Commit 69b3bb65 authored by Robin Holt's avatar Robin Holt Committed by Linus Torvalds
Browse files

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: default avatarRobin Holt <holt@sgi.com>
Signed-off-by: default avatarDean Nelson <dcn@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent de33c8db

drivers/misc/sgi-xp/xpc_sn2.c

+5 −4
Original line number Diff line number Diff line
@@ -1836,6 +1836,7 @@ xpc_process_msg_chctl_flags_sn2(struct xpc_partition *part, int ch_number) 
		 */

		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 xpc_channel *ch) 
			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 *ch, u32 flags, 
	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 *ch, u32 flags, void *payload, 
	 * 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_channel *ch, void *payload) 
	 * 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

drivers/misc/sgi-xp/xpc_uv.c

+1 −1
Original line number Diff line number Diff line
@@ -1423,7 +1423,7 @@ xpc_send_payload_uv(struct xpc_channel *ch, u32 flags, void *payload, 
		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) {

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