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[PATCHv6,net-next,26/31] iw_cxgb4: rmb() after reading valid gen bit

Message ID 1394639446-6504-27-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>

Some HW platforms can reorder read operations, so we must rmb() after
we see a valid gen bit in a CQE but before we read any other fields
from the CQE.

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

diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h
index edab0e9..67cd09ee 100644
--- a/drivers/infiniband/hw/cxgb4/t4.h
+++ b/drivers/infiniband/hw/cxgb4/t4.h
@@ -622,6 +622,7 @@  static inline int t4_next_hw_cqe(struct t4_cq *cq, struct t4_cqe **cqe)
 		printk(KERN_ERR MOD "cq overflow cqid %u\n", cq->cqid);
 		BUG_ON(1);
 	} else if (t4_valid_cqe(cq, &cq->queue[cq->cidx])) {
+		rmb();
 		*cqe = &cq->queue[cq->cidx];
 		ret = 0;
 	} else