From: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
To: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH 7/7] CQ overflow detection giving false positives
Date: Thu, 06 May 2010 18:06:52 -0500 [thread overview]
Message-ID: <20100506230652.25362.18848.stgit@build.ogc.int> (raw)
In-Reply-To: <20100506230619.25362.97591.stgit-T4OLL4TyM9aNDNWfRnPdfg@public.gmane.org>
CQ overflow detection needs to read the gen bit and the timestamp in
one read operation. Otherwise false overflows can result.
Signed-off-by: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
---
drivers/infiniband/hw/cxgb4/t4.h | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h
index 7f04dc5..d0e8af3 100644
--- a/drivers/infiniband/hw/cxgb4/t4.h
+++ b/drivers/infiniband/hw/cxgb4/t4.h
@@ -502,11 +502,12 @@ static inline int t4_valid_cqe(struct t4_cq *cq, struct t4_cqe *cqe)
static inline int t4_next_hw_cqe(struct t4_cq *cq, struct t4_cqe **cqe)
{
int ret = 0;
+ u64 bits_type_ts = be64_to_cpu(cq->queue[cq->cidx].bits_type_ts);
- if (t4_valid_cqe(cq, &cq->queue[cq->cidx])) {
+ if (G_CQE_GENBIT(bits_type_ts) == cq->gen) {
*cqe = &cq->queue[cq->cidx];
- cq->timestamp = CQE_TS(*cqe);
- } else if (CQE_TS(&cq->queue[cq->cidx]) > cq->timestamp)
+ cq->timestamp = G_CQE_TS(bits_type_ts);
+ } else if (G_CQE_TS(bits_type_ts) > cq->timestamp)
ret = -EOVERFLOW;
else
ret = -ENODATA;
--
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next prev parent reply other threads:[~2010-05-06 23:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 23:06 [PATCH 1/7] RDMA/cxgb4: Make ord/ird max for T4 match T3 Steve Wise
[not found] ` <20100506230619.25362.97591.stgit-T4OLL4TyM9aNDNWfRnPdfg@public.gmane.org>
2010-05-06 23:06 ` [PATCH 2/7] RDMA/cxgb4: shrink .text with compile-time init of handlers arrays Steve Wise
2010-05-06 23:06 ` [PATCH 3/7] RDMA/cxgb4: process ep timeouts in safe context Steve Wise
2010-05-06 23:06 ` [PATCH 4/7] RDMA/cxgb4: Use proper gfp_t values based on thread context Steve Wise
2010-05-06 23:06 ` [PATCH 5/7] RDMA/cxgb4: clean up a few printks Steve Wise
2010-05-06 23:06 ` [PATCH 6/7] RDMA/cxgb4: Avoid CQ arm overflows Steve Wise
2010-05-06 23:06 ` Steve Wise [this message]
[not found] ` <20100506230652.25362.18848.stgit-T4OLL4TyM9aNDNWfRnPdfg@public.gmane.org>
2010-05-10 15:42 ` [PATCH 7/7] CQ overflow detection giving false positives Roland Dreier
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