#include "dbg.h"
#include "subscr.h"
#include "name_table.h"
+#include "port.h"
#include "ref.h"
/**
* struct subscriber - TIPC network topology subscriber
- * @ref: object reference to subscriber object itself
- * @lock: pointer to spinlock controlling access to subscriber object
+ * @port_ref: object reference to server port connecting to subscriber
+ * @lock: pointer to spinlock controlling access to subscriber's server port
* @subscriber_list: adjacent subscribers in top. server's list of subscribers
* @subscription_list: list of subscription objects for this subscriber
- * @port_ref: object reference to port used to communicate with subscriber
*/
struct subscriber {
- u32 ref;
+ u32 port_ref;
spinlock_t *lock;
struct list_head subscriber_list;
struct list_head subscription_list;
- u32 port_ref;
};
/**
/**
* subscr_send_event - send a message containing a tipc_event to the subscriber
+ *
+ * Note: Must not hold subscriber's server port lock, since tipc_send() will
+ * try to take the lock if the message is rejected and returned!
*/
static void subscr_send_event(struct subscription *sub,
sub->evt.found_upper = htohl(found_upper, sub->swap);
sub->evt.port.ref = htohl(port_ref, sub->swap);
sub->evt.port.node = htohl(node, sub->swap);
- tipc_send(sub->owner->port_ref, 1, &msg_sect);
+ tipc_send(sub->server_ref, 1, &msg_sect);
}
/**
static void subscr_timeout(struct subscription *sub)
{
- struct subscriber *subscriber;
- u32 subscriber_ref;
+ struct port *server_port;
- /* Validate subscriber reference (in case subscriber is terminating) */
+ /* Validate server port reference (in case subscriber is terminating) */
- subscriber_ref = sub->owner->ref;
- subscriber = (struct subscriber *)tipc_ref_lock(subscriber_ref);
- if (subscriber == NULL)
+ server_port = tipc_port_lock(sub->server_ref);
+ if (server_port == NULL)
return;
/* Validate timeout (in case subscription is being cancelled) */
if (sub->timeout == TIPC_WAIT_FOREVER) {
- tipc_ref_unlock(subscriber_ref);
+ tipc_port_unlock(server_port);
return;
}
tipc_nametbl_unsubscribe(sub);
- /* Notify subscriber of timeout, then unlink subscription */
+ /* Unlink subscription from subscriber */
- subscr_send_event(sub,
- sub->evt.s.seq.lower,
- sub->evt.s.seq.upper,
- TIPC_SUBSCR_TIMEOUT,
- 0,
- 0);
list_del(&sub->subscription_list);
+ /* Release subscriber's server port */
+
+ tipc_port_unlock(server_port);
+
+ /* Notify subscriber of timeout */
+
+ subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
+ TIPC_SUBSCR_TIMEOUT, 0, 0);
+
/* Now destroy subscription */
- tipc_ref_unlock(subscriber_ref);
k_term_timer(&sub->timer);
kfree(sub);
atomic_dec(&topsrv.subscription_count);
/**
* subscr_del - delete a subscription within a subscription list
*
- * Called with subscriber locked.
+ * Called with subscriber port locked.
*/
static void subscr_del(struct subscription *sub)
/**
* subscr_terminate - terminate communication with a subscriber
*
- * Called with subscriber locked. Routine must temporarily release this lock
+ * Called with subscriber port locked. Routine must temporarily release lock
* to enable subscription timeout routine(s) to finish without deadlocking;
* the lock is then reclaimed to allow caller to release it upon return.
* (This should work even in the unlikely event some other thread creates
static void subscr_terminate(struct subscriber *subscriber)
{
+ u32 port_ref;
struct subscription *sub;
struct subscription *sub_temp;
/* Invalidate subscriber reference */
- tipc_ref_discard(subscriber->ref);
+ port_ref = subscriber->port_ref;
+ subscriber->port_ref = 0;
spin_unlock_bh(subscriber->lock);
+ /* Sever connection to subscriber */
+
+ tipc_shutdown(port_ref);
+ tipc_deleteport(port_ref);
+
/* Destroy any existing subscriptions for subscriber */
list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
subscr_del(sub);
}
- /* Sever connection to subscriber */
-
- tipc_shutdown(subscriber->port_ref);
- tipc_deleteport(subscriber->port_ref);
-
/* Remove subscriber from topology server's subscriber list */
spin_lock_bh(&topsrv.lock);
list_del(&subscriber->subscriber_list);
spin_unlock_bh(&topsrv.lock);
- /* Now destroy subscriber */
+ /* Reclaim subscriber lock */
spin_lock_bh(subscriber->lock);
+
+ /* Now destroy subscriber */
+
kfree(subscriber);
}
/**
* subscr_cancel - handle subscription cancellation request
*
- * Called with subscriber locked. Routine must temporarily release this lock
+ * Called with subscriber port locked. Routine must temporarily release lock
* to enable the subscription timeout routine to finish without deadlocking;
* the lock is then reclaimed to allow caller to release it upon return.
*
/**
* subscr_subscribe - create subscription for subscriber
*
- * Called with subscriber locked
+ * Called with subscriber port locked.
*/
-static void subscr_subscribe(struct tipc_subscr *s,
- struct subscriber *subscriber)
+static struct subscription *subscr_subscribe(struct tipc_subscr *s,
+ struct subscriber *subscriber)
{
struct subscription *sub;
int swap;
if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
subscr_cancel(s, subscriber);
- return;
+ return NULL;
}
/* Refuse subscription if global limit exceeded */
warn("Subscription rejected, subscription limit reached (%u)\n",
tipc_max_subscriptions);
subscr_terminate(subscriber);
- return;
+ return NULL;
}
/* Allocate subscription object */
- sub = kzalloc(sizeof(*sub), GFP_ATOMIC);
+ sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
if (!sub) {
warn("Subscription rejected, no memory\n");
subscr_terminate(subscriber);
- return;
+ return NULL;
}
/* Initialize subscription object */
warn("Subscription rejected, illegal request\n");
kfree(sub);
subscr_terminate(subscriber);
- return;
+ return NULL;
}
sub->event_cb = subscr_send_event;
- memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
- INIT_LIST_HEAD(&sub->subscription_list);
INIT_LIST_HEAD(&sub->nameseq_list);
list_add(&sub->subscription_list, &subscriber->subscription_list);
+ sub->server_ref = subscriber->port_ref;
sub->swap = swap;
+ memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
atomic_inc(&topsrv.subscription_count);
if (sub->timeout != TIPC_WAIT_FOREVER) {
k_init_timer(&sub->timer,
(Handler)subscr_timeout, (unsigned long)sub);
k_start_timer(&sub->timer, sub->timeout);
}
- sub->owner = subscriber;
- tipc_nametbl_subscribe(sub);
+
+ return sub;
}
/**
* subscr_conn_shutdown_event - handle termination request from subscriber
+ *
+ * Called with subscriber's server port unlocked.
*/
static void subscr_conn_shutdown_event(void *usr_handle,
- u32 portref,
+ u32 port_ref,
struct sk_buff **buf,
unsigned char const *data,
unsigned int size,
int reason)
{
- struct subscriber *subscriber;
+ struct subscriber *subscriber = usr_handle;
spinlock_t *subscriber_lock;
- subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
- if (subscriber == NULL)
+ if (tipc_port_lock(port_ref) == NULL)
return;
subscriber_lock = subscriber->lock;
/**
* subscr_conn_msg_event - handle new subscription request from subscriber
+ *
+ * Called with subscriber's server port unlocked.
*/
static void subscr_conn_msg_event(void *usr_handle,
const unchar *data,
u32 size)
{
- struct subscriber *subscriber;
+ struct subscriber *subscriber = usr_handle;
spinlock_t *subscriber_lock;
+ struct subscription *sub;
+
+ /*
+ * Lock subscriber's server port (& make a local copy of lock pointer,
+ * in case subscriber is deleted while processing subscription request)
+ */
- subscriber = tipc_ref_lock((u32)(unsigned long)usr_handle);
- if (subscriber == NULL)
+ if (tipc_port_lock(port_ref) == NULL)
return;
subscriber_lock = subscriber->lock;
- if (size != sizeof(struct tipc_subscr))
- subscr_terminate(subscriber);
- else
- subscr_subscribe((struct tipc_subscr *)data, subscriber);
- spin_unlock_bh(subscriber_lock);
+ if (size != sizeof(struct tipc_subscr)) {
+ subscr_terminate(subscriber);
+ spin_unlock_bh(subscriber_lock);
+ } else {
+ sub = subscr_subscribe((struct tipc_subscr *)data, subscriber);
+ spin_unlock_bh(subscriber_lock);
+ if (sub != NULL) {
+
+ /*
+ * We must release the server port lock before adding a
+ * subscription to the name table since TIPC needs to be
+ * able to (re)acquire the port lock if an event message
+ * issued by the subscription process is rejected and
+ * returned. The subscription cannot be deleted while
+ * it is being added to the name table because:
+ * a) the single-threading of the native API port code
+ * ensures the subscription cannot be cancelled and
+ * the subscriber connection cannot be broken, and
+ * b) the name table lock ensures the subscription
+ * timeout code cannot delete the subscription,
+ * so the subscription object is still protected.
+ */
+
+ tipc_nametbl_subscribe(sub);
+ }
+ }
}
/**
struct tipc_portid const *orig,
struct tipc_name_seq const *dest)
{
- struct subscriber *subscriber;
- struct iovec msg_sect = {NULL, 0};
- spinlock_t *subscriber_lock;
+ static struct iovec msg_sect = {NULL, 0};
- dbg("subscr_named_msg_event: orig = %x own = %x,\n",
- orig->node, tipc_own_addr);
- if (size && (size != sizeof(struct tipc_subscr))) {
- warn("Subscriber rejected, invalid subscription size\n");
- return;
- }
+ struct subscriber *subscriber;
+ u32 server_port_ref;
/* Create subscriber object */
}
INIT_LIST_HEAD(&subscriber->subscription_list);
INIT_LIST_HEAD(&subscriber->subscriber_list);
- subscriber->ref = tipc_ref_acquire(subscriber, &subscriber->lock);
- if (subscriber->ref == 0) {
- warn("Subscriber rejected, reference table exhausted\n");
- kfree(subscriber);
- return;
- }
- spin_unlock_bh(subscriber->lock);
- /* Establish a connection to subscriber */
+ /* Create server port & establish connection to subscriber */
tipc_createport(topsrv.user_ref,
- (void *)(unsigned long)subscriber->ref,
+ subscriber,
importance,
NULL,
NULL,
&subscriber->port_ref);
if (subscriber->port_ref == 0) {
warn("Subscriber rejected, unable to create port\n");
- tipc_ref_discard(subscriber->ref);
kfree(subscriber);
return;
}
tipc_connect2port(subscriber->port_ref, orig);
+ /* Lock server port (& save lock address for future use) */
+
+ subscriber->lock = tipc_port_lock(subscriber->port_ref)->publ.lock;
/* Add subscriber to topology server's subscriber list */
- tipc_ref_lock(subscriber->ref);
spin_lock_bh(&topsrv.lock);
list_add(&subscriber->subscriber_list, &topsrv.subscriber_list);
spin_unlock_bh(&topsrv.lock);
- /*
- * Subscribe now if message contains a subscription,
- * otherwise send an empty response to complete connection handshaking
- */
+ /* Unlock server port */
- subscriber_lock = subscriber->lock;
- if (size)
- subscr_subscribe((struct tipc_subscr *)data, subscriber);
- else
- tipc_send(subscriber->port_ref, 1, &msg_sect);
+ server_port_ref = subscriber->port_ref;
+ spin_unlock_bh(subscriber->lock);
- spin_unlock_bh(subscriber_lock);
+ /* Send an ACK- to complete connection handshaking */
+
+ tipc_send(server_port_ref, 1, &msg_sect);
+
+ /* Handle optional subscription request */
+
+ if (size != 0) {
+ subscr_conn_msg_event(subscriber, server_port_ref,
+ buf, data, size);
+ }
}
int tipc_subscr_start(void)
list_for_each_entry_safe(subscriber, subscriber_temp,
&topsrv.subscriber_list,
subscriber_list) {
- tipc_ref_lock(subscriber->ref);
subscriber_lock = subscriber->lock;
+ spin_lock_bh(subscriber_lock);
subscr_terminate(subscriber);
spin_unlock_bh(subscriber_lock);
}
projects / linux-2.6 / commitdiff