1 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 11b5612dc066..3a3012f57be4 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -35,6 +35,7 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 #include <linux/interrupt.h>
+#include <linux/reciprocal_div.h>
 
 #define MAX_PAGE_BUFFER_COUNT                           32
 #define MAX_MULTIPAGE_BUFFER_COUNT                      32 /* 128K */
@@ -120,6 +121,7 @@ struct hv_ring_buffer {
 struct hv_ring_buffer_info {
         struct hv_ring_buffer *ring_buffer;
         u32 ring_size;                  /* Include the shared header */
+        struct reciprocal_value ring_size_div10_reciprocal;
         spinlock_t ring_lock;
 
         u32 ring_datasize;              /* < ring_size */
@@ -154,6 +156,16 @@ static inline u32 hv_get_bytes_to_write(const struct hv_ring_buffer_info *rbi)
         return write;
 }
 
+static inline u32 hv_get_avail_to_write_percent(
+                const struct hv_ring_buffer_info *rbi)
+{
+        u32 avail_write = hv_get_bytes_to_write(rbi);
+
+        return reciprocal_divide(
+                        (avail_write  << 3) + (avail_write << 1),
+                        rbi->ring_size_div10_reciprocal);
+}
+
 /*
  * VMBUS version is 32 bit entity broken up into
  * two 16 bit quantities: major_number. minor_number.