Commit 0519c520 authored by Michael J. Ruhl's avatar Michael J. Ruhl Committed by Doug Ledford

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: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarMichael Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent ec8a1423
...@@ -1615,9 +1615,10 @@ static inline void set_comp_state(struct hfi1_user_sdma_pkt_q *pq, ...@@ -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", hfi1_cdbg(SDMA, "[%u:%u:%u:%u] Setting completion status %u %d",
pq->dd->unit, pq->ctxt, pq->subctxt, idx, state, ret); pq->dd->unit, pq->ctxt, pq->subctxt, idx, state, ret);
cq->comps[idx].status = state;
if (state == ERROR) if (state == ERROR)
cq->comps[idx].errcode = -ret; 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, trace_hfi1_sdma_user_completion(pq->dd, pq->ctxt, pq->subctxt,
idx, state, ret); idx, state, ret);
} }
......
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