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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/ccid.c
3 *
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * CCID infrastructure
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include "ccid.h"
15
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -080016static struct ccid_operations *ccids[CCID_MAX];
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070017#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
18static atomic_t ccids_lockct = ATOMIC_INIT(0);
19static DEFINE_SPINLOCK(ccids_lock);
20
21/*
22 * The strategy is: modifications ccids vector are short, do not sleep and
23 * veeery rare, but read access should be free of any exclusive locks.
24 */
25static void ccids_write_lock(void)
26{
27 spin_lock(&ccids_lock);
28 while (atomic_read(&ccids_lockct) != 0) {
29 spin_unlock(&ccids_lock);
30 yield();
31 spin_lock(&ccids_lock);
32 }
33}
34
35static inline void ccids_write_unlock(void)
36{
37 spin_unlock(&ccids_lock);
38}
39
40static inline void ccids_read_lock(void)
41{
42 atomic_inc(&ccids_lockct);
Oleg Nesterovd725fdc2007-08-10 15:21:17 -070043 smp_mb__after_atomic_inc();
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070044 spin_unlock_wait(&ccids_lock);
45}
46
47static inline void ccids_read_unlock(void)
48{
49 atomic_dec(&ccids_lockct);
50}
51
52#else
53#define ccids_write_lock() do { } while(0)
54#define ccids_write_unlock() do { } while(0)
55#define ccids_read_lock() do { } while(0)
56#define ccids_read_unlock() do { } while(0)
57#endif
58
Christoph Lametere18b8902006-12-06 20:33:20 -080059static struct kmem_cache *ccid_kmem_cache_create(int obj_size, const char *fmt,...)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070060{
Christoph Lametere18b8902006-12-06 20:33:20 -080061 struct kmem_cache *slab;
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -080062 char slab_name_fmt[32], *slab_name;
63 va_list args;
64
65 va_start(args, fmt);
66 vsnprintf(slab_name_fmt, sizeof(slab_name_fmt), fmt, args);
67 va_end(args);
68
69 slab_name = kstrdup(slab_name_fmt, GFP_KERNEL);
70 if (slab_name == NULL)
71 return NULL;
72 slab = kmem_cache_create(slab_name, sizeof(struct ccid) + obj_size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +090073 SLAB_HWCACHE_ALIGN, NULL);
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -080074 if (slab == NULL)
75 kfree(slab_name);
76 return slab;
77}
78
Christoph Lametere18b8902006-12-06 20:33:20 -080079static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -080080{
81 if (slab != NULL) {
82 const char *name = kmem_cache_name(slab);
83
84 kmem_cache_destroy(slab);
85 kfree(name);
86 }
87}
88
89int ccid_register(struct ccid_operations *ccid_ops)
90{
91 int err = -ENOBUFS;
92
93 ccid_ops->ccid_hc_rx_slab =
94 ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
95 "%s_hc_rx_sock",
96 ccid_ops->ccid_name);
97 if (ccid_ops->ccid_hc_rx_slab == NULL)
98 goto out;
99
100 ccid_ops->ccid_hc_tx_slab =
101 ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
102 "%s_hc_tx_sock",
103 ccid_ops->ccid_name);
104 if (ccid_ops->ccid_hc_tx_slab == NULL)
105 goto out_free_rx_slab;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700106
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700107 ccids_write_lock();
108 err = -EEXIST;
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800109 if (ccids[ccid_ops->ccid_id] == NULL) {
110 ccids[ccid_ops->ccid_id] = ccid_ops;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700111 err = 0;
112 }
113 ccids_write_unlock();
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800114 if (err != 0)
115 goto out_free_tx_slab;
116
117 pr_info("CCID: Registered CCID %d (%s)\n",
118 ccid_ops->ccid_id, ccid_ops->ccid_name);
119out:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700120 return err;
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800121out_free_tx_slab:
122 ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
123 ccid_ops->ccid_hc_tx_slab = NULL;
124 goto out;
125out_free_rx_slab:
126 ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
127 ccid_ops->ccid_hc_rx_slab = NULL;
128 goto out;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700129}
130
131EXPORT_SYMBOL_GPL(ccid_register);
132
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800133int ccid_unregister(struct ccid_operations *ccid_ops)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700134{
135 ccids_write_lock();
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800136 ccids[ccid_ops->ccid_id] = NULL;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700137 ccids_write_unlock();
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800138
139 ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
140 ccid_ops->ccid_hc_tx_slab = NULL;
141 ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
142 ccid_ops->ccid_hc_rx_slab = NULL;
143
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700144 pr_info("CCID: Unregistered CCID %d (%s)\n",
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800145 ccid_ops->ccid_id, ccid_ops->ccid_name);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700146 return 0;
147}
148
149EXPORT_SYMBOL_GPL(ccid_unregister);
150
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800151struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700152{
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800153 struct ccid_operations *ccid_ops;
154 struct ccid *ccid = NULL;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700155
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700156 ccids_read_lock();
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800157#ifdef CONFIG_KMOD
158 if (ccids[id] == NULL) {
159 /* We only try to load if in process context */
160 ccids_read_unlock();
161 if (gfp & GFP_ATOMIC)
162 goto out;
163 request_module("net-dccp-ccid-%d", id);
164 ccids_read_lock();
165 }
166#endif
167 ccid_ops = ccids[id];
168 if (ccid_ops == NULL)
169 goto out_unlock;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700170
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800171 if (!try_module_get(ccid_ops->ccid_owner))
172 goto out_unlock;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700173
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700174 ccids_read_unlock();
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800175
176 ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
177 ccid_ops->ccid_hc_tx_slab, gfp);
178 if (ccid == NULL)
179 goto out_module_put;
180 ccid->ccid_ops = ccid_ops;
181 if (rx) {
182 memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
183 if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
184 ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
185 goto out_free_ccid;
186 } else {
187 memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
188 if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
189 ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
190 goto out_free_ccid;
191 }
192out:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700193 return ccid;
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800194out_unlock:
195 ccids_read_unlock();
196 goto out;
197out_free_ccid:
198 kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
199 ccid_ops->ccid_hc_tx_slab, ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700200 ccid = NULL;
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800201out_module_put:
202 module_put(ccid_ops->ccid_owner);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700203 goto out;
204}
205
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800206EXPORT_SYMBOL_GPL(ccid_new);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700207
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800208struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, gfp_t gfp)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700209{
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800210 return ccid_new(id, sk, 1, gfp);
211}
212
213EXPORT_SYMBOL_GPL(ccid_hc_rx_new);
214
215struct ccid *ccid_hc_tx_new(unsigned char id,struct sock *sk, gfp_t gfp)
216{
217 return ccid_new(id, sk, 0, gfp);
218}
219
220EXPORT_SYMBOL_GPL(ccid_hc_tx_new);
221
222static void ccid_delete(struct ccid *ccid, struct sock *sk, int rx)
223{
224 struct ccid_operations *ccid_ops;
225
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700226 if (ccid == NULL)
227 return;
228
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800229 ccid_ops = ccid->ccid_ops;
230 if (rx) {
231 if (ccid_ops->ccid_hc_rx_exit != NULL)
232 ccid_ops->ccid_hc_rx_exit(sk);
233 kmem_cache_free(ccid_ops->ccid_hc_rx_slab, ccid);
234 } else {
235 if (ccid_ops->ccid_hc_tx_exit != NULL)
236 ccid_ops->ccid_hc_tx_exit(sk);
237 kmem_cache_free(ccid_ops->ccid_hc_tx_slab, ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700238 }
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800239 ccids_read_lock();
240 if (ccids[ccid_ops->ccid_id] != NULL)
241 module_put(ccid_ops->ccid_owner);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700242 ccids_read_unlock();
243}
244
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800245void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
246{
247 ccid_delete(ccid, sk, 1);
248}
249
250EXPORT_SYMBOL_GPL(ccid_hc_rx_delete);
251
252void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
253{
254 ccid_delete(ccid, sk, 0);
255}
256
257EXPORT_SYMBOL_GPL(ccid_hc_tx_delete);