From: Robin Holt 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. I also modified all the *mb() operations to be prefixed with smp_ as they all are really only needed when running with multiple cpus. Signed-off-by: Robin Holt Signed-off-by: Dean Nelson Cc: --- drivers/misc/sgi-xp/xpc_sn2.c | 9 +++++---- drivers/misc/sgi-xp/xpc_uv.c | 2 +- 2 files changed, 6 insertions(+), 5 deletions(-) Index: xpc-fixes-20090115/drivers/misc/sgi-xp/xpc_sn2.c =================================================================== --- xpc-fixes-20090115.orig/drivers/misc/sgi-xp/xpc_sn2.c 2009-01-21 09:32:18.601506191 -0600 +++ xpc-fixes-20090115/drivers/misc/sgi-xp/xpc_sn2.c 2009-01-21 09:44:14.930207605 -0600 @@ -1836,6 +1836,7 @@ xpc_process_msg_chctl_flags_sn2(struct x */ xpc_clear_remote_msgqueue_flags_sn2(ch); + smp_wmb(); /* ensure flags have been cleared before bte_copy */ ch_sn2->w_remote_GP.put = ch_sn2->remote_GP.put; dev_dbg(xpc_chan, "w_remote_GP.put changed to %ld, partid=%d, " @@ -1934,7 +1935,7 @@ xpc_get_deliverable_payload_sn2(struct x break; get = ch_sn2->w_local_GP.get; - rmb(); /* guarantee that .get loads before .put */ + smp_rmb(); /* guarantee that .get loads before .put */ if (get == ch_sn2->w_remote_GP.put) break; @@ -2053,7 +2054,7 @@ xpc_allocate_msg_sn2(struct xpc_channel while (1) { put = ch_sn2->w_local_GP.put; - rmb(); /* guarantee that .put loads before .get */ + smp_rmb(); /* guarantee that .put loads before .get */ if (put - ch_sn2->w_remote_GP.get < ch->local_nentries) { /* There are available message entries. We need to try @@ -2186,7 +2187,7 @@ xpc_send_payload_sn2(struct xpc_channel * The preceding store of msg->flags must occur before the following * load of local_GP->put. */ - mb(); + smp_mb(); /* see if the message is next in line to be sent, if so send it */ @@ -2287,7 +2288,7 @@ xpc_received_payload_sn2(struct xpc_chan * The preceding store of msg->flags must occur before the following * load of local_GP->get. */ - mb(); + smp_mb(); /* * See if this message is next in line to be acknowledged as having Index: xpc-fixes-20090115/drivers/misc/sgi-xp/xpc_uv.c =================================================================== --- xpc-fixes-20090115.orig/drivers/misc/sgi-xp/xpc_uv.c 2009-01-15 09:55:59.000000000 -0600 +++ xpc-fixes-20090115/drivers/misc/sgi-xp/xpc_uv.c 2009-01-21 09:44:34.296607895 -0600 @@ -1423,7 +1423,7 @@ xpc_send_payload_uv(struct xpc_channel * 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) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/