+
+/*
+ * Manage NSM handles
+ */
+static LIST_HEAD(nsm_handles);
+static DEFINE_MUTEX(nsm_mutex);
+
+static struct nsm_handle *
+__nsm_find(const struct sockaddr_in *sin,
+ const char *hostname, int hostname_len,
+ int create)
+{
+ struct nsm_handle *nsm = NULL;
+ struct list_head *pos;
+
+ if (!sin)
+ return NULL;
+
+ if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
+ if (printk_ratelimit()) {
+ printk(KERN_WARNING "Invalid hostname \"%.*s\" "
+ "in NFS lock request\n",
+ hostname_len, hostname);
+ }
+ return NULL;
+ }
+
+ mutex_lock(&nsm_mutex);
+ list_for_each(pos, &nsm_handles) {
+ nsm = list_entry(pos, struct nsm_handle, sm_link);
+
+ if (hostname && nsm_use_hostnames) {
+ if (strlen(nsm->sm_name) != hostname_len
+ || memcmp(nsm->sm_name, hostname, hostname_len))
+ continue;
+ } else if (!nlm_cmp_addr(&nsm->sm_addr, sin))
+ continue;
+ atomic_inc(&nsm->sm_count);
+ goto out;
+ }
+
+ if (!create) {
+ nsm = NULL;
+ goto out;
+ }
+
+ nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
+ if (nsm != NULL) {
+ nsm->sm_addr = *sin;
+ nsm->sm_name = (char *) (nsm + 1);
+ memcpy(nsm->sm_name, hostname, hostname_len);
+ nsm->sm_name[hostname_len] = '\0';
+ atomic_set(&nsm->sm_count, 1);
+
+ list_add(&nsm->sm_link, &nsm_handles);
+ }
+
+out:
+ mutex_unlock(&nsm_mutex);
+ return nsm;
+}
+
+static struct nsm_handle *
+nsm_find(const struct sockaddr_in *sin, const char *hostname, int hostname_len)
+{
+ return __nsm_find(sin, hostname, hostname_len, 1);
+}
+
+/*
+ * Release an NSM handle
+ */
+void
+nsm_release(struct nsm_handle *nsm)
+{
+ if (!nsm)
+ return;
+ if (atomic_dec_and_test(&nsm->sm_count)) {
+ mutex_lock(&nsm_mutex);
+ if (atomic_read(&nsm->sm_count) == 0) {
+ list_del(&nsm->sm_link);
+ kfree(nsm);
+ }
+ mutex_unlock(&nsm_mutex);
+ }
+}