Commit e91e84fa authored Jun 20, 2013 by Jason Wang Committed by Greg Kroah-Hartman Jun 24, 2013

drivers: hv: check interrupt mask before read_index

This patches add a read barriers to force the driver to check the interrupt mask
before read_index. Otherwise we may lost a kick to host.

Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 0686ab7a

drivers/hv/ring_buffer.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -75,6 +75,8 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
		if (rbi->ring_buffer->interrupt_mask)
		return false;

		/* check interrupt_mask before read_index */
		rmb();
		/*
		* This is the only case we need to signal when the
		* ring transitions from being empty to non-empty.