | |
103 | spin_lock(&wimax_id_table_lock); | |
104 | list_del_init(&wimax_dev->id_table_node); | |
105 | spin_unlock(&wimax_id_table_lock); | |
106 | } | |
107 | ||
108 | ||
109 | /* | |
110 | * Release the gennetlink family id / mapping table | |
111 | * | |
d48e470f IPG |
112 | * On debug, verify that the table is empty upon removal. We want the |
113 | * code always compiled, to ensure it doesn't bit rot. It will be | |
114 | * compiled out if CONFIG_BUG is disabled. | |
15530dfd IPG |
115 | */ |
116 | void wimax_id_table_release(void) | |
117 | { | |
d48e470f IPG |
118 | struct wimax_dev *wimax_dev; |
119 | ||
15530dfd IPG |
120 | #ifndef CONFIG_BUG |
121 | return; | |
122 | #endif | |
15530dfd IPG |
123 | spin_lock(&wimax_id_table_lock); |
124 | list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { | |
28b7deae | 125 | pr_err("BUG: %s wimax_dev %p ifindex %d not cleared\n", |
15530dfd IPG |
126 | __func__, wimax_dev, wimax_dev->net_dev->ifindex); |
127 | WARN_ON(1); | |
128 | } | |
129 | spin_unlock(&wimax_id_table_lock); | |
130 | } |