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Commit ca3df03b authored by Phil Elwell's avatar Phil Elwell Committed by Greg Kroah-Hartman
Browse files

staging: vc04_services: Fix messages appearing twice 



An issue was observed when flushing openmax components
which generate a large number of messages returning
buffers to host.

We occasionally found a duplicate message from 16
messages prior, resulting in a buffer returned twice.

So fix the issue by adding more memory barriers.

Signed-off-by: default avatarPhil Elwell <phil@raspberrypi.org>
Signed-off-by: default avatarStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5069c86a

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

+27 −18
Original line number Diff line number Diff line
@@ -208,10 +208,11 @@ add_completion(VCHIQ_INSTANCE_T instance, VCHIQ_REASON_T reason, 
	void *bulk_userdata)

{

	VCHIQ_COMPLETION_DATA_T *completion;

	int insert;

	DEBUG_INITIALISE(g_state.local)



	while (instance->completion_insert ==

		(instance->completion_remove + MAX_COMPLETIONS)) {

	insert = instance->completion_insert;

	while ((insert - instance->completion_remove) >= MAX_COMPLETIONS) {

		/* Out of space - wait for the client */

		DEBUG_TRACE(SERVICE_CALLBACK_LINE);

		vchiq_log_trace(vchiq_arm_log_level,
@@ -229,9 +230,7 @@ add_completion(VCHIQ_INSTANCE_T instance, VCHIQ_REASON_T reason, 
		DEBUG_TRACE(SERVICE_CALLBACK_LINE);

	}



	completion =

		 &instance->completions[instance->completion_insert &

		 (MAX_COMPLETIONS - 1)];

	completion = &instance->completions[insert & (MAX_COMPLETIONS - 1)];



	completion->header = header;

	completion->reason = reason;
@@ -252,9 +251,10 @@ add_completion(VCHIQ_INSTANCE_T instance, VCHIQ_REASON_T reason, 
	wmb();



	if (reason == VCHIQ_MESSAGE_AVAILABLE)

		user_service->message_available_pos =

			instance->completion_insert;

	instance->completion_insert++;

		user_service->message_available_pos = insert;



	insert++;

	instance->completion_insert = insert;



	up(&instance->insert_event);
@@ -895,24 +895,27 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		}

		DEBUG_TRACE(AWAIT_COMPLETION_LINE);



		/* A read memory barrier is needed to stop prefetch of a stale

		** completion record

		*/

		rmb();



		if (ret == 0) {

			int msgbufcount = args.msgbufcount;

			int remove = instance->completion_remove;



			for (ret = 0; ret < args.count; ret++) {

				VCHIQ_COMPLETION_DATA_T *completion;

				VCHIQ_SERVICE_T *service;

				USER_SERVICE_T *user_service;

				VCHIQ_HEADER_T *header;

				if (instance->completion_remove ==

					instance->completion_insert)



				if (remove == instance->completion_insert)

					break;



				completion = &instance->completions[

					instance->completion_remove &

					(MAX_COMPLETIONS - 1)];

					remove & (MAX_COMPLETIONS - 1)];



				/*

				 * A read memory barrier is needed to stop

				 * prefetch of a stale completion record

				 */

				rmb();



				service = completion->service_userdata;

				user_service = service->base.userdata;
@@ -987,7 +990,13 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
					break;

				}



				instance->completion_remove++;

				/*

				 * Ensure that the above copy has completed

				 * before advancing the remove pointer.

				 */

				mb();

				remove++;

				instance->completion_remove = remove;

			}



			if (msgbufcount != args.msgbufcount) {

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

+19 −5
Original line number Diff line number Diff line
@@ -607,15 +607,17 @@ process_free_queue(VCHIQ_STATE_T *state) 
	BITSET_T service_found[BITSET_SIZE(VCHIQ_MAX_SERVICES)];

	int slot_queue_available;



	/* Use a read memory barrier to ensure that any state that may have

	** been modified by another thread is not masked by stale prefetched

	** values. */

	rmb();



	/* Find slots which have been freed by the other side, and return them

	** to the available queue. */

	slot_queue_available = state->slot_queue_available;



	/*

	 * Use a memory barrier to ensure that any state that may have been

	 * modified by another thread is not masked by stale prefetched

	 * values.

	 */

	mb();



	while (slot_queue_available != local->slot_queue_recycle) {

		unsigned int pos;

		int slot_index = local->slot_queue[slot_queue_available++ &
@@ -623,6 +625,12 @@ process_free_queue(VCHIQ_STATE_T *state) 
		char *data = (char *)SLOT_DATA_FROM_INDEX(state, slot_index);

		int data_found = 0;



		/*

		 * Beware of the address dependency - data is calculated

		 * using an index written by the other side.

		 */

		rmb();



		vchiq_log_trace(vchiq_core_log_level, "%d: pfq %d=%pK %x %x",

			state->id, slot_index, data,

			local->slot_queue_recycle, slot_queue_available);
@@ -721,6 +729,12 @@ process_free_queue(VCHIQ_STATE_T *state) 
				up(&state->data_quota_event);

		}



		/*

		 * Don't allow the slot to be reused until we are no

		 * longer interested in it.

		 */

		mb();



		state->slot_queue_available = slot_queue_available;

		up(&state->slot_available_event);

	}