1 files changed, 133 insertions, 341 deletions

diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
index c1943f2b83fb..8524ce128738 100644
--- a/drivers/staging/greybus/loopback.c
+++ b/drivers/staging/greybus/loopback.c
@@ -36,29 +36,11 @@ struct gb_loopback_stats {
 
 struct gb_loopback_device {
 	struct dentry *root;
-	struct dentry *file;
 	u32 count;
+	size_t size_max;
 
-	struct kfifo kfifo;
 	struct mutex mutex;
 	struct list_head list;
-	wait_queue_head_t wq;
-
-	int type;
-	u32 mask;
-	u32 size;
-	u32 iteration_max;
-	u32 iteration_count;
-	size_t size_max;
-	int ms_wait;
-	u32 error;
-
-	/* Overall stats */
-	struct gb_loopback_stats latency;
-	struct gb_loopback_stats throughput;
-	struct gb_loopback_stats requests_per_second;
-	struct gb_loopback_stats apbridge_unipro_latency;
-	struct gb_loopback_stats gpbridge_firmware_latency;
 };
 
 static struct gb_loopback_device gb_dev;
@@ -72,6 +54,7 @@ struct gb_loopback {
 	struct mutex mutex;
 	struct task_struct *task;
 	struct list_head entry;
+	wait_queue_head_t wq;
 
 	/* Per connection stats */
 	struct gb_loopback_stats latency;
@@ -80,10 +63,15 @@ struct gb_loopback {
 	struct gb_loopback_stats apbridge_unipro_latency;
 	struct gb_loopback_stats gpbridge_firmware_latency;
 
-	u32 lbid;
+	int type;
+	u32 mask;
+	u32 size;
+	u32 iteration_max;
 	u32 iteration_count;
-	u64 elapsed_nsecs;
+	int ms_wait;
 	u32 error;
+	u32 lbid;
+	u64 elapsed_nsecs;
 	u32 apbridge_latency_ts;
 	u32 gpbridge_latency_ts;
 };
@@ -99,42 +87,34 @@ module_param(kfifo_depth, uint, 0444);
 #define GB_LOOPBACK_MS_WAIT_MAX				1000
 
 /* interface sysfs attributes */
-#define gb_loopback_ro_attr(field, pfx, conn)				\
-static ssize_t field##_##pfx##_show(struct device *dev,			\
+#define gb_loopback_ro_attr(field)				\
+static ssize_t field##_show(struct device *dev,			\
 			    struct device_attribute *attr,		\
 			    char *buf)					\
 {									\
 	struct gb_bundle *bundle;					\
 	struct gb_loopback *gb;						\
-	if (conn) {							\
-		bundle = to_gb_bundle(dev);				\
-		gb = bundle->private;					\
-		return sprintf(buf, "%u\n", gb->field);			\
-	} else {							\
-		return sprintf(buf, "%u\n", gb_dev.field);		\
-	}								\
+	bundle = to_gb_bundle(dev);				\
+	gb = bundle->private;					\
+	return sprintf(buf, "%u\n", gb->field);			\
 }									\
-static DEVICE_ATTR_RO(field##_##pfx)
+static DEVICE_ATTR_RO(field)
 
-#define gb_loopback_ro_stats_attr(name, field, type, pfx, conn)		\
-static ssize_t name##_##field##_##pfx##_show(struct device *dev,	\
+#define gb_loopback_ro_stats_attr(name, field, type)		\
+static ssize_t name##_##field##_show(struct device *dev,	\
 			    struct device_attribute *attr,		\
 			    char *buf)					\
 {									\
 	struct gb_bundle *bundle;					\
 	struct gb_loopback *gb;						\
-	if (conn) {							\
-		bundle = to_gb_bundle(dev);				\
-		gb = bundle->private;					\
-		return sprintf(buf, "%"#type"\n", gb->name.field);	\
-	} else {							\
-		return sprintf(buf, "%"#type"\n", gb_dev.name.field);	\
-	}								\
+	bundle = to_gb_bundle(dev);				\
+	gb = bundle->private;					\
+	return sprintf(buf, "%"#type"\n", gb->name.field);	\
 }									\
-static DEVICE_ATTR_RO(name##_##field##_##pfx)
+static DEVICE_ATTR_RO(name##_##field)
 
-#define gb_loopback_ro_avg_attr(name, pfx, conn)			\
-static ssize_t name##_avg_##pfx##_show(struct device *dev,		\
+#define gb_loopback_ro_avg_attr(name)			\
+static ssize_t name##_avg_show(struct device *dev,		\
 			    struct device_attribute *attr,		\
 			    char *buf)					\
 {									\
@@ -143,24 +123,20 @@ static ssize_t name##_avg_##pfx##_show(struct device *dev,		\
 	struct gb_loopback *gb;						\
 	u64 avg;							\
 	u32 count, rem;							\
-	if (conn) {							\
-		bundle = to_gb_bundle(dev);				\
-		gb = bundle->private;					\
-		stats = &gb->name;					\
-	} else {							\
-		stats = &gb_dev.name;					\
-	}								\
+	bundle = to_gb_bundle(dev);				\
+	gb = bundle->private;					\
+	stats = &gb->name;					\
 	count = stats->count ? stats->count : 1;			\
 	avg = stats->sum + count / 2;	/* round closest */		\
 	rem = do_div(avg, count);					\
 	return sprintf(buf, "%llu.%06u\n", avg, 1000000 * rem / count);	\
 }									\
-static DEVICE_ATTR_RO(name##_avg_##pfx)
+static DEVICE_ATTR_RO(name##_avg)
 
-#define gb_loopback_stats_attrs(field, pfx, conn)			\
-	gb_loopback_ro_stats_attr(field, min, u, pfx, conn);		\
-	gb_loopback_ro_stats_attr(field, max, u, pfx, conn);		\
-	gb_loopback_ro_avg_attr(field, pfx, conn)
+#define gb_loopback_stats_attrs(field)				\
+	gb_loopback_ro_stats_attr(field, min, u);		\
+	gb_loopback_ro_stats_attr(field, max, u);		\
+	gb_loopback_ro_avg_attr(field)
 
 #define gb_loopback_attr(field, type)					\
 static ssize_t field##_show(struct device *dev,				\
@@ -178,13 +154,14 @@ static ssize_t field##_store(struct device *dev,			\
 {									\
 	int ret;							\
 	struct gb_bundle *bundle = to_gb_bundle(dev);			\
-	mutex_lock(&gb_dev.mutex);					\
+	struct gb_loopback *gb = bundle->private;			\
+	mutex_lock(&gb->mutex);						\
 	ret = sscanf(buf, "%"#type, &gb->field);			\
 	if (ret != 1)							\
 		len = -EINVAL;						\
 	else								\
-		gb_loopback_check_attr(&gb_dev, bundle);		\
-	mutex_unlock(&gb_dev.mutex);					\
+		gb_loopback_check_attr(gb, bundle);			\
+	mutex_unlock(&gb->mutex);					\
 	return len;							\
 }									\
 static DEVICE_ATTR_RW(field)
@@ -194,7 +171,9 @@ static ssize_t field##_show(struct device *dev,		\
 			    struct device_attribute *attr,		\
 			    char *buf)					\
 {									\
-	return sprintf(buf, "%u\n", gb_dev.field);			\
+	struct gb_bundle *bundle = to_gb_bundle(dev);			\
+	struct gb_loopback *gb = bundle->private;			\
+	return sprintf(buf, "%u\n", gb->field);				\
 }									\
 static DEVICE_ATTR_RO(field)
 
@@ -203,7 +182,9 @@ static ssize_t field##_show(struct device *dev,				\
 			    struct device_attribute *attr,		\
 			    char *buf)					\
 {									\
-	return sprintf(buf, "%"#type"\n", gb_dev.field);		\
+	struct gb_bundle *bundle = to_gb_bundle(dev);			\
+	struct gb_loopback *gb = bundle->private;			\
+	return sprintf(buf, "%"#type"\n", gb->field);			\
 }									\
 static ssize_t field##_store(struct device *dev,			\
 			    struct device_attribute *attr,		\
@@ -212,76 +193,63 @@ static ssize_t field##_store(struct device *dev,			\
 {									\
 	int ret;							\
 	struct gb_bundle *bundle = to_gb_bundle(dev);			\
-	mutex_lock(&gb_dev.mutex);					\
-	ret = sscanf(buf, "%"#type, &gb_dev.field);			\
+	struct gb_loopback *gb = bundle->private;			\
+	mutex_lock(&gb->mutex);						\
+	ret = sscanf(buf, "%"#type, &gb->field);			\
 	if (ret != 1)							\
 		len = -EINVAL;						\
 	else								\
-		gb_loopback_check_attr(&gb_dev, bundle);		\
-	mutex_unlock(&gb_dev.mutex);					\
+		gb_loopback_check_attr(gb, bundle);		\
+	mutex_unlock(&gb->mutex);					\
 	return len;							\
 }									\
 static DEVICE_ATTR_RW(field)
 
-static void gb_loopback_reset_stats(struct gb_loopback_device *gb_dev);
-static void gb_loopback_check_attr(struct gb_loopback_device *gb_dev,
+static void gb_loopback_reset_stats(struct gb_loopback *gb);
+static void gb_loopback_check_attr(struct gb_loopback *gb,
 				   struct gb_bundle *bundle)
 {
-	struct gb_loopback *gb;
-
-	if (gb_dev->ms_wait > GB_LOOPBACK_MS_WAIT_MAX)
-		gb_dev->ms_wait = GB_LOOPBACK_MS_WAIT_MAX;
-	if (gb_dev->size > gb_dev->size_max)
-		gb_dev->size = gb_dev->size_max;
-	gb_dev->iteration_count = 0;
-	gb_dev->error = 0;
-
-	list_for_each_entry(gb, &gb_dev->list, entry) {
-		mutex_lock(&gb->mutex);
-		gb->iteration_count = 0;
-		gb->error = 0;
-		if (kfifo_depth < gb_dev->iteration_max) {
-			dev_warn(&bundle->dev,
-				 "cannot log bytes %u kfifo_depth %u\n",
-				 gb_dev->iteration_max, kfifo_depth);
-		}
-		kfifo_reset_out(&gb->kfifo_lat);
-		kfifo_reset_out(&gb->kfifo_ts);
-		mutex_unlock(&gb->mutex);
+	if (gb->ms_wait > GB_LOOPBACK_MS_WAIT_MAX)
+		gb->ms_wait = GB_LOOPBACK_MS_WAIT_MAX;
+	if (gb->size > gb_dev.size_max)
+		gb->size = gb_dev.size_max;
+	gb->iteration_count = 0;
+	gb->error = 0;
+
+	if (kfifo_depth < gb->iteration_max) {
+		dev_warn(&bundle->dev,
+			 "cannot log bytes %u kfifo_depth %u\n",
+			 gb->iteration_max, kfifo_depth);
 	}
+	kfifo_reset_out(&gb->kfifo_lat);
+	kfifo_reset_out(&gb->kfifo_ts);
 
-	switch (gb_dev->type) {
+	switch (gb->type) {
 	case GB_LOOPBACK_TYPE_PING:
 	case GB_LOOPBACK_TYPE_TRANSFER:
 	case GB_LOOPBACK_TYPE_SINK:
-		kfifo_reset_out(&gb_dev->kfifo);
-		gb_loopback_reset_stats(gb_dev);
-		wake_up(&gb_dev->wq);
+		gb_loopback_reset_stats(gb);
+		wake_up(&gb->wq);
 		break;
 	default:
-		gb_dev->type = 0;
+		gb->type = 0;
 		break;
 	}
 }
 
 /* Time to send and receive one message */
-gb_loopback_stats_attrs(latency, dev, false);
-gb_loopback_stats_attrs(latency, con, true);
+gb_loopback_stats_attrs(latency);
 /* Number of requests sent per second on this cport */
-gb_loopback_stats_attrs(requests_per_second, dev, false);
-gb_loopback_stats_attrs(requests_per_second, con, true);
+gb_loopback_stats_attrs(requests_per_second);
 /* Quantity of data sent and received on this cport */
-gb_loopback_stats_attrs(throughput, dev, false);
-gb_loopback_stats_attrs(throughput, con, true);
+gb_loopback_stats_attrs(throughput);
 /* Latency across the UniPro link from APBridge's perspective */
-gb_loopback_stats_attrs(apbridge_unipro_latency, dev, false);
-gb_loopback_stats_attrs(apbridge_unipro_latency, con, true);
+gb_loopback_stats_attrs(apbridge_unipro_latency);
 /* Firmware induced overhead in the GPBridge */
-gb_loopback_stats_attrs(gpbridge_firmware_latency, dev, false);
-gb_loopback_stats_attrs(gpbridge_firmware_latency, con, true);
+gb_loopback_stats_attrs(gpbridge_firmware_latency);
+
 /* Number of errors encountered during loop */
-gb_loopback_ro_attr(error, dev, false);
-gb_loopback_ro_attr(error, con, true);
+gb_loopback_ro_attr(error);
 
 /*
  * Type of loopback message to send based on protocol type definitions
@@ -303,53 +271,32 @@ gb_dev_loopback_ro_attr(iteration_count, false);
 /* A bit-mask of destination connecitons to include in the test run */
 gb_dev_loopback_rw_attr(mask, u);
 
-static struct attribute *loopback_dev_attrs[] = {
-	&dev_attr_latency_min_dev.attr,
-	&dev_attr_latency_max_dev.attr,
-	&dev_attr_latency_avg_dev.attr,
-	&dev_attr_requests_per_second_min_dev.attr,
-	&dev_attr_requests_per_second_max_dev.attr,
-	&dev_attr_requests_per_second_avg_dev.attr,
-	&dev_attr_throughput_min_dev.attr,
-	&dev_attr_throughput_max_dev.attr,
-	&dev_attr_throughput_avg_dev.attr,
-	&dev_attr_apbridge_unipro_latency_min_dev.attr,
-	&dev_attr_apbridge_unipro_latency_max_dev.attr,
-	&dev_attr_apbridge_unipro_latency_avg_dev.attr,
-	&dev_attr_gpbridge_firmware_latency_min_dev.attr,
-	&dev_attr_gpbridge_firmware_latency_max_dev.attr,
-	&dev_attr_gpbridge_firmware_latency_avg_dev.attr,
+static struct attribute *loopback_attrs[] = {
+	&dev_attr_latency_min.attr,
+	&dev_attr_latency_max.attr,
+	&dev_attr_latency_avg.attr,
+	&dev_attr_requests_per_second_min.attr,
+	&dev_attr_requests_per_second_max.attr,
+	&dev_attr_requests_per_second_avg.attr,
+	&dev_attr_throughput_min.attr,
+	&dev_attr_throughput_max.attr,
+	&dev_attr_throughput_avg.attr,
+	&dev_attr_apbridge_unipro_latency_min.attr,
+	&dev_attr_apbridge_unipro_latency_max.attr,
+	&dev_attr_apbridge_unipro_latency_avg.attr,
+	&dev_attr_gpbridge_firmware_latency_min.attr,
+	&dev_attr_gpbridge_firmware_latency_max.attr,
+	&dev_attr_gpbridge_firmware_latency_avg.attr,
 	&dev_attr_type.attr,
 	&dev_attr_size.attr,
 	&dev_attr_ms_wait.attr,
 	&dev_attr_iteration_count.attr,
 	&dev_attr_iteration_max.attr,
 	&dev_attr_mask.attr,
-	&dev_attr_error_dev.attr,
+	&dev_attr_error.attr,
 	NULL,
 };
-ATTRIBUTE_GROUPS(loopback_dev);
-
-static struct attribute *loopback_con_attrs[] = {
-	&dev_attr_latency_min_con.attr,
-	&dev_attr_latency_max_con.attr,
-	&dev_attr_latency_avg_con.attr,
-	&dev_attr_requests_per_second_min_con.attr,
-	&dev_attr_requests_per_second_max_con.attr,
-	&dev_attr_requests_per_second_avg_con.attr,
-	&dev_attr_throughput_min_con.attr,
-	&dev_attr_throughput_max_con.attr,
-	&dev_attr_throughput_avg_con.attr,
-	&dev_attr_apbridge_unipro_latency_min_con.attr,
-	&dev_attr_apbridge_unipro_latency_max_con.attr,
-	&dev_attr_apbridge_unipro_latency_avg_con.attr,
-	&dev_attr_gpbridge_firmware_latency_min_con.attr,
-	&dev_attr_gpbridge_firmware_latency_max_con.attr,
-	&dev_attr_gpbridge_firmware_latency_avg_con.attr,
-	&dev_attr_error_con.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(loopback_con);
+ATTRIBUTE_GROUPS(loopback);
 
 static u32 gb_loopback_nsec_to_usec_latency(u64 elapsed_nsecs)
 {
@@ -385,11 +332,6 @@ static void gb_loopback_push_latency_ts(struct gb_loopback *gb,
 	kfifo_in(&gb->kfifo_ts, (unsigned char *)te, sizeof(*te));
 }
 
-static int gb_loopback_active(struct gb_loopback *gb)
-{
-	return (gb_dev.mask == 0 || (gb_dev.mask & gb->lbid));
-}
-
 static int gb_loopback_operation_sync(struct gb_loopback *gb, int type,
 				      void *request, int request_size,
 				      void *response, int response_size)
@@ -550,37 +492,32 @@ static int gb_loopback_request_recv(u8 type, struct gb_operation *operation)
 	}
 }
 
-static void gb_loopback_reset_stats(struct gb_loopback_device *gb_dev)
+static void gb_loopback_reset_stats(struct gb_loopback *gb)
 {
 	struct gb_loopback_stats reset = {
 		.min = U32_MAX,
 	};
-	struct gb_loopback *gb;
 
 	/* Reset per-connection stats */
-	list_for_each_entry(gb, &gb_dev->list, entry) {
-		mutex_lock(&gb->mutex);
-		memcpy(&gb->latency, &reset,
-		       sizeof(struct gb_loopback_stats));
-		memcpy(&gb->throughput, &reset,
-		       sizeof(struct gb_loopback_stats));
-		memcpy(&gb->requests_per_second, &reset,
-		       sizeof(struct gb_loopback_stats));
-		memcpy(&gb->apbridge_unipro_latency, &reset,
-		       sizeof(struct gb_loopback_stats));
-		memcpy(&gb->gpbridge_firmware_latency, &reset,
-		       sizeof(struct gb_loopback_stats));
-		mutex_unlock(&gb->mutex);
-	}
+	memcpy(&gb->latency, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->throughput, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->requests_per_second, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->apbridge_unipro_latency, &reset,
+	       sizeof(struct gb_loopback_stats));
+	memcpy(&gb->gpbridge_firmware_latency, &reset,
+	       sizeof(struct gb_loopback_stats));
 
 	/* Reset aggregate stats */
-	memcpy(&gb_dev->latency, &reset, sizeof(struct gb_loopback_stats));
-	memcpy(&gb_dev->throughput, &reset, sizeof(struct gb_loopback_stats));
-	memcpy(&gb_dev->requests_per_second, &reset,
+	memcpy(&gb->latency, &reset, sizeof(struct gb_loopback_stats));
+	memcpy(&gb->throughput, &reset, sizeof(struct gb_loopback_stats));
+	memcpy(&gb->requests_per_second, &reset,
 	       sizeof(struct gb_loopback_stats));
-	memcpy(&gb_dev->apbridge_unipro_latency, &reset,
+	memcpy(&gb->apbridge_unipro_latency, &reset,
 	       sizeof(struct gb_loopback_stats));
-	memcpy(&gb_dev->gpbridge_firmware_latency, &reset,
+	memcpy(&gb->gpbridge_firmware_latency, &reset,
 	       sizeof(struct gb_loopback_stats));
 }
 
@@ -599,7 +536,6 @@ static void gb_loopback_requests_update(struct gb_loopback *gb, u32 latency)
 	u32 req = USEC_PER_SEC;
 
 	do_div(req, latency);
-	gb_loopback_update_stats(&gb_dev.requests_per_second, req);
 	gb_loopback_update_stats(&gb->requests_per_second, req);
 }
 
@@ -608,17 +544,17 @@ static void gb_loopback_throughput_update(struct gb_loopback *gb, u32 latency)
 	u32 throughput;
 	u32 aggregate_size = sizeof(struct gb_operation_msg_hdr) * 2;
 
-	switch (gb_dev.type) {
+	switch (gb->type) {
 	case GB_LOOPBACK_TYPE_PING:
 		break;
 	case GB_LOOPBACK_TYPE_SINK:
 		aggregate_size += sizeof(struct gb_loopback_transfer_request) +
-				  gb_dev.size;
+				  gb->size;
 		break;
 	case GB_LOOPBACK_TYPE_TRANSFER:
 		aggregate_size += sizeof(struct gb_loopback_transfer_request) +
 				  sizeof(struct gb_loopback_transfer_response) +
-				  gb_dev.size * 2;
+				  gb->size * 2;
 		break;
 	default:
 		return;
@@ -628,65 +564,9 @@ static void gb_loopback_throughput_update(struct gb_loopback *gb, u32 latency)
 	throughput = USEC_PER_SEC;
 	do_div(throughput, latency);
 	throughput *= aggregate_size;
-	gb_loopback_update_stats(&gb_dev.throughput, throughput);
 	gb_loopback_update_stats(&gb->throughput, throughput);
 }
 
-static int gb_loopback_calculate_aggregate_stats(void)
-{
-	struct gb_loopback *gb;
-	struct timeval ts;
-	struct timeval te;
-	u64 t1, t2;
-	u64 ts_min;
-	u64 te_max;
-	u64 elapsed_nsecs;
-	u32 lat;
-	int i, latched;
-	int rollover = 0;
-
-	for (i = 0; i < gb_dev.iteration_max; i++) {
-		latched = 0;
-		ts_min = 0;
-		te_max = 0;
-		list_for_each_entry(gb, &gb_dev.list, entry) {
-			if (!gb_loopback_active(gb))
-				continue;
-			if (kfifo_out(&gb->kfifo_ts, &ts, sizeof(ts)) < sizeof(ts))
-				goto error;
-			if (kfifo_out(&gb->kfifo_ts, &te, sizeof(te)) < sizeof(te))
-				goto error;
-			t1 = timeval_to_ns(&ts);
-			t2 = timeval_to_ns(&te);
-
-			/* minimum timestamp is always what we want */
-			if (latched == 0 || t1 < ts_min)
-				ts_min = t1;
-
-			/* maximum timestamp needs to handle rollover */
-			if (t2 > t1) {
-				if (latched == 0 || t2 > te_max)
-					te_max = t2;
-			} else {
-				if (latched == 0 || rollover == 0)
-					te_max = t2;
-				if (rollover == 1 && t2 > te_max)
-					te_max = t2;
-				rollover = 1;
-			}
-			latched = 1;
-		}
-		/* Calculate the aggregate timestamp */
-		elapsed_nsecs = __gb_loopback_calc_latency(ts_min, te_max);
-		lat = gb_loopback_nsec_to_usec_latency(elapsed_nsecs);
-		kfifo_in(&gb_dev.kfifo, (unsigned char *)&lat, sizeof(lat));
-	}
-	return 0;
-error:
-	kfifo_reset_out(&gb_dev.kfifo);
-	return -ENOMEM;
-}
-
 static void gb_loopback_calculate_stats(struct gb_loopback *gb)
 {
 	u32 lat;
@@ -695,7 +575,6 @@ static void gb_loopback_calculate_stats(struct gb_loopback *gb)
 	lat = gb_loopback_nsec_to_usec_latency(gb->elapsed_nsecs);
 
 	/* Log latency stastic */
-	gb_loopback_update_stats(&gb_dev.latency, lat);
 	gb_loopback_update_stats(&gb->latency, lat);
 
 	/* Raw latency log on a per thread basis */
@@ -706,12 +585,8 @@ static void gb_loopback_calculate_stats(struct gb_loopback *gb)
 	gb_loopback_requests_update(gb, lat);
 
 	/* Log the firmware supplied latency values */
-	gb_loopback_update_stats(&gb_dev.apbridge_unipro_latency,
-				 gb->apbridge_latency_ts);
 	gb_loopback_update_stats(&gb->apbridge_unipro_latency,
 				 gb->apbridge_latency_ts);
-	gb_loopback_update_stats(&gb_dev.gpbridge_firmware_latency,
-				 gb->gpbridge_latency_ts);
 	gb_loopback_update_stats(&gb->gpbridge_firmware_latency,
 				 gb->gpbridge_latency_ts);
 }
@@ -722,56 +597,29 @@ static int gb_loopback_fn(void *data)
 	int ms_wait = 0;
 	int type;
 	u32 size;
-	u32 low_count;
 	struct gb_loopback *gb = data;
-	struct gb_loopback *gb_list;
 
 	while (1) {
-		if (!gb_dev.type)
-			wait_event_interruptible(gb_dev.wq, gb_dev.type ||
+		if (!gb->type)
+			wait_event_interruptible(gb->wq, gb->type ||
 						 kthread_should_stop());
 		if (kthread_should_stop())
 			break;
 
-		mutex_lock(&gb_dev.mutex);
-		if (!gb_loopback_active(gb)) {
-			ms_wait = 100;
-			goto unlock_continue;
-		}
-		if (gb_dev.iteration_max) {
-			/* Determine overall lowest count */
-			low_count = gb->iteration_count;
-			list_for_each_entry(gb_list, &gb_dev.list, entry) {
-				if (!gb_loopback_active(gb_list))
-					continue;
-				if (gb_list->iteration_count < low_count)
-					low_count = gb_list->iteration_count;
-			}
-			/* All threads achieved at least low_count iterations */
-			if (gb_dev.iteration_count < low_count) {
-				gb_dev.iteration_count = low_count;
-				sysfs_notify(&gb->connection->bundle->dev.kobj,
-					     NULL, "iteration_count");
-			}
-			/* Optionally terminate */
-			if (gb_dev.iteration_count == gb_dev.iteration_max) {
-				gb_loopback_calculate_aggregate_stats();
-				gb_dev.type = 0;
-				goto unlock_continue;
-			}
-		}
-		size = gb_dev.size;
-		ms_wait = gb_dev.ms_wait;
-		type = gb_dev.type;
-		mutex_unlock(&gb_dev.mutex);
-
 		mutex_lock(&gb->mutex);
-		if (gb->iteration_count >= gb_dev.iteration_max) {
-			/* If this thread finished before siblings then sleep */
-			ms_wait = 1;
+
+		sysfs_notify(&gb->connection->bundle->dev.kobj,
+			     NULL, "iteration_count");
+
+		/* Optionally terminate */
+		if (gb->iteration_count == gb->iteration_max) {
+			gb->type = 0;
 			mutex_unlock(&gb->mutex);
-			goto sleep;
+			continue;
 		}
+		size = gb->size;
+		ms_wait = gb->ms_wait;
+		type = gb->type;
 		mutex_unlock(&gb->mutex);
 
 		/* Else operations to perform */
@@ -782,20 +630,12 @@ static int gb_loopback_fn(void *data)
 		else if (type == GB_LOOPBACK_TYPE_SINK)
 			error = gb_loopback_sink(gb, size);
 
-		mutex_lock(&gb_dev.mutex);
-		mutex_lock(&gb->mutex);
-
-		if (error) {
-			gb_dev.error++;
+		if (error)
 			gb->error++;
-		}
+
 		gb_loopback_calculate_stats(gb);
 		gb->iteration_count++;
 
-		mutex_unlock(&gb->mutex);
-unlock_continue:
-		mutex_unlock(&gb_dev.mutex);
-sleep:
 		if (ms_wait)
 			msleep(ms_wait);
 	}
@@ -846,27 +686,6 @@ static const struct file_operations gb_loopback_debugfs_latency_ops = {
 	.release	= single_release,
 };
 
-static int gb_loopback_dbgfs_dev_latency_show(struct seq_file *s, void *unused)
-{
-	struct gb_loopback_device *gb_dev = s->private;
-
-	return gb_loopback_dbgfs_latency_show_common(s, &gb_dev->kfifo,
-						     &gb_dev->mutex);
-}
-
-static int gb_loopback_dev_latency_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, gb_loopback_dbgfs_dev_latency_show,
-			   inode->i_private);
-}
-
-static const struct file_operations gb_loopback_debugfs_dev_latency_ops = {
-	.open		= gb_loopback_dev_latency_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
 static int gb_loopback_bus_id_compare(void *priv, struct list_head *lha,
 				      struct list_head *lhb)
 {
@@ -912,31 +731,22 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
 	struct gb_loopback *gb;
 	int retval;
 	char name[DEBUGFS_NAMELEN];
-	struct kobject *kobj = &connection->bundle->dev.kobj;
 
 	gb = kzalloc(sizeof(*gb), GFP_KERNEL);
 	if (!gb)
 		return -ENOMEM;
-	gb_loopback_reset_stats(&gb_dev);
 
-	/* If this is the first connection - create a per-bus entry */
+	init_waitqueue_head(&gb->wq);
+	gb_loopback_reset_stats(gb);
+
 	mutex_lock(&gb_dev.mutex);
 	if (!gb_dev.count) {
-		snprintf(name, sizeof(name), "raw_latency_%d",
-				connection->bundle->intf->hd->bus_id);
-		gb_dev.file = debugfs_create_file(name, S_IFREG | S_IRUGO,
-						  gb_dev.root, &gb_dev,
-				  &gb_loopback_debugfs_dev_latency_ops);
-		retval = sysfs_create_groups(kobj, loopback_dev_groups);
-		if (retval)
-			goto out_sysfs;
-
 		/* Calculate maximum payload */
 		gb_dev.size_max = gb_operation_get_payload_size_max(connection);
 		if (gb_dev.size_max <=
 			sizeof(struct gb_loopback_transfer_request)) {
 			retval = -EINVAL;
-			goto out_sysfs_dev;
+			goto out_sysfs;
 		}
 		gb_dev.size_max -= sizeof(struct gb_loopback_transfer_request);
 	}
@@ -949,9 +759,9 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
 	gb->connection = connection;
 	connection->bundle->private = gb;
 	retval = sysfs_create_groups(&connection->bundle->dev.kobj,
-				     loopback_con_groups);
+				     loopback_groups);
 	if (retval)
-		goto out_sysfs_dev;
+		goto out_sysfs;
 
 	/* Allocate kfifo */
 	if (kfifo_alloc(&gb->kfifo_lat, kfifo_depth * sizeof(u32),
@@ -984,15 +794,10 @@ out_kfifo1:
 out_kfifo0:
 	kfifo_free(&gb->kfifo_lat);
 out_sysfs_conn:
-	sysfs_remove_groups(&connection->bundle->dev.kobj, loopback_con_groups);
-out_sysfs_dev:
-	if (!gb_dev.count) {
-		sysfs_remove_groups(kobj, loopback_dev_groups);
-		debugfs_remove(gb_dev.file);
-	}
+	sysfs_remove_groups(&connection->bundle->dev.kobj, loopback_groups);
+out_sysfs:
 	debugfs_remove(gb->file);
 	connection->bundle->private = NULL;
-out_sysfs:
 	mutex_unlock(&gb_dev.mutex);
 	kfree(gb);
 
@@ -1002,7 +807,6 @@ out_sysfs:
 static void gb_loopback_connection_exit(struct gb_connection *connection)
 {
 	struct gb_loopback *gb = connection->bundle->private;
-	struct kobject *kobj = &connection->bundle->dev.kobj;
 
 	if (!IS_ERR_OR_NULL(gb->task))
 		kthread_stop(gb->task);
@@ -1014,12 +818,8 @@ static void gb_loopback_connection_exit(struct gb_connection *connection)
 	kfifo_free(&gb->kfifo_ts);
 	gb_connection_latency_tag_disable(connection);
 	gb_dev.count--;
-	if (!gb_dev.count) {
-		sysfs_remove_groups(kobj, loopback_dev_groups);
-		debugfs_remove(gb_dev.file);
-	}
 	sysfs_remove_groups(&connection->bundle->dev.kobj,
-			    loopback_con_groups);
+			    loopback_groups);
 	debugfs_remove(gb->file);
 	list_del(&gb->entry);
 	mutex_unlock(&gb_dev.mutex);
@@ -1040,21 +840,14 @@ static int loopback_init(void)
 {
 	int retval;
 
-	init_waitqueue_head(&gb_dev.wq);
 	INIT_LIST_HEAD(&gb_dev.list);
 	mutex_init(&gb_dev.mutex);
 	gb_dev.root = debugfs_create_dir("gb_loopback", NULL);
 
-	if (kfifo_alloc(&gb_dev.kfifo, kfifo_depth * sizeof(u32), GFP_KERNEL)) {
-		retval = -ENOMEM;
-		goto error_debugfs;
-	}
-
 	retval = gb_protocol_register(&loopback_protocol);
 	if (!retval)
 		return retval;
 
-error_debugfs:
 	debugfs_remove_recursive(gb_dev.root);
 	return retval;
 }
@@ -1063,7 +856,6 @@ module_init(loopback_init);
 static void __exit loopback_exit(void)
 {
 	debugfs_remove_recursive(gb_dev.root);
-	kfifo_free(&gb_dev.kfifo);
 	gb_protocol_deregister(&loopback_protocol);
 }
 module_exit(loopback_exit);