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 <[email protected]> Reviewed-by: Haiyang Zhang <[email protected]> Reported-by: Olaf Hering <[email protected]> Cc: Stable <[email protected]> (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 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
