sgi-xpc: ensure flags are updated before bte_copy
The clearing of the msg->flags needs a barrier between it and the notify
of the channel threads that the messages are cleaned and ready for use.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
index 91a55b1..f17f7d4 100644
--- a/drivers/misc/sgi-xp/xpc_uv.c
+++ b/drivers/misc/sgi-xp/xpc_uv.c
@@ -1423,7 +1423,7 @@
atomic_inc(&ch->n_to_notify);
msg_slot->key = key;
- wmb(); /* a non-NULL func must hit memory after the key */
+ smp_wmb(); /* a non-NULL func must hit memory after the key */
msg_slot->func = func;
if (ch->flags & XPC_C_DISCONNECTING) {