2 files changed, 28 insertions, 0 deletions

diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index d8d1fadb398a..3184f6ff4e74 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -570,6 +570,10 @@ u32 hv_get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *ring_info);
 void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
                             struct hv_ring_buffer_debug_info *debug_info);
 
+void hv_begin_read(struct hv_ring_buffer_info *rbi);
+
+u32 hv_end_read(struct hv_ring_buffer_info *rbi);
+
 /*
  * Maximum channels is determined by the size of the interrupt page
  * which is PAGE_SIZE. 1/2 of PAGE_SIZE is for send endpoint interrupt
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 7233c88f01b8..001079287709 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -29,6 +29,30 @@
 
 #include "hyperv_vmbus.h"
 
+void hv_begin_read(struct hv_ring_buffer_info *rbi)
+{
+        rbi->ring_buffer->interrupt_mask = 1;
+        smp_mb();
+}
+
+u32 hv_end_read(struct hv_ring_buffer_info *rbi)
+{
+        u32 read;
+        u32 write;
+
+        rbi->ring_buffer->interrupt_mask = 0;
+        smp_mb();
+
+        /*
+         * Now check to see if the ring buffer is still empty.
+         * If it is not, we raced and we need to process new
+         * incoming messages.
+         */
+        hv_get_ringbuffer_availbytes(rbi, &read, &write);
+
+        return read;
+}
+
 
 /*
  * hv_get_next_write_location()