1 files changed, 115 insertions, 101 deletions

diff --git a/arch/ia64/sn/kernel/xpc_channel.c b/arch/ia64/sn/kernel/xpc_channel.c
index 94698bea7be..195ac1b8e26 100644
--- a/arch/ia64/sn/kernel/xpc_channel.c
+++ b/arch/ia64/sn/kernel/xpc_channel.c
@@ -57,6 +57,7 @@ xpc_initialize_channels(struct xpc_partition *part, partid_t partid)
 
 		spin_lock_init(&ch->lock);
 		sema_init(&ch->msg_to_pull_sema, 1);	/* mutex */
+		sema_init(&ch->wdisconnect_sema, 0);	/* event wait */
 
 		atomic_set(&ch->n_on_msg_allocate_wq, 0);
 		init_waitqueue_head(&ch->msg_allocate_wq);
@@ -166,6 +167,7 @@ xpc_setup_infrastructure(struct xpc_partition *part)
 	xpc_initialize_channels(part, partid);
 
 	atomic_set(&part->nchannels_active, 0);
+	atomic_set(&part->nchannels_engaged, 0);
 
 
 	/* local_IPI_amo were set to 0 by an earlier memset() */
@@ -555,8 +557,6 @@ xpc_allocate_msgqueues(struct xpc_channel *ch)
 		sema_init(&ch->notify_queue[i].sema, 0);
 	}
 
-	sema_init(&ch->teardown_sema, 0);	/* event wait */
-
 	spin_lock_irqsave(&ch->lock, irq_flags);
 	ch->flags |= XPC_C_SETUP;
 	spin_unlock_irqrestore(&ch->lock, irq_flags);
@@ -626,6 +626,55 @@ xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
 
 
 /*
+ * Notify those who wanted to be notified upon delivery of their message.
+ */
+static void
+xpc_notify_senders(struct xpc_channel *ch, enum xpc_retval reason, s64 put)
+{
+	struct xpc_notify *notify;
+	u8 notify_type;
+	s64 get = ch->w_remote_GP.get - 1;
+
+
+	while (++get < put && atomic_read(&ch->n_to_notify) > 0) {
+
+		notify = &ch->notify_queue[get % ch->local_nentries];
+
+		/*
+		 * See if the notify entry indicates it was associated with
+		 * a message who's sender wants to be notified. It is possible
+		 * that it is, but someone else is doing or has done the
+		 * notification.
+		 */
+		notify_type = notify->type;
+		if (notify_type == 0 ||
+				cmpxchg(&notify->type, notify_type, 0) !=
+								notify_type) {
+			continue;
+		}
+
+		DBUG_ON(notify_type != XPC_N_CALL);
+
+		atomic_dec(&ch->n_to_notify);
+
+		if (notify->func != NULL) {
+			dev_dbg(xpc_chan, "notify->func() called, notify=0x%p, "
+				"msg_number=%ld, partid=%d, channel=%d\n",
+				(void *) notify, get, ch->partid, ch->number);
+
+			notify->func(reason, ch->partid, ch->number,
+								notify->key);
+
+			dev_dbg(xpc_chan, "notify->func() returned, "
+				"notify=0x%p, msg_number=%ld, partid=%d, "
+				"channel=%d\n", (void *) notify, get,
+				ch->partid, ch->number);
+		}
+	}
+}
+
+
+/*
  * Free up message queues and other stuff that were allocated for the specified
  * channel.
  *
@@ -669,9 +718,6 @@ xpc_free_msgqueues(struct xpc_channel *ch)
 		ch->remote_msgqueue = NULL;
 		kfree(ch->notify_queue);
 		ch->notify_queue = NULL;
-
-		/* in case someone is waiting for the teardown to complete */
-		up(&ch->teardown_sema);
 	}
 }
 
@@ -683,7 +729,7 @@ static void
 xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
 {
 	struct xpc_partition *part = &xpc_partitions[ch->partid];
-	u32 ch_flags = ch->flags;
+	u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED);
 
 
 	DBUG_ON(!spin_is_locked(&ch->lock));
@@ -701,12 +747,13 @@ xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
 	}
 	DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);
 
-	/* it's now safe to free the channel's message queues */
-
-	xpc_free_msgqueues(ch);
-	DBUG_ON(ch->flags & XPC_C_SETUP);
+	if (part->act_state == XPC_P_DEACTIVATING) {
+		/* can't proceed until the other side disengages from us */
+		if (xpc_partition_engaged(1UL << ch->partid)) {
+			return;
+		}
 
-	if (part->act_state != XPC_P_DEACTIVATING) {
+	} else {
 
 		/* as long as the other side is up do the full protocol */
 
@@ -724,16 +771,33 @@ xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
 		}
 	}
 
+	/* wake those waiting for notify completion */
+	if (atomic_read(&ch->n_to_notify) > 0) {
+		/* >>> we do callout while holding ch->lock */
+		xpc_notify_senders(ch, ch->reason, ch->w_local_GP.put);
+	}
+
 	/* both sides are disconnected now */
 
-	ch->flags = XPC_C_DISCONNECTED;	/* clear all flags, but this one */
+	/* it's now safe to free the channel's message queues */
+	xpc_free_msgqueues(ch);
+
+	/* mark disconnected, clear all other flags except XPC_C_WDISCONNECT */
+	ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT));
 
 	atomic_dec(&part->nchannels_active);
 
-	if (ch_flags & XPC_C_WASCONNECTED) {
+	if (channel_was_connected) {
 		dev_info(xpc_chan, "channel %d to partition %d disconnected, "
 			"reason=%d\n", ch->number, ch->partid, ch->reason);
 	}
+
+	/* wake the thread that is waiting for this channel to disconnect */
+	if (ch->flags & XPC_C_WDISCONNECT) {
+		spin_unlock_irqrestore(&ch->lock, *irq_flags);
+		up(&ch->wdisconnect_sema);
+		spin_lock_irqsave(&ch->lock, *irq_flags);
+	}
 }
 
 
@@ -764,7 +828,7 @@ xpc_process_openclose_IPI(struct xpc_partition *part, int ch_number,
 		/*
 		 * If RCLOSEREQUEST is set, we're probably waiting for
 		 * RCLOSEREPLY. We should find it and a ROPENREQUEST packed
-		 * with this RCLOSEQREUQEST in the IPI_flags.
+		 * with this RCLOSEREQUEST in the IPI_flags.
 		 */
 
 		if (ch->flags & XPC_C_RCLOSEREQUEST) {
@@ -852,7 +916,7 @@ xpc_process_openclose_IPI(struct xpc_partition *part, int ch_number,
 			"channel=%d\n", args->msg_size, args->local_nentries,
 			ch->partid, ch->number);
 
-		if ((ch->flags & XPC_C_DISCONNECTING) ||
+		if ((ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) ||
 					part->act_state == XPC_P_DEACTIVATING) {
 			spin_unlock_irqrestore(&ch->lock, irq_flags);
 			return;
@@ -1040,55 +1104,6 @@ xpc_connect_channel(struct xpc_channel *ch)
 
 
 /*
- * Notify those who wanted to be notified upon delivery of their message.
- */
-static void
-xpc_notify_senders(struct xpc_channel *ch, enum xpc_retval reason, s64 put)
-{
-	struct xpc_notify *notify;
-	u8 notify_type;
-	s64 get = ch->w_remote_GP.get - 1;
-
-
-	while (++get < put && atomic_read(&ch->n_to_notify) > 0) {
-
-		notify = &ch->notify_queue[get % ch->local_nentries];
-
-		/*
-		 * See if the notify entry indicates it was associated with
-		 * a message who's sender wants to be notified. It is possible
-		 * that it is, but someone else is doing or has done the
-		 * notification.
-		 */
-		notify_type = notify->type;
-		if (notify_type == 0 ||
-				cmpxchg(&notify->type, notify_type, 0) !=
-								notify_type) {
-			continue;
-		}
-
-		DBUG_ON(notify_type != XPC_N_CALL);
-
-		atomic_dec(&ch->n_to_notify);
-
-		if (notify->func != NULL) {
-			dev_dbg(xpc_chan, "notify->func() called, notify=0x%p, "
-				"msg_number=%ld, partid=%d, channel=%d\n",
-				(void *) notify, get, ch->partid, ch->number);
-
-			notify->func(reason, ch->partid, ch->number,
-								notify->key);
-
-			dev_dbg(xpc_chan, "notify->func() returned, "
-				"notify=0x%p, msg_number=%ld, partid=%d, "
-				"channel=%d\n", (void *) notify, get,
-				ch->partid, ch->number);
-		}
-	}
-}
-
-
-/*
  * Clear some of the msg flags in the local message queue.
  */
 static inline void
@@ -1240,6 +1255,7 @@ xpc_process_channel_activity(struct xpc_partition *part)
 	u64 IPI_amo, IPI_flags;
 	struct xpc_channel *ch;
 	int ch_number;
+	u32 ch_flags;
 
 
 	IPI_amo = xpc_get_IPI_flags(part);
@@ -1266,8 +1282,9 @@ xpc_process_channel_activity(struct xpc_partition *part)
 			xpc_process_openclose_IPI(part, ch_number, IPI_flags);
 		}
 
+		ch_flags = ch->flags;	/* need an atomic snapshot of flags */
 
-		if (ch->flags & XPC_C_DISCONNECTING) {
+		if (ch_flags & XPC_C_DISCONNECTING) {
 			spin_lock_irqsave(&ch->lock, irq_flags);
 			xpc_process_disconnect(ch, &irq_flags);
 			spin_unlock_irqrestore(&ch->lock, irq_flags);
@@ -1278,9 +1295,9 @@ xpc_process_channel_activity(struct xpc_partition *part)
 			continue;
 		}
 
-		if (!(ch->flags & XPC_C_CONNECTED)) {
-			if (!(ch->flags & XPC_C_OPENREQUEST)) {
-				DBUG_ON(ch->flags & XPC_C_SETUP);
+		if (!(ch_flags & XPC_C_CONNECTED)) {
+			if (!(ch_flags & XPC_C_OPENREQUEST)) {
+				DBUG_ON(ch_flags & XPC_C_SETUP);
 				(void) xpc_connect_channel(ch);
 			} else {
 				spin_lock_irqsave(&ch->lock, irq_flags);
@@ -1305,8 +1322,8 @@ xpc_process_channel_activity(struct xpc_partition *part)
 
 
 /*
- * XPC's heartbeat code calls this function to inform XPC that a partition has
- * gone down.  XPC responds by tearing down the XPartition Communication
+ * XPC's heartbeat code calls this function to inform XPC that a partition is
+ * going down.  XPC responds by tearing down the XPartition Communication
  * infrastructure used for the just downed partition.
  *
  * XPC's heartbeat code will never call this function and xpc_partition_up()
@@ -1314,7 +1331,7 @@ xpc_process_channel_activity(struct xpc_partition *part)
  * at the same time.
  */
 void
-xpc_partition_down(struct xpc_partition *part, enum xpc_retval reason)
+xpc_partition_going_down(struct xpc_partition *part, enum xpc_retval reason)
 {
 	unsigned long irq_flags;
 	int ch_number;
@@ -1330,12 +1347,11 @@ xpc_partition_down(struct xpc_partition *part, enum xpc_retval reason)
 	}
 
 
-	/* disconnect all channels associated with the downed partition */
+	/* disconnect channels associated with the partition going down */
 
 	for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
 		ch = &part->channels[ch_number];
 
-
 		xpc_msgqueue_ref(ch);
 		spin_lock_irqsave(&ch->lock, irq_flags);
 
@@ -1370,6 +1386,7 @@ xpc_teardown_infrastructure(struct xpc_partition *part)
 	 * this partition.
 	 */
 
+	DBUG_ON(atomic_read(&part->nchannels_engaged) != 0);
 	DBUG_ON(atomic_read(&part->nchannels_active) != 0);
 	DBUG_ON(part->setup_state != XPC_P_SETUP);
 	part->setup_state = XPC_P_WTEARDOWN;
@@ -1506,8 +1523,12 @@ xpc_initiate_disconnect(int ch_number)
 
 			spin_lock_irqsave(&ch->lock, irq_flags);
 
-			XPC_DISCONNECT_CHANNEL(ch, xpcUnregistering,
+			if (!(ch->flags & XPC_C_DISCONNECTED)) {
+				ch->flags |= XPC_C_WDISCONNECT;
+
+				XPC_DISCONNECT_CHANNEL(ch, xpcUnregistering,
 								&irq_flags);
+			}
 
 			spin_unlock_irqrestore(&ch->lock, irq_flags);
 
@@ -1523,8 +1544,9 @@ xpc_initiate_disconnect(int ch_number)
 /*
  * To disconnect a channel, and reflect it back to all who may be waiting.
  *
- * >>> An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by
- * >>> xpc_free_msgqueues().
+ * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by
+ * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by
+ * xpc_disconnect_wait().
  *
  * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.
  */
@@ -1532,7 +1554,7 @@ void
 xpc_disconnect_channel(const int line, struct xpc_channel *ch,
 			enum xpc_retval reason, unsigned long *irq_flags)
 {
-	u32 flags;
+	u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED);
 
 
 	DBUG_ON(!spin_is_locked(&ch->lock));
@@ -1547,61 +1569,53 @@ xpc_disconnect_channel(const int line, struct xpc_channel *ch,
 
 	XPC_SET_REASON(ch, reason, line);
 
-	flags = ch->flags;
+	ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
 	/* some of these may not have been set */
 	ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY |
 			XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
 			XPC_C_CONNECTING | XPC_C_CONNECTED);
 
-	ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
 	xpc_IPI_send_closerequest(ch, irq_flags);
 
-	if (flags & XPC_C_CONNECTED) {
+	if (channel_was_connected) {
 		ch->flags |= XPC_C_WASCONNECTED;
 	}
 
+	spin_unlock_irqrestore(&ch->lock, *irq_flags);
+
+	/* wake all idle kthreads so they can exit */
 	if (atomic_read(&ch->kthreads_idle) > 0) {
-		/* wake all idle kthreads so they can exit */
 		wake_up_all(&ch->idle_wq);
 	}
 
-	spin_unlock_irqrestore(&ch->lock, *irq_flags);
-
-
 	/* wake those waiting to allocate an entry from the local msg queue */
-
 	if (atomic_read(&ch->n_on_msg_allocate_wq) > 0) {
 		wake_up(&ch->msg_allocate_wq);
 	}
 
-	/* wake those waiting for notify completion */
-
-	if (atomic_read(&ch->n_to_notify) > 0) {
-		xpc_notify_senders(ch, reason, ch->w_local_GP.put);
-	}
-
 	spin_lock_irqsave(&ch->lock, *irq_flags);
 }
 
 
 void
-xpc_disconnected_callout(struct xpc_channel *ch)
+xpc_disconnecting_callout(struct xpc_channel *ch)
 {
 	/*
-	 * Let the channel's registerer know that the channel is now
+	 * Let the channel's registerer know that the channel is being
 	 * disconnected. We don't want to do this if the registerer was never
-	 * informed of a connection being made, unless the disconnect was for
-	 * abnormal reasons.
+	 * informed of a connection being made.
 	 */
 
 	if (ch->func != NULL) {
-		dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "
-			"channel=%d\n", ch->reason, ch->partid, ch->number);
+		dev_dbg(xpc_chan, "ch->func() called, reason=xpcDisconnecting,"
+			" partid=%d, channel=%d\n", ch->partid, ch->number);
 
-		ch->func(ch->reason, ch->partid, ch->number, NULL, ch->key);
+		ch->func(xpcDisconnecting, ch->partid, ch->number, NULL,
+								ch->key);
 
-		dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "
-			"channel=%d\n", ch->reason, ch->partid, ch->number);
+		dev_dbg(xpc_chan, "ch->func() returned, reason="
+			"xpcDisconnecting, partid=%d, channel=%d\n",
+			ch->partid, ch->number);
 	}
 }
 
@@ -1848,7 +1862,7 @@ xpc_send_msg(struct xpc_channel *ch, struct xpc_msg *msg, u8 notify_type,
 			xpc_notify_func func, void *key)
 {
 	enum xpc_retval ret = xpcSuccess;
-	struct xpc_notify *notify = NULL;   // >>> to keep the compiler happy!!
+	struct xpc_notify *notify = notify;
 	s64 put, msg_number = msg->number;