Re: [PATCH v2 for-rc 5/6] RDMA/bnxt_re: synchronize the qp-handle table array

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Oct 07, 2024 at 11:20:24AM +0530, Selvin Xavier wrote:
> On Sat, Oct 5, 2024 at 12:57 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
> >
> > On Wed, Sep 18, 2024 at 08:06:00PM -0700, Selvin Xavier wrote:
> >
> > > diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
> > > index 5bef9b4..85bfedc 100644
> > > --- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
> > > +++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
> > > @@ -634,17 +634,21 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
> > >       case CREQ_QP_EVENT_EVENT_QP_ERROR_NOTIFICATION:
> > >               err_event = (struct creq_qp_error_notification *)qp_event;
> > >               qp_id = le32_to_cpu(err_event->xid);
> > > +             spin_lock_nested(&rcfw->tbl_lock, SINGLE_DEPTH_NESTING);
> >
> > Why would you need this lockdep annotation? tbl_lock doesn't look
> > nested into itself to me.
> bnxt_qplib_process_qp_event is always called with a spinlock
> (hwq->lock ) in the caller. i.e. bnxt_qplib_service_creq. I have used
> the nested variant because of this.

That is not what nested is for. Nested different locks are fine, you
only need nested if you are nesting the same lock

Jason