diff options
| -rw-r--r-- | net/tipc/core.c | 3 | ||||
| -rw-r--r-- | net/tipc/subscr.c | 199 | ||||
| -rw-r--r-- | net/tipc/subscr.h | 4 |
3 files changed, 116 insertions, 90 deletions
diff --git a/net/tipc/core.c b/net/tipc/core.c index 6d6aa5a..3d97386 100644 --- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -164,8 +164,7 @@ int tipc_core_start(void) tipc_mode = TIPC_NODE_MODE; if ((res = tipc_handler_start()) || - (res = tipc_ref_table_init(tipc_max_ports + tipc_max_subscriptions, - tipc_random)) || + (res = tipc_ref_table_init(tipc_max_ports, tipc_random)) || (res = tipc_reg_start()) || (res = tipc_nametbl_init()) || (res = tipc_k_signal((Handler)tipc_subscr_start, 0)) || diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c index dde23f1..7c62791 100644 --- a/net/tipc/subscr.c +++ b/net/tipc/subscr.c @@ -38,23 +38,22 @@ #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; }; /** @@ -91,6 +90,9 @@ static u32 htohl(u32 in, int swap) /** * 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, @@ -110,7 +112,7 @@ 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); } /** @@ -163,20 +165,18 @@ void tipc_subscr_report_overlap(struct subscription *sub, 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; } @@ -184,19 +184,21 @@ static void subscr_timeout(struct subscription *sub) 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); @@ -205,7 +207,7 @@ static void subscr_timeout(struct subscription *sub) /** * 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) @@ -219,7 +221,7 @@ 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 @@ -229,14 +231,21 @@ static void subscr_del(struct subscription *sub) 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, @@ -250,27 +259,25 @@ static void subscr_terminate(struct subscriber *subscriber) 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. * @@ -313,11 +320,11 @@ static void subscr_cancel(struct tipc_subscr *s, /** * 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; @@ -331,7 +338,7 @@ static void subscr_subscribe(struct tipc_subscr *s, 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 */ @@ -340,16 +347,16 @@ static void subscr_subscribe(struct tipc_subscr *s, 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 */ @@ -365,40 +372,41 @@ static void subscr_subscribe(struct tipc_subscr *s, 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; @@ -408,6 +416,8 @@ static void subscr_conn_shutdown_event(void *usr_handle, /** * 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, @@ -416,20 +426,46 @@ 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); + } + } } /** @@ -445,16 +481,10 @@ static void subscr_named_msg_event(void *usr_handle, 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 */ @@ -465,18 +495,11 @@ static void subscr_named_msg_event(void *usr_handle, } 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, @@ -488,32 +511,36 @@ static void subscr_named_msg_event(void *usr_handle, &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) @@ -572,8 +599,8 @@ void tipc_subscr_stop(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); } diff --git a/net/tipc/subscr.h b/net/tipc/subscr.h index 3e3e026..b9af687 100644 --- a/net/tipc/subscr.h +++ b/net/tipc/subscr.h @@ -49,12 +49,12 @@ typedef void (*tipc_subscr_event) (struct subscription *sub, * @timeout: duration of subscription (in ms) * @filter: event filtering to be done for subscription * @event_cb: routine invoked when a subscription event is detected + * @server_ref: object reference of server port associated with subscription * @swap: indicates if subscriber uses opposite endianness in its messages * @evt: template for events generated by subscription * @subscription_list: adjacent subscriptions in subscriber's subscription list * @nameseq_list: adjacent subscriptions in name sequence's subscription list * @timer_ref: reference to timer governing subscription duration (may be NULL) - * @owner: pointer to subscriber object associated with this subscription */ struct subscription { @@ -62,12 +62,12 @@ struct subscription { u32 timeout; u32 filter; tipc_subscr_event event_cb; + u32 server_ref; int swap; struct tipc_event evt; struct list_head subscription_list; struct list_head nameseq_list; struct timer_list timer; - struct subscriber *owner; }; int tipc_subscr_overlap(struct subscription * sub, |
