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-rw-r--r--arch/ia64/sn/kernel/xpc_channel.c15
-rw-r--r--arch/ia64/sn/kernel/xpc_main.c64
-rw-r--r--include/asm-ia64/sn/xpc.h2
3 files changed, 54 insertions, 27 deletions
diff --git a/arch/ia64/sn/kernel/xpc_channel.c b/arch/ia64/sn/kernel/xpc_channel.c
index 1f35408..c08db9c 100644
--- a/arch/ia64/sn/kernel/xpc_channel.c
+++ b/arch/ia64/sn/kernel/xpc_channel.c
@@ -632,7 +632,7 @@ xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
ch->number, ch->partid);
spin_unlock_irqrestore(&ch->lock, *irq_flags);
- xpc_create_kthreads(ch, 1);
+ xpc_create_kthreads(ch, 1, 0);
spin_lock_irqsave(&ch->lock, *irq_flags);
}
@@ -754,12 +754,12 @@ xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
/* make sure all activity has settled down first */
- if (atomic_read(&ch->references) > 0 ||
- ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
- !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE))) {
+ if (atomic_read(&ch->kthreads_assigned) > 0 ||
+ atomic_read(&ch->references) > 0) {
return;
}
- DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);
+ DBUG_ON((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
+ !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE));
if (part->act_state == XPC_P_DEACTIVATING) {
/* can't proceed until the other side disengages from us */
@@ -1651,6 +1651,11 @@ xpc_disconnect_channel(const int line, struct xpc_channel *ch,
/* wake all idle kthreads so they can exit */
if (atomic_read(&ch->kthreads_idle) > 0) {
wake_up_all(&ch->idle_wq);
+
+ } else if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
+ !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
+ /* start a kthread that will do the xpcDisconnecting callout */
+ xpc_create_kthreads(ch, 1, 1);
}
/* wake those waiting to allocate an entry from the local msg queue */
diff --git a/arch/ia64/sn/kernel/xpc_main.c b/arch/ia64/sn/kernel/xpc_main.c
index fa96dfc..7a387d2 100644
--- a/arch/ia64/sn/kernel/xpc_main.c
+++ b/arch/ia64/sn/kernel/xpc_main.c
@@ -681,7 +681,7 @@ xpc_activate_kthreads(struct xpc_channel *ch, int needed)
dev_dbg(xpc_chan, "create %d new kthreads, partid=%d, channel=%d\n",
needed, ch->partid, ch->number);
- xpc_create_kthreads(ch, needed);
+ xpc_create_kthreads(ch, needed, 0);
}
@@ -775,26 +775,28 @@ xpc_daemonize_kthread(void *args)
xpc_kthread_waitmsgs(part, ch);
}
- if (atomic_dec_return(&ch->kthreads_assigned) == 0) {
- spin_lock_irqsave(&ch->lock, irq_flags);
- if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
- !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
- ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
- spin_unlock_irqrestore(&ch->lock, irq_flags);
+ /* let registerer know that connection is disconnecting */
- xpc_disconnect_callout(ch, xpcDisconnecting);
-
- spin_lock_irqsave(&ch->lock, irq_flags);
- ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
- }
+ spin_lock_irqsave(&ch->lock, irq_flags);
+ if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
+ !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
+ ch->flags |= XPC_C_DISCONNECTINGCALLOUT;
spin_unlock_irqrestore(&ch->lock, irq_flags);
+
+ xpc_disconnect_callout(ch, xpcDisconnecting);
+
+ spin_lock_irqsave(&ch->lock, irq_flags);
+ ch->flags |= XPC_C_DISCONNECTINGCALLOUT_MADE;
+ }
+ spin_unlock_irqrestore(&ch->lock, irq_flags);
+
+ if (atomic_dec_return(&ch->kthreads_assigned) == 0) {
if (atomic_dec_return(&part->nchannels_engaged) == 0) {
xpc_mark_partition_disengaged(part);
xpc_IPI_send_disengage(part);
}
}
-
xpc_msgqueue_deref(ch);
dev_dbg(xpc_chan, "kthread exiting, partid=%d, channel=%d\n",
@@ -818,7 +820,8 @@ xpc_daemonize_kthread(void *args)
* partition.
*/
void
-xpc_create_kthreads(struct xpc_channel *ch, int needed)
+xpc_create_kthreads(struct xpc_channel *ch, int needed,
+ int ignore_disconnecting)
{
unsigned long irq_flags;
pid_t pid;
@@ -833,16 +836,38 @@ xpc_create_kthreads(struct xpc_channel *ch, int needed)
* kthread. That kthread is responsible for doing the
* counterpart to the following before it exits.
*/
+ if (ignore_disconnecting) {
+ if (!atomic_inc_not_zero(&ch->kthreads_assigned)) {
+ /* kthreads assigned had gone to zero */
+ BUG_ON(!(ch->flags &
+ XPC_C_DISCONNECTINGCALLOUT_MADE));
+ break;
+ }
+
+ } else if (ch->flags & XPC_C_DISCONNECTING) {
+ break;
+
+ } else if (atomic_inc_return(&ch->kthreads_assigned) == 1) {
+ if (atomic_inc_return(&part->nchannels_engaged) == 1)
+ xpc_mark_partition_engaged(part);
+ }
(void) xpc_part_ref(part);
xpc_msgqueue_ref(ch);
- if (atomic_inc_return(&ch->kthreads_assigned) == 1 &&
- atomic_inc_return(&part->nchannels_engaged) == 1) {
- xpc_mark_partition_engaged(part);
- }
pid = kernel_thread(xpc_daemonize_kthread, (void *) args, 0);
if (pid < 0) {
/* the fork failed */
+
+ /*
+ * NOTE: if (ignore_disconnecting &&
+ * !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) is true,
+ * then we'll deadlock if all other kthreads assigned
+ * to this channel are blocked in the channel's
+ * registerer, because the only thing that will unblock
+ * them is the xpcDisconnecting callout that this
+ * failed kernel_thread would have made.
+ */
+
if (atomic_dec_return(&ch->kthreads_assigned) == 0 &&
atomic_dec_return(&part->nchannels_engaged) == 0) {
xpc_mark_partition_disengaged(part);
@@ -857,9 +882,6 @@ xpc_create_kthreads(struct xpc_channel *ch, int needed)
* Flag this as an error only if we have an
* insufficient #of kthreads for the channel
* to function.
- *
- * No xpc_msgqueue_ref() is needed here since
- * the channel mgr is doing this.
*/
spin_lock_irqsave(&ch->lock, irq_flags);
XPC_DISCONNECT_CHANNEL(ch, xpcLackOfResources,
diff --git a/include/asm-ia64/sn/xpc.h b/include/asm-ia64/sn/xpc.h
index 1d45e15..e52b850 100644
--- a/include/asm-ia64/sn/xpc.h
+++ b/include/asm-ia64/sn/xpc.h
@@ -673,7 +673,7 @@ extern irqreturn_t xpc_notify_IRQ_handler(int, void *);
extern void xpc_dropped_IPI_check(struct xpc_partition *);
extern void xpc_activate_partition(struct xpc_partition *);
extern void xpc_activate_kthreads(struct xpc_channel *, int);
-extern void xpc_create_kthreads(struct xpc_channel *, int);
+extern void xpc_create_kthreads(struct xpc_channel *, int, int);
extern void xpc_disconnect_wait(int);
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