From 0519c520dc38e9950f4032d0f41f2b72b2c3c940 Mon Sep 17 00:00:00 2001 From: "Michael J. Ruhl" Date: Mon, 20 Mar 2017 17:24:45 -0700 Subject: [PATCH] IB/hfi1: Race hazard avoidance in user SDMA driver Set the errcode before the state and add the smb_wmb() to avoid a potential race condition with the user. Reviewed-by: Dennis Dalessandro Signed-off-by: Michael Ruhl Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/user_sdma.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c index e6811c4edc73..060e374ca37b 100644 --- a/drivers/infiniband/hw/hfi1/user_sdma.c +++ b/drivers/infiniband/hw/hfi1/user_sdma.c @@ -1615,9 +1615,10 @@ static inline void set_comp_state(struct hfi1_user_sdma_pkt_q *pq, { hfi1_cdbg(SDMA, "[%u:%u:%u:%u] Setting completion status %u %d", pq->dd->unit, pq->ctxt, pq->subctxt, idx, state, ret); - cq->comps[idx].status = state; if (state == ERROR) cq->comps[idx].errcode = -ret; + smp_wmb(); /* make sure errcode is visible first */ + cq->comps[idx].status = state; trace_hfi1_sdma_user_completion(pq->dd, pq->ctxt, pq->subctxt, idx, state, ret); } -- 2.30.2