[PATCH v2 4/9] hyperv: Replace smp_read_barrier_depends() with lockless_dereference()

[Pranith Kumar <bobby.prani@gmail.com>]

Recently lockless_dereference() was added which can be used in place of
hard-coding smp_read_barrier_depends(). The following PATCH makes the change.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
 include/linux/hyperv.h | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 08cfaff..06418b1 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -127,13 +127,12 @@ hv_get_ringbuffer_availbytes(struct hv_ring_buffer_info *rbi,
 			  u32 *read, u32 *write)
 {
 	u32 read_loc, write_loc, dsize;
-
-	smp_read_barrier_depends();
+	struct hv_ring_buffer_info *rbi_p = lockless_dereference(rbi);
 
 	/* Capture the read/write indices before they changed */
-	read_loc = rbi->ring_buffer->read_index;
-	write_loc = rbi->ring_buffer->write_index;
-	dsize = rbi->ring_datasize;
+	read_loc = rbi_p->ring_buffer->read_index;
+	write_loc = rbi_p->ring_buffer->write_index;
+	dsize = rbi_p->ring_datasize;
 
 	*write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
 		read_loc - write_loc;
-- 
1.9.1