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authorK. Y. Srinivasan <kys@microsoft.com>2013-03-29 14:30:38 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-04-01 12:29:52 -0700
commit288fa3e022eb85fa151e0f9bcd15caeb81679af6 (patch)
tree18936a4994cce2e1a0c8a45577e45611077a9e45 /drivers/hv
parent945480b159aa0869bf5dadc07fdbae964882820b (diff)
Drivers: hv: vmbus: Fix a bug in hv_need_to_signal()
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+) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/ring_buffer.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index cafa72ffdc30..d6fbb5772b8d 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;

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