> From: Sinan Kaya [mailto:okaya@xxxxxxxxxxxxxx] > Sent: Tuesday, March 20, 2018 4:48 AM > > Code includes wmb() followed by writel() in multiple places. writel() already > has a barrier on some architectures like arm64. > > This ends up CPU observing two barriers back to back before executing the > register write. > > Since code already has an explicit barrier call, changing writel() to > writel_relaxed(). > > Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx> > --- > drivers/infiniband/hw/qedr/verbs.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/infiniband/hw/qedr/verbs.c > b/drivers/infiniband/hw/qedr/verbs.c > index ccd55f4..db60360 100644 > --- a/drivers/infiniband/hw/qedr/verbs.c > +++ b/drivers/infiniband/hw/qedr/verbs.c > @@ -860,7 +860,7 @@ static void doorbell_cq(struct qedr_cq *cq, u32 cons, > u8 flags) > wmb(); > cq->db.data.agg_flags = flags; > cq->db.data.value = cpu_to_le32(cons); > - writeq(cq->db.raw, cq->db_addr); > + writeq_relaxed(cq->db.raw, cq->db_addr); > > /* Make sure write would stick */ > mmiowb(); > @@ -3338,7 +3338,7 @@ int qedr_post_recv(struct ib_qp *ibqp, struct > ib_recv_wr *wr, > > qp->rq.db_data.data.value++; > > - writel(qp->rq.db_data.raw, qp->rq.db); > + writel_relaxed(qp->rq.db_data.raw, qp->rq.db); > > /* Make sure write sticks */ > mmiowb(); > -- > 2.7.4 Acked-by: Michal Kalderon <Michal.Kalderon@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
