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* [PATCH 1/1] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal()
@ 2013-03-29 21:30 K. Y. Srinivasan
  0 siblings, 0 replies; only message in thread
From: K. Y. Srinivasan @ 2013-03-29 21:30 UTC (permalink / raw)
  To: gregkh, linux-kernel, devel, olaf, apw, jasowang; +Cc: K. Y. Srinivasan, Stable

As part of updating the vmbus protocol, the function hv_need_to_signal()
was introduced. This functions helps optimize signalling from guest to
host. The newly added memory barrier is needed to ensure that we correctly
decide when to signal the host.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reported-by: Olaf Hering <olh@suse.de>

Cc: Stable <stable@vger.kernel.org>  (V3.8+)
---
 drivers/hv/ring_buffer.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index cafa72f..d6fbb577 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -71,6 +71,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
 
 static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
 {
+	smp_mb();
 	if (rbi->ring_buffer->interrupt_mask)
 		return false;
 
-- 
1.7.4.1


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2013-03-29 21:30 [PATCH 1/1] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal() K. Y. Srinivasan

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