--- /dev/null
+/*
+ * 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);
git://git.onelab.eu / linux-2.6.git / blobdiff