[IA64-SGI] fixes for XPC disengage and open/close protocol
This patch addresses a few issues with the open/close protocol that
were revealed by the newly added disengage functionality combined
with more extensive testing.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/sn/kernel/xpc_channel.c b/arch/ia64/sn/kernel/xpc_channel.c
index 195ac1b..abf4fc2 100644
--- a/arch/ia64/sn/kernel/xpc_channel.c
+++ b/arch/ia64/sn/kernel/xpc_channel.c
@@ -792,11 +792,20 @@
"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);
+
+ } else if (ch->delayed_IPI_flags) {
+ if (part->act_state != XPC_P_DEACTIVATING) {
+ /* time to take action on any delayed IPI flags */
+ spin_lock(&part->IPI_lock);
+ XPC_SET_IPI_FLAGS(part->local_IPI_amo, ch->number,
+ ch->delayed_IPI_flags);
+ spin_unlock(&part->IPI_lock);
+ }
+ ch->delayed_IPI_flags = 0;
}
}
@@ -818,6 +827,19 @@
spin_lock_irqsave(&ch->lock, irq_flags);
+again:
+
+ if ((ch->flags & XPC_C_DISCONNECTED) &&
+ (ch->flags & XPC_C_WDISCONNECT)) {
+ /*
+ * Delay processing IPI flags until thread waiting disconnect
+ * has had a chance to see that the channel is disconnected.
+ */
+ ch->delayed_IPI_flags |= IPI_flags;
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return;
+ }
+
if (IPI_flags & XPC_IPI_CLOSEREQUEST) {
@@ -843,14 +865,22 @@
/* both sides have finished disconnecting */
xpc_process_disconnect(ch, &irq_flags);
+ DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
+ goto again;
}
if (ch->flags & XPC_C_DISCONNECTED) {
- // >>> explain this section
-
if (!(IPI_flags & XPC_IPI_OPENREQUEST)) {
- DBUG_ON(part->act_state !=
- XPC_P_DEACTIVATING);
+ if ((XPC_GET_IPI_FLAGS(part->local_IPI_amo,
+ ch_number) & XPC_IPI_OPENREQUEST)) {
+
+ DBUG_ON(ch->delayed_IPI_flags != 0);
+ spin_lock(&part->IPI_lock);
+ XPC_SET_IPI_FLAGS(part->local_IPI_amo,
+ ch_number,
+ XPC_IPI_CLOSEREQUEST);
+ spin_unlock(&part->IPI_lock);
+ }
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
@@ -880,9 +910,13 @@
}
XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
- } else {
- xpc_process_disconnect(ch, &irq_flags);
+
+ DBUG_ON(IPI_flags & XPC_IPI_CLOSEREPLY);
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return;
}
+
+ xpc_process_disconnect(ch, &irq_flags);
}
@@ -898,7 +932,20 @@
}
DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
- DBUG_ON(!(ch->flags & XPC_C_RCLOSEREQUEST));
+
+ if (!(ch->flags & XPC_C_RCLOSEREQUEST)) {
+ if ((XPC_GET_IPI_FLAGS(part->local_IPI_amo, ch_number)
+ & XPC_IPI_CLOSEREQUEST)) {
+
+ DBUG_ON(ch->delayed_IPI_flags != 0);
+ spin_lock(&part->IPI_lock);
+ XPC_SET_IPI_FLAGS(part->local_IPI_amo,
+ ch_number, XPC_IPI_CLOSEREPLY);
+ spin_unlock(&part->IPI_lock);
+ }
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return;
+ }
ch->flags |= XPC_C_RCLOSEREPLY;
@@ -916,8 +963,14 @@
"channel=%d\n", args->msg_size, args->local_nentries,
ch->partid, ch->number);
- if ((ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) ||
- part->act_state == XPC_P_DEACTIVATING) {
+ if (part->act_state == XPC_P_DEACTIVATING ||
+ (ch->flags & XPC_C_ROPENREQUEST)) {
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return;
+ }
+
+ if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {
+ ch->delayed_IPI_flags |= XPC_IPI_OPENREQUEST;
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
@@ -931,8 +984,11 @@
* msg_size = size of channel's messages in bytes
* local_nentries = remote partition's local_nentries
*/
- DBUG_ON(args->msg_size == 0);
- DBUG_ON(args->local_nentries == 0);
+ if (args->msg_size == 0 || args->local_nentries == 0) {
+ /* assume OPENREQUEST was delayed by mistake */
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return;
+ }
ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
ch->remote_nentries = args->local_nentries;
@@ -970,7 +1026,13 @@
spin_unlock_irqrestore(&ch->lock, irq_flags);
return;
}
- DBUG_ON(!(ch->flags & XPC_C_OPENREQUEST));
+ if (!(ch->flags & XPC_C_OPENREQUEST)) {
+ XPC_DISCONNECT_CHANNEL(ch, xpcOpenCloseError,
+ &irq_flags);
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+ return;
+ }
+
DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
DBUG_ON(ch->flags & XPC_C_CONNECTED);
@@ -1024,8 +1086,8 @@
struct xpc_registration *registration = &xpc_registrations[ch->number];
- if (down_interruptible(®istration->sema) != 0) {
- return xpcInterrupted;
+ if (down_trylock(®istration->sema) != 0) {
+ return xpcRetry;
}
if (!XPC_CHANNEL_REGISTERED(ch->number)) {
@@ -1445,19 +1507,11 @@
if (xpc_part_ref(part)) {
ch = &part->channels[ch_number];
- if (!(ch->flags & XPC_C_DISCONNECTING)) {
- DBUG_ON(ch->flags & XPC_C_OPENREQUEST);
- DBUG_ON(ch->flags & XPC_C_CONNECTED);
- DBUG_ON(ch->flags & XPC_C_SETUP);
-
- /*
- * Initiate the establishment of a connection
- * on the newly registered channel to the
- * remote partition.
- */
- xpc_wakeup_channel_mgr(part);
- }
-
+ /*
+ * Initiate the establishment of a connection on the
+ * newly registered channel to the remote partition.
+ */
+ xpc_wakeup_channel_mgr(part);
xpc_part_deref(part);
}
}
@@ -1467,9 +1521,6 @@
void
xpc_connected_callout(struct xpc_channel *ch)
{
- unsigned long irq_flags;
-
-
/* let the registerer know that a connection has been established */
if (ch->func != NULL) {
@@ -1482,10 +1533,6 @@
dev_dbg(xpc_chan, "ch->func() returned, reason=xpcConnected, "
"partid=%d, channel=%d\n", ch->partid, ch->number);
}
-
- spin_lock_irqsave(&ch->lock, irq_flags);
- ch->flags |= XPC_C_CONNECTCALLOUT;
- spin_unlock_irqrestore(&ch->lock, irq_flags);
}