1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
/*
* net/dccp/ccid.c
*
* An implementation of the DCCP protocol
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* CCID infrastructure
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include "ccid.h"
static struct ccid_operations *ccids[CCID_MAX];
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
static atomic_t ccids_lockct = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(ccids_lock);
/*
* The strategy is: modifications ccids vector are short, do not sleep and
* veeery rare, but read access should be free of any exclusive locks.
*/
static void ccids_write_lock(void)
{
spin_lock(&ccids_lock);
while (atomic_read(&ccids_lockct) != 0) {
spin_unlock(&ccids_lock);
yield();
spin_lock(&ccids_lock);
}
}
static inline void ccids_write_unlock(void)
{
spin_unlock(&ccids_lock);
}
static inline void ccids_read_lock(void)
{
atomic_inc(&ccids_lockct);
spin_unlock_wait(&ccids_lock);
}
static inline void ccids_read_unlock(void)
{
atomic_dec(&ccids_lockct);
}
#else
#define ccids_write_lock() do { } while(0)
#define ccids_write_unlock() do { } while(0)
#define ccids_read_lock() do { } while(0)
#define ccids_read_unlock() do { } while(0)
#endif
static kmem_cache_t *ccid_kmem_cache_create(int obj_size, const char *fmt,...)
{
kmem_cache_t *slab;
char slab_name_fmt[32], *slab_name;
va_list args;
va_start(args, fmt);
vsnprintf(slab_name_fmt, sizeof(slab_name_fmt), fmt, args);
va_end(args);
slab_name = kstrdup(slab_name_fmt, GFP_KERNEL);
if (slab_name == NULL)
return NULL;
slab = kmem_cache_create(slab_name, sizeof(struct ccid) + obj_size, 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (slab == NULL)
kfree(slab_name);
return slab;
}
static void ccid_kmem_cache_destroy(kmem_cache_t *slab)
{
if (slab != NULL) {
const char *name = kmem_cache_name(slab);
kmem_cache_destroy(slab);
kfree(name);
}
}
int ccid_register(struct ccid_operations *ccid_ops)
{
int err = -ENOBUFS;
ccid_ops->ccid_hc_rx_slab =
ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
"%s_hc_rx_sock",
ccid_ops->ccid_name);
if (ccid_ops->ccid_hc_rx_slab == NULL)
goto out;
ccid_ops->ccid_hc_tx_slab =
ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
"%s_hc_tx_sock",
ccid_ops->ccid_name);
if (ccid_ops->ccid_hc_tx_slab == NULL)
goto out_free_rx_slab;
ccids_write_lock();
err = -EEXIST;
if (ccids[ccid_ops->ccid_id] == NULL) {
ccids[ccid_ops->ccid_id] = ccid_ops;
err = 0;
}
ccids_write_unlock();
if (err != 0)
goto out_free_tx_slab;
pr_info("CCID: Registered CCID %d (%s)\n",
ccid_ops->ccid_id, ccid_ops->ccid_name);
out:
return err;
out_free_tx_slab:
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
ccid_ops->ccid_hc_tx_slab = NULL;
goto out;
out_free_rx_slab:
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
ccid_ops->ccid_hc_rx_slab = NULL;
goto out;
}
EXPORT_SYMBOL_GPL(ccid_register);
int ccid_unregister(struct ccid_operations *ccid_ops)
{
ccids_write_lock();
ccids[ccid_ops->ccid_id] = NULL;
ccids_write_unlock();
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
ccid_ops->ccid_hc_tx_slab = NULL;
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
ccid_ops->ccid_hc_rx_slab = NULL;
pr_info("CCID: Unregistered CCID %d (%s)\n",
ccid_ops->ccid_id, ccid_ops->ccid_name);
return 0;
}
EXPORT_SYMBOL_GPL(ccid_unregister);
struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp)
{
struct ccid_operations *ccid_ops;
struct ccid *ccid = NULL;
ccids_read_lock();
#ifdef CONFIG_KMOD
if (ccids[id] == NULL) {
/* We only try to load if in process context */
ccids_read_unlock();
if (gfp & GFP_ATOMIC)
goto out;
request_module("net-dccp-ccid-%d", id);
ccids_read_lock();
}
#endif
ccid_ops = ccids[id];
if (ccid_ops == NULL)
goto out_unlock;
if (!try_module_get(ccid_ops->ccid_owner))
goto out_unlock;
ccids_read_unlock();
ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
ccid_ops->ccid_hc_tx_slab, gfp);
if (ccid == NULL)
goto out_module_put;
ccid->ccid_ops = ccid_ops;
if (rx) {
memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
goto out_free_ccid;
} else {
memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
goto out_free_ccid;
}
out:
return ccid;
out_unlock:
ccids_read_unlock();
goto out;
out_free_ccid:
kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
ccid_ops->ccid_hc_tx_slab, ccid);
ccid = NULL;
out_module_put:
module_put(ccid_ops->ccid_owner);
goto out;
}
EXPORT_SYMBOL_GPL(ccid_new);
struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, gfp_t gfp)
{
return ccid_new(id, sk, 1, gfp);
}
EXPORT_SYMBOL_GPL(ccid_hc_rx_new);
struct ccid *ccid_hc_tx_new(unsigned char id,struct sock *sk, gfp_t gfp)
{
return ccid_new(id, sk, 0, gfp);
}
EXPORT_SYMBOL_GPL(ccid_hc_tx_new);
static void ccid_delete(struct ccid *ccid, struct sock *sk, int rx)
{
struct ccid_operations *ccid_ops;
if (ccid == NULL)
return;
ccid_ops = ccid->ccid_ops;
if (rx) {
if (ccid_ops->ccid_hc_rx_exit != NULL)
ccid_ops->ccid_hc_rx_exit(sk);
kmem_cache_free(ccid_ops->ccid_hc_rx_slab, ccid);
} else {
if (ccid_ops->ccid_hc_tx_exit != NULL)
ccid_ops->ccid_hc_tx_exit(sk);
kmem_cache_free(ccid_ops->ccid_hc_tx_slab, ccid);
}
ccids_read_lock();
if (ccids[ccid_ops->ccid_id] != NULL)
module_put(ccid_ops->ccid_owner);
ccids_read_unlock();
}
void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
{
ccid_delete(ccid, sk, 1);
}
EXPORT_SYMBOL_GPL(ccid_hc_rx_delete);
void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
{
ccid_delete(ccid, sk, 0);
}
EXPORT_SYMBOL_GPL(ccid_hc_tx_delete);
|
