Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 048/115] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal() | Date | Mon, 6 May 2013 13:44:44 -0700 |
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3.9-stable review patch. If anyone has any objections, please let me know.
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From: "K. Y. Srinivasan" <kys@microsoft.com>
commit 288fa3e022eb85fa151e0f9bcd15caeb81679af6 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/hv/ring_buffer.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -71,6 +71,7 @@ u32 hv_end_read(struct hv_ring_buffer_in 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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