3 files changed, 79 insertions, 48 deletions

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 64d0c85d5161..1f1a55e07733 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -164,26 +164,25 @@ hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
 }
 
 /* Get various debug metrics for the specified ring buffer. */
-void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
-                                 struct hv_ring_buffer_debug_info *debug_info)
+int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+                                struct hv_ring_buffer_debug_info *debug_info)
 {
         u32 bytes_avail_towrite;
         u32 bytes_avail_toread;
 
-        if (ring_info->ring_buffer) {
-                hv_get_ringbuffer_availbytes(ring_info,
-                                        &bytes_avail_toread,
-                                        &bytes_avail_towrite);
-
-                debug_info->bytes_avail_toread = bytes_avail_toread;
-                debug_info->bytes_avail_towrite = bytes_avail_towrite;
-                debug_info->current_read_index =
-                        ring_info->ring_buffer->read_index;
-                debug_info->current_write_index =
-                        ring_info->ring_buffer->write_index;
-                debug_info->current_interrupt_mask =
-                        ring_info->ring_buffer->interrupt_mask;
-        }
+        if (!ring_info->ring_buffer)
+                return -EINVAL;
+
+        hv_get_ringbuffer_availbytes(ring_info,
+                                     &bytes_avail_toread,
+                                     &bytes_avail_towrite);
+        debug_info->bytes_avail_toread = bytes_avail_toread;
+        debug_info->bytes_avail_towrite = bytes_avail_towrite;
+        debug_info->current_read_index = ring_info->ring_buffer->read_index;
+        debug_info->current_write_index = ring_info->ring_buffer->write_index;
+        debug_info->current_interrupt_mask
+                = ring_info->ring_buffer->interrupt_mask;
+        return 0;
 }
 EXPORT_SYMBOL_GPL(hv_ringbuffer_get_debuginfo);
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index d0ff65675292..403fee01572c 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -313,12 +313,16 @@ static ssize_t out_intr_mask_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info outbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+                                          &outbound);
+        if (ret < 0)
+                return ret;
+
         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 }
 static DEVICE_ATTR_RO(out_intr_mask);
@@ -328,12 +332,15 @@ static ssize_t out_read_index_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info outbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+                                          &outbound);
+        if (ret < 0)
+                return ret;
         return sprintf(buf, "%d\n", outbound.current_read_index);
 }
 static DEVICE_ATTR_RO(out_read_index);
@@ -344,12 +351,15 @@ static ssize_t out_write_index_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info outbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+                                          &outbound);
+        if (ret < 0)
+                return ret;
         return sprintf(buf, "%d\n", outbound.current_write_index);
 }
 static DEVICE_ATTR_RO(out_write_index);
@@ -360,12 +370,15 @@ static ssize_t out_read_bytes_avail_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info outbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+                                          &outbound);
+        if (ret < 0)
+                return ret;
         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 }
 static DEVICE_ATTR_RO(out_read_bytes_avail);
@@ -376,12 +389,15 @@ static ssize_t out_write_bytes_avail_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info outbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+                                          &outbound);
+        if (ret < 0)
+                return ret;
         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 }
 static DEVICE_ATTR_RO(out_write_bytes_avail);
@@ -391,12 +407,15 @@ static ssize_t in_intr_mask_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info inbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+        if (ret < 0)
+                return ret;
+
         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 }
 static DEVICE_ATTR_RO(in_intr_mask);
@@ -406,12 +425,15 @@ static ssize_t in_read_index_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info inbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+        if (ret < 0)
+                return ret;
+
         return sprintf(buf, "%d\n", inbound.current_read_index);
 }
 static DEVICE_ATTR_RO(in_read_index);
@@ -421,12 +443,15 @@ static ssize_t in_write_index_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info inbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+        if (ret < 0)
+                return ret;
+
         return sprintf(buf, "%d\n", inbound.current_write_index);
 }
 static DEVICE_ATTR_RO(in_write_index);
@@ -437,12 +462,15 @@ static ssize_t in_read_bytes_avail_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info inbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+        if (ret < 0)
+                return ret;
+
         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 }
 static DEVICE_ATTR_RO(in_read_bytes_avail);
@@ -453,12 +481,15 @@ static ssize_t in_write_bytes_avail_show(struct device *dev,
 {
         struct hv_device *hv_dev = device_to_hv_device(dev);
         struct hv_ring_buffer_debug_info inbound;
+        int ret;
 
         if (!hv_dev->channel)
                 return -ENODEV;
-        if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
-                return -EINVAL;
-        hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+
+        ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+        if (ret < 0)
+                return ret;
+
         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 }
 static DEVICE_ATTR_RO(in_write_bytes_avail);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f0885cc01db6..dcb6977afce9 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1159,8 +1159,9 @@ struct hv_ring_buffer_debug_info {
         u32 bytes_avail_towrite;
 };
 
-void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
-                            struct hv_ring_buffer_debug_info *debug_info);
+
+int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+                                struct hv_ring_buffer_debug_info *debug_info);
 
 /* Vmbus interface */
 #define vmbus_driver_register(driver)   \