4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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.
16 static struct ccid_operations
*ccids
[CCID_MAX
];
17 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
18 static atomic_t ccids_lockct
= ATOMIC_INIT(0);
19 static DEFINE_SPINLOCK(ccids_lock
);
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.
25 static void ccids_write_lock(void)
27 spin_lock(&ccids_lock
);
28 while (atomic_read(&ccids_lockct
) != 0) {
29 spin_unlock(&ccids_lock
);
31 spin_lock(&ccids_lock
);
35 static inline void ccids_write_unlock(void)
37 spin_unlock(&ccids_lock
);
40 static inline void ccids_read_lock(void)
42 atomic_inc(&ccids_lockct
);
43 smp_mb__after_atomic_inc();
44 spin_unlock_wait(&ccids_lock
);
47 static inline void ccids_read_unlock(void)
49 atomic_dec(&ccids_lockct
);
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)
59 static struct kmem_cache
*ccid_kmem_cache_create(int obj_size
, const char *fmt
,...)
61 struct kmem_cache
*slab
;
62 char slab_name_fmt
[32], *slab_name
;
66 vsnprintf(slab_name_fmt
, sizeof(slab_name_fmt
), fmt
, args
);
69 slab_name
= kstrdup(slab_name_fmt
, GFP_KERNEL
);
70 if (slab_name
== NULL
)
72 slab
= kmem_cache_create(slab_name
, sizeof(struct ccid
) + obj_size
, 0,
73 SLAB_HWCACHE_ALIGN
, NULL
);
79 static void ccid_kmem_cache_destroy(struct kmem_cache
*slab
)
82 const char *name
= kmem_cache_name(slab
);
84 kmem_cache_destroy(slab
);
89 int ccid_register(struct ccid_operations
*ccid_ops
)
93 ccid_ops
->ccid_hc_rx_slab
=
94 ccid_kmem_cache_create(ccid_ops
->ccid_hc_rx_obj_size
,
97 if (ccid_ops
->ccid_hc_rx_slab
== NULL
)
100 ccid_ops
->ccid_hc_tx_slab
=
101 ccid_kmem_cache_create(ccid_ops
->ccid_hc_tx_obj_size
,
104 if (ccid_ops
->ccid_hc_tx_slab
== NULL
)
105 goto out_free_rx_slab
;
109 if (ccids
[ccid_ops
->ccid_id
] == NULL
) {
110 ccids
[ccid_ops
->ccid_id
] = ccid_ops
;
113 ccids_write_unlock();
115 goto out_free_tx_slab
;
117 pr_info("CCID: Registered CCID %d (%s)\n",
118 ccid_ops
->ccid_id
, ccid_ops
->ccid_name
);
122 ccid_kmem_cache_destroy(ccid_ops
->ccid_hc_tx_slab
);
123 ccid_ops
->ccid_hc_tx_slab
= NULL
;
126 ccid_kmem_cache_destroy(ccid_ops
->ccid_hc_rx_slab
);
127 ccid_ops
->ccid_hc_rx_slab
= NULL
;
131 EXPORT_SYMBOL_GPL(ccid_register
);
133 int ccid_unregister(struct ccid_operations
*ccid_ops
)
136 ccids
[ccid_ops
->ccid_id
] = NULL
;
137 ccids_write_unlock();
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
;
144 pr_info("CCID: Unregistered CCID %d (%s)\n",
145 ccid_ops
->ccid_id
, ccid_ops
->ccid_name
);
149 EXPORT_SYMBOL_GPL(ccid_unregister
);
151 struct ccid
*ccid_new(unsigned char id
, struct sock
*sk
, int rx
, gfp_t gfp
)
153 struct ccid_operations
*ccid_ops
;
154 struct ccid
*ccid
= NULL
;
158 if (ccids
[id
] == NULL
) {
159 /* We only try to load if in process context */
161 if (gfp
& GFP_ATOMIC
)
163 request_module("net-dccp-ccid-%d", id
);
167 ccid_ops
= ccids
[id
];
168 if (ccid_ops
== NULL
)
171 if (!try_module_get(ccid_ops
->ccid_owner
))
176 ccid
= kmem_cache_alloc(rx
? ccid_ops
->ccid_hc_rx_slab
:
177 ccid_ops
->ccid_hc_tx_slab
, gfp
);
180 ccid
->ccid_ops
= ccid_ops
;
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)
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)
198 kmem_cache_free(rx
? ccid_ops
->ccid_hc_rx_slab
:
199 ccid_ops
->ccid_hc_tx_slab
, ccid
);
202 module_put(ccid_ops
->ccid_owner
);
206 EXPORT_SYMBOL_GPL(ccid_new
);
208 struct ccid
*ccid_hc_rx_new(unsigned char id
, struct sock
*sk
, gfp_t gfp
)
210 return ccid_new(id
, sk
, 1, gfp
);
213 EXPORT_SYMBOL_GPL(ccid_hc_rx_new
);
215 struct ccid
*ccid_hc_tx_new(unsigned char id
,struct sock
*sk
, gfp_t gfp
)
217 return ccid_new(id
, sk
, 0, gfp
);
220 EXPORT_SYMBOL_GPL(ccid_hc_tx_new
);
222 static void ccid_delete(struct ccid
*ccid
, struct sock
*sk
, int rx
)
224 struct ccid_operations
*ccid_ops
;
229 ccid_ops
= ccid
->ccid_ops
;
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
);
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
);
240 if (ccids
[ccid_ops
->ccid_id
] != NULL
)
241 module_put(ccid_ops
->ccid_owner
);
245 void ccid_hc_rx_delete(struct ccid
*ccid
, struct sock
*sk
)
247 ccid_delete(ccid
, sk
, 1);
250 EXPORT_SYMBOL_GPL(ccid_hc_rx_delete
);
252 void ccid_hc_tx_delete(struct ccid
*ccid
, struct sock
*sk
)
254 ccid_delete(ccid
, sk
, 0);
257 EXPORT_SYMBOL_GPL(ccid_hc_tx_delete
);