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Diffstat (limited to 'arch/ia64/sn/kernel/xpc_main.c')
-rw-r--r--arch/ia64/sn/kernel/xpc_main.c64
1 files changed, 43 insertions, 21 deletions
diff --git a/arch/ia64/sn/kernel/xpc_main.c b/arch/ia64/sn/kernel/xpc_main.c
index fa96dfc0e1a..7a387d23736 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,