patch "Drivers: hv: vmbus: Fix a bug in hv_need_to_signal()" added to char-misc tree

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This is a note to let you know that I've just added the patch titled

    Drivers: hv: vmbus: Fix a bug in hv_need_to_signal()

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


>From 288fa3e022eb85fa151e0f9bcd15caeb81679af6 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Date: Fri, 29 Mar 2013 14:30:38 -0700
Subject: 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@xxxxxxxxxxxxx>
Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Reported-by: Olaf Hering <olh@xxxxxxx>
Cc: Stable <stable@xxxxxxxxxxxxxxx>  (V3.8+)
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/hv/ring_buffer.c | 1 +
 1 file changed, 1 insertion(+)

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;
 
-- 
1.8.1.rc1.5.g7e0651a


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