diff options
| author | Scott Feldman <scofeldm@cisco.com> | 2008-11-21 21:29:01 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-11-21 21:29:01 -0800 |
| commit | 845964515a76381e204d3399af82c149f8abcc1c (patch) | |
| tree | 46f7f16c17294ccf56bd9f964e74a92cf7e7871e /drivers/net/enic/vnic_rq.h | |
| parent | cb3c766975985885e64e20cc72c4a36d90da2b30 (diff) | |
enic: move wmb closer to where needed: before writing posted_index to hw
Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/enic/vnic_rq.h')
| -rw-r--r-- | drivers/net/enic/vnic_rq.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/net/enic/vnic_rq.h b/drivers/net/enic/vnic_rq.h index 82bfca67cc4..fd0ef66d2e9 100644 --- a/drivers/net/enic/vnic_rq.h +++ b/drivers/net/enic/vnic_rq.h @@ -132,8 +132,15 @@ static inline void vnic_rq_post(struct vnic_rq *rq, #define VNIC_RQ_RETURN_RATE 0xf /* keep 2^n - 1 */ #endif - if ((buf->index & VNIC_RQ_RETURN_RATE) == 0) + if ((buf->index & VNIC_RQ_RETURN_RATE) == 0) { + /* Adding write memory barrier prevents compiler and/or CPU + * reordering, thus avoiding descriptor posting before + * descriptor is initialized. Otherwise, hardware can read + * stale descriptor fields. + */ + wmb(); iowrite32(buf->index, &rq->ctrl->posted_index); + } } static inline void vnic_rq_return_descs(struct vnic_rq *rq, unsigned int count) |