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[PATCHv6,net-next,27/31] iw_cxgb4: wc_wmb() needed after DB writes

Message ID 1394639446-6504-28-git-send-email-hariprasad@chelsio.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Hariprasad Shenai March 12, 2014, 3:50 p.m. UTC 
From: Steve Wise <swise@opengridcomputing.com>

Need to do an sfence after both the WC and regular PIDX DB write.
Otherwise the host might reorder things and cause work request corruption
(seen with NFSRDMA).

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
---
 drivers/infiniband/hw/cxgb4/t4.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h
index 67cd09ee..ace3154 100644
--- a/drivers/infiniband/hw/cxgb4/t4.h
+++ b/drivers/infiniband/hw/cxgb4/t4.h
@@ -470,12 +470,12 @@  static inline void t4_ring_sq_db(struct t4_wq *wq, u16 inc, u8 t5,
 			PDBG("%s: WC wq->sq.pidx = %d\n",
 			     __func__, wq->sq.pidx);
 			pio_copy(wq->sq.udb + 7, (void *)wqe);
-			wc_wmb();
 		} else {
 			PDBG("%s: DB wq->sq.pidx = %d\n",
 			     __func__, wq->sq.pidx);
 			writel(PIDX_T5(inc), wq->sq.udb);
 		}
+		wc_wmb();
 		return;
 	}
 	writel(QID(wq->sq.qid) | PIDX(inc), wq->db);
@@ -490,12 +490,12 @@  static inline void t4_ring_rq_db(struct t4_wq *wq, u16 inc, u8 t5,
 			PDBG("%s: WC wq->rq.pidx = %d\n",
 			     __func__, wq->rq.pidx);
 			pio_copy(wq->rq.udb + 7, (void *)wqe);
-			wc_wmb();
 		} else {
 			PDBG("%s: DB wq->rq.pidx = %d\n",
 			     __func__, wq->rq.pidx);
 			writel(PIDX_T5(inc), wq->rq.udb);
 		}
+		wc_wmb();
 		return;
 	}
 	writel(QID(wq->rq.qid) | PIDX(inc), wq->db);