From: K. Y. Srinivasan <kys@microsoft.com>
Date: Mon, 6 Jun 2011 22:49:52 +0000 (-0700)
Subject: Staging: hv: vmbus: Introduce read dependency in hv_get_ringbuffer_availbytes()
X-Git-Tag: next-20110726~5^2~568^2~54
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=df2a4a711478f5fc28b3ac85f07e191591e31eb0;p=karo-tx-linux.git

Staging: hv: vmbus: Introduce read dependency in hv_get_ringbuffer_availbytes()

Introduce read dependency in hv_get_ringbuffer_availbytes().

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Abhishek Kane <v-abkane@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/staging/hv/ring_buffer.c b/drivers/staging/hv/ring_buffer.c
index 932af1a01a1e..8b625533fe43 100644
--- a/drivers/staging/hv/ring_buffer.c
+++ b/drivers/staging/hv/ring_buffer.c
@@ -50,6 +50,8 @@ hv_get_ringbuffer_availbytes(struct hv_ring_buffer_info *rbi,
 {
 	u32 read_loc, write_loc;
 
+	smp_read_barrier_depends();
+
 	/* Capture the read/write indices before they changed */
 	read_loc = rbi->ring_buffer->read_index;
 	write_loc = rbi->ring_buffer->write_index;