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IB/hfi1: Race hazard avoidance in user SDMA driver

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Set the errcode before the state and add the smb_wmb() to avoid a
potential race condition with the user.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Michael Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Michael J. Ruhl 2017-03-20 17:24:45 -07:00 committed by Doug Ledford
parent ec8a142327
commit 0519c520dc
1 changed files with 2 additions and 1 deletions
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3
drivers/infiniband/hw/hfi1/user_sdma.c
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@ -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);
}