>-----Original Message----- >From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma- >owner@xxxxxxxxxxxxxxx] On Behalf Of Andrea Parri >Sent: Monday, April 29, 2019 4:15 PM >To: linux-kernel@xxxxxxxxxxxxxxx >Cc: Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx>; >stable@xxxxxxxxxxxxxxx; Dalessandro, Dennis ><dennis.dalessandro@xxxxxxxxx>; Marciniszyn, Mike ><mike.marciniszyn@xxxxxxxxx>; Doug Ledford <dledford@xxxxxxxxxx>; >Jason Gunthorpe <jgg@xxxxxxxx>; linux-rdma@xxxxxxxxxxxxxxx >Subject: [PATCH 5/5] IB/hfi1: Fix improper uses of smp_mb__before_atomic() > >This barrier only applies to the read-modify-write operations; in >particular, it does not apply to the atomic_read() primitive. > >Replace the barrier with an smp_mb(). This is one of a couple of barrier issues that we are currently looking into. See: [PATCH for-next 6/9] IB/rdmavt: Add new completion inline We will take a look at this one as well. Thanks, Mike >Fixes: 856cc4c237add ("IB/hfi1: Add the capability for reserved operations") >Cc: stable@xxxxxxxxxxxxxxx >Reported-by: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx> >Reported-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> >Signed-off-by: Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx> >Cc: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> >Cc: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx> >Cc: Doug Ledford <dledford@xxxxxxxxxx> >Cc: Jason Gunthorpe <jgg@xxxxxxxx> >Cc: linux-rdma@xxxxxxxxxxxxxxx >--- > drivers/infiniband/sw/rdmavt/qp.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > >diff --git a/drivers/infiniband/sw/rdmavt/qp.c >b/drivers/infiniband/sw/rdmavt/qp.c >index a34b9a2a32b60..b64fd151d31fb 100644 >--- a/drivers/infiniband/sw/rdmavt/qp.c >+++ b/drivers/infiniband/sw/rdmavt/qp.c >@@ -1863,11 +1863,11 @@ static inline int rvt_qp_is_avail( > u32 reserved_used; > > /* see rvt_qp_wqe_unreserve() */ >- smp_mb__before_atomic(); >+ smp_mb(); > reserved_used = atomic_read(&qp->s_reserved_used); > if (unlikely(reserved_op)) { > /* see rvt_qp_wqe_unreserve() */ >- smp_mb__before_atomic(); >+ smp_mb(); > if (reserved_used >= rdi->dparms.reserved_operations) > return -ENOMEM; > return 0; >@@ -1882,7 +1882,7 @@ static inline int rvt_qp_is_avail( > avail = slast - qp->s_head; > > /* see rvt_qp_wqe_unreserve() */ >- smp_mb__before_atomic(); >+ smp_mb(); > reserved_used = atomic_read(&qp->s_reserved_used); > avail = avail - 1 - > (rdi->dparms.reserved_operations - reserved_used); >-- >2.7.4
