Commit f6c99d86 authored by Phil Elwell's avatar Phil Elwell Committed by Greg Kroah-Hartman
Browse files

staging: vchiq_arm: Add missing memory barrier comments 

One of points on the TODO list was to comment the memory barriers.
This patch addresses the missing ones in order to help reviewers.

Link: https://github.com/raspberrypi/linux/pull/5066


Signed-off-by: default avatarPhil Elwell <phil@raspberrypi.com>
Signed-off-by: default avatarStefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/20220624163902.6913-1-stefan.wahren@i2se.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent acde2522

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c

+4 −0
Original line number Diff line number Diff line
@@ -602,6 +602,10 @@ static struct vchiq_arm_state *vchiq_platform_get_arm_state(struct vchiq_state * 
void

remote_event_signal(struct remote_event *event)

{

	/*

	 * Ensure that all writes to shared data structures have completed

	 * before signalling the peer.

	 */

	wmb();



	event->fired = 1;

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c

+9 −0
Original line number Diff line number Diff line
@@ -528,6 +528,7 @@ remote_event_wait(wait_queue_head_t *wq, struct remote_event *event) 
			return 0;

		}

		event->armed = 0;

		/* Ensure that the peer sees that we are not waiting (armed == 0). */

		wmb();

	}
@@ -650,6 +651,7 @@ request_poll(struct vchiq_state *state, struct vchiq_service *service, 


skip_service:

	state->poll_needed = 1;

	/* Ensure the slot handler thread sees the poll_needed flag. */

	wmb();



	/* ... and ensure the slot handler runs. */
@@ -1156,6 +1158,7 @@ queue_message_sync(struct vchiq_state *state, struct vchiq_service *service, 


	remote_event_wait(&state->sync_release_event, &local->sync_release);



	/* Ensure that reads don't overtake the remote_event_wait. */

	rmb();



	header = (struct vchiq_header *)SLOT_DATA_FROM_INDEX(state,
@@ -1959,6 +1962,7 @@ slot_handler_func(void *v) 
		DEBUG_TRACE(SLOT_HANDLER_LINE);

		remote_event_wait(&state->trigger_event, &local->trigger);



		/* Ensure that reads don't overtake the remote_event_wait. */

		rmb();



		DEBUG_TRACE(SLOT_HANDLER_LINE);
@@ -2021,6 +2025,7 @@ sync_func(void *v) 


		remote_event_wait(&state->sync_trigger_event, &local->sync_trigger);



		/* Ensure that reads don't overtake the remote_event_wait. */

		rmb();



		msgid = header->msgid;
@@ -3081,6 +3086,10 @@ enum vchiq_status vchiq_bulk_transfer(struct vchiq_instance *instance, unsigned 
	if (vchiq_prepare_bulk_data(instance, bulk, offset, uoffset, size, dir))

		goto unlock_error_exit;



	/*

	 * Ensure that the bulk data record is visible to the peer

	 * before proceeding.

	 */

	wmb();



	vchiq_log_info(vchiq_core_log_level, "%d: bt (%d->%d) %cx %x@%pad %pK",