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 | |
parent | cb3c766975985885e64e20cc72c4a36d90da2b30 (diff) | |
download | lwn-845964515a76381e204d3399af82c149f8abcc1c.tar.gz lwn-845964515a76381e204d3399af82c149f8abcc1c.zip |
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')
-rw-r--r-- | drivers/net/enic/enic_res.h | 4 | ||||
-rw-r--r-- | drivers/net/enic/vnic_rq.h | 9 | ||||
-rw-r--r-- | drivers/net/enic/vnic_wq.h | 9 |
3 files changed, 16 insertions, 6 deletions
diff --git a/drivers/net/enic/enic_res.h b/drivers/net/enic/enic_res.h index 68534a29b7ac..7bf272fa859b 100644 --- a/drivers/net/enic/enic_res.h +++ b/drivers/net/enic/enic_res.h @@ -58,8 +58,6 @@ static inline void enic_queue_wq_desc_ex(struct vnic_wq *wq, (u16)vlan_tag, 0 /* loopback */); - wmb(); - vnic_wq_post(wq, os_buf, dma_addr, len, sop, eop); } @@ -127,8 +125,6 @@ static inline void enic_queue_rq_desc(struct vnic_rq *rq, (u64)dma_addr | VNIC_PADDR_TARGET, type, (u16)len); - wmb(); - vnic_rq_post(rq, os_buf, os_buf_index, dma_addr, len); } diff --git a/drivers/net/enic/vnic_rq.h b/drivers/net/enic/vnic_rq.h index 82bfca67cc4d..fd0ef66d2e9f 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) diff --git a/drivers/net/enic/vnic_wq.h b/drivers/net/enic/vnic_wq.h index 7081828d8a42..c826137dc651 100644 --- a/drivers/net/enic/vnic_wq.h +++ b/drivers/net/enic/vnic_wq.h @@ -108,8 +108,15 @@ static inline void vnic_wq_post(struct vnic_wq *wq, buf->len = len; buf = buf->next; - if (eop) + if (eop) { + /* 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, &wq->ctrl->posted_index); + } wq->to_use = buf; wq->ring.desc_avail--; |