On Tue, Aug 07, 2018 at 10:02:03AM +0000, Kalderon, Michal wrote:
> > From: linux-rdma-owner@xxxxxxxxxxxxxxx <linux-rdma-
> > owner@xxxxxxxxxxxxxxx> On Behalf Of Jason Gunthorpe
> >
> > On Sun, Jul 29, 2018 at 01:16:10PM +0300, Yuval Bason wrote:
> >
> > > diff --git a/drivers/infiniband/hw/qedr/qedr_iw_cm.c
> > > b/drivers/infiniband/hw/qedr/qedr_iw_cm.c
> > > index 26dc374..505fa36 100644
> > > +++ b/drivers/infiniband/hw/qedr/qedr_iw_cm.c
> > > @@ -491,7 +491,7 @@ int qedr_iw_connect(struct iw_cm_id *cm_id,
> > struct iw_cm_conn_param *conn_param)
> > > int rc = 0;
> > > int i;
> > >
> > > - qp = idr_find(&dev->qpidr, conn_param->qpn);
> > > + qp = idr_find(&dev->qpidr.idr, conn_param->qpn);
> > >
> > > laddr = (struct sockaddr_in *)&cm_id->m_local_addr;
> > > raddr = (struct sockaddr_in *)&cm_id->m_remote_addr; @@ -679,7
> > > +679,7 @@ int qedr_iw_accept(struct iw_cm_id *cm_id, struct
> > > iw_cm_conn_param *conn_param)
> >
> > [..]
> >
> > > @@ -2279,8 +2275,9 @@ int qedr_destroy_qp(struct ib_qp *ibqp)
> > >
> > > qedr_free_qp_resources(dev, qp);
> > >
> > > - if (atomic_dec_and_test(&qp->refcnt)) {
> > > - qedr_idr_remove(dev, qp->qp_id);
> > > + if (atomic_dec_and_test(&qp->refcnt) &&
> > > + rdma_protocol_iwarp(&dev->ibdev, 1)) {
> > > + qedr_idr_remove(dev, &dev->qpidr, qp->qp_id);
> > > kfree(qp);
> >
> > So what prevents kfree from racing with the idr_find above? Looks like
> > noting.
>
> Hi Jason,
> This is the QP idr, and the use case here is for iWARP rdma
> connection flow. The flows here are part of the rdma-cm for iWARP
> and the races here are dealt with by locking and ref-counting in the
> rdma-cm.
How?
Jason
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