From: Steve Wise Date: Wed, 9 Apr 2014 14:38:26 +0000 (-0500) Subject: RDMA/cxgb4: rmb() after reading valid gen bit X-Git-Tag: v3.15-rc2~17^2~8 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=def4771f4bf428d39c7fe6006a9e1a20ee380d1e;p=linux-2.6-block.git RDMA/cxgb4: rmb() after reading valid gen bit 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 Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h index 931bfd105c49..1f329fac9801 100644 --- a/drivers/infiniband/hw/cxgb4/t4.h +++ b/drivers/infiniband/hw/cxgb4/t4.h @@ -620,6 +620,9 @@ 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])) { + + /* Ensure CQE is flushed to memory */ + rmb(); *cqe = &cq->queue[cq->cidx]; ret = 0; } else