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>
This commit is contained in:
Jason Wang 2013-06-20 12:58:57 +08:00 committed by Greg Kroah-Hartman
parent 0686ab7a7d
commit e91e84fa4c

View File

@ -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.