On Thu, Jan 27, 2022 at 03:37:33PM -0600, Bob Pearson wrote:
> Add code to check if a QP is attached to one or more multicast groups
> when destroy_qp is called and return an error if so.
The core code already does some of this anyhow..
> diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
> index 949784198d80..34e3c52f0b72 100644
> +++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
> @@ -114,6 +114,7 @@ static int rxe_mcast_add_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
> grp->num_qp++;
> elem->qp = qp;
> elem->grp = grp;
> + atomic_inc(&qp->mcg_num);
eg what prevents qp from being concurrently destroyed here?
The core code because it doesn't allow a multicast group to be added
concurrently with destruction of a QP.
> +int rxe_qp_chk_destroy(struct rxe_qp *qp)
> +{
> + /* See IBA o10-2.2.3
> + * An attempt to destroy a QP while attached to a mcast group
> + * will fail immediately.
> + */
> + if (atomic_read(&qp->mcg_num)) {
> + pr_warn_once("Attempt to destroy QP while attached to multicast group\n");
> + return -EBUSY;
Don't print
But yes, I think drivers are expected to do this, though most likely
this is already happening for other reasons and this is mearly
protective against bugs.
Jason
