From 845964515a76381e204d3399af82c149f8abcc1c Mon Sep 17 00:00:00 2001 From: Scott Feldman Date: Fri, 21 Nov 2008 21:29:01 -0800 Subject: [PATCH] enic: move wmb closer to where needed: before writing posted_index to hw Signed-off-by: Scott Feldman Signed-off-by: David S. Miller --- drivers/net/enic/enic_res.h | 4 ---- drivers/net/enic/vnic_rq.h | 9 ++++++++- 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 68534a29b7a..7bf272fa859 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 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) diff --git a/drivers/net/enic/vnic_wq.h b/drivers/net/enic/vnic_wq.h index 7081828d8a4..c826137dc65 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--; -- 2.46.0