From: Lijun Chen [EMAIL PROTECTED]
This patch allows a TIPC application to cancel an existing
topology service subscription by re-requesting the subscription
with the TIPC_SUB_CANCEL filter bit set. (All other bits of
the cancel request must match the original subscription request.)
Signed-off-by: Allan Stephens [EMAIL PROTECTED]
Signed-off-by: Per Liden [EMAIL PROTECTED]
---
include/linux/tipc.h |1 +
net/tipc/subscr.c| 99 ++
2 files changed, 85 insertions(+), 15 deletions(-)
diff --git a/include/linux/tipc.h b/include/linux/tipc.h
index 243a15f..bea4694 100644
--- a/include/linux/tipc.h
+++ b/include/linux/tipc.h
@@ -129,6 +129,7 @@ #define TIPC_CONN_SHUTDOWN 5
#define TIPC_SUB_PORTS 0x01/* filter for port availability */
#define TIPC_SUB_SERVICE 0x02/* filter for service availability */
+#define TIPC_SUB_CANCEL 0x04/* cancel a subscription */
#if 0
/* The following filter options are not currently implemented */
#define TIPC_SUB_NO_BIND_EVTS 0x04/* filter out publish events */
diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
index c51600b..77a87c2 100644
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -155,7 +155,7 @@ void tipc_subscr_report_overlap(struct s
sub-seq.upper, found_lower, found_upper);
if (!tipc_subscr_overlap(sub, found_lower, found_upper))
return;
- if (!must (sub-filter != TIPC_SUB_PORTS))
+ if (!must !(sub-filter TIPC_SUB_PORTS))
return;
subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
}
@@ -176,6 +176,13 @@ static void subscr_timeout(struct subscr
if (subscriber == NULL)
return;
+ /* Validate timeout (in case subscription is being cancelled) */
+
+ if (sub-timeout == TIPC_WAIT_FOREVER) {
+ tipc_ref_unlock(subscriber_ref);
+ return;
+ }
+
/* Unlink subscription from name table */
tipc_nametbl_unsubscribe(sub);
@@ -199,6 +206,20 @@ static void subscr_timeout(struct subscr
}
/**
+ * subscr_del - delete a subscription within a subscription list
+ *
+ * Called with subscriber locked.
+ */
+
+static void subscr_del(struct subscription *sub)
+{
+ tipc_nametbl_unsubscribe(sub);
+ list_del(sub-subscription_list);
+ kfree(sub);
+ atomic_dec(topsrv.subscription_count);
+}
+
+/**
* subscr_terminate - terminate communication with a subscriber
*
* Called with subscriber locked. Routine must temporarily release this lock
@@ -227,12 +248,9 @@ static void subscr_terminate(struct subs
k_cancel_timer(sub-timer);
k_term_timer(sub-timer);
}
- tipc_nametbl_unsubscribe(sub);
- list_del(sub-subscription_list);
- dbg(Term: Removed sub %u,%u,%u from subscriber %x list\n,
+ dbg(Term: Removing sub %u,%u,%u from subscriber %x list\n,
sub-seq.type, sub-seq.lower, sub-seq.upper, subscriber);
- kfree(sub);
- atomic_dec(topsrv.subscription_count);
+ subscr_del(sub);
}
/* Sever connection to subscriber */
@@ -253,6 +271,49 @@ static void subscr_terminate(struct subs
}
/**
+ * subscr_cancel - handle subscription cancellation request
+ *
+ * Called with subscriber locked. Routine must temporarily release this lock
+ * to enable the subscription timeout routine to finish without deadlocking;
+ * the lock is then reclaimed to allow caller to release it upon return.
+ *
+ * Note that fields of 's' use subscriber's endianness!
+ */
+
+static void subscr_cancel(struct tipc_subscr *s,
+ struct subscriber *subscriber)
+{
+ struct subscription *sub;
+ struct subscription *sub_temp;
+ int found = 0;
+
+ /* Find first matching subscription, exit if not found */
+
+ list_for_each_entry_safe(sub, sub_temp, subscriber-subscription_list,
+subscription_list) {
+ if (!memcmp(s, sub-evt.s, sizeof(struct tipc_subscr))) {
+ found = 1;
+ break;
+ }
+ }
+ if (!found)
+ return;
+
+ /* Cancel subscription timer (if used), then delete subscription */
+
+ if (sub-timeout != TIPC_WAIT_FOREVER) {
+ sub-timeout = TIPC_WAIT_FOREVER;
+ spin_unlock_bh(subscriber-lock);
+ k_cancel_timer(sub-timer);
+ k_term_timer(sub-timer);
+ spin_lock_bh(subscriber-lock);
+ }
+ dbg(Cancel: removing sub %u,%u,%u from subscriber %x list\n,
+ sub-seq.type, sub-seq.lower, sub-seq.upper, subscriber);
+ subscr_del(sub);
+}
+
+/**
* subscr_subscribe - create subscription for subscriber
*
* Called with subscriber locked
@@ -263,6
