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@xxxxxxxxxxxxx>
Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Reported-by: Olaf Hering <olh@xxxxxxx>
Cc: Stable <stable@xxxxxxxxxxxxxxx> (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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