RDMA/rxe: Remove qp->grp_lock and qp->grp_list

Since it is no longer required to cleanup attachments to multicast
groups when a QP is destroyed qp->grp_lock and qp->grp_list are
no longer needed and are removed.

Link: https://lore.kernel.org/r/20220127213755.31697-7-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_mcast.c

@@ -88,7 +88,6 @@ static int rxe_mcast_add_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
 	struct rxe_mca *elem;
 
 	/* check to see of the qp is already a member of the group */
-	spin_lock_bh(&qp->grp_lock);
 	spin_lock_bh(&grp->mcg_lock);
 	list_for_each_entry(elem, &grp->qp_list, qp_list) {
 		if (elem->qp == qp) {
@@ -113,16 +112,13 @@ 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);
 
 	list_add(&elem->qp_list, &grp->qp_list);
-	list_add(&elem->grp_list, &qp->grp_list);
 
 	err = 0;
 out:
 	spin_unlock_bh(&grp->mcg_lock);
-	spin_unlock_bh(&qp->grp_lock);
 	return err;
 }
 
@@ -136,18 +132,15 @@ static int rxe_mcast_drop_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
 	if (!grp)
 		goto err1;
 
-	spin_lock_bh(&qp->grp_lock);
 	spin_lock_bh(&grp->mcg_lock);
 
 	list_for_each_entry_safe(elem, tmp, &grp->qp_list, qp_list) {
 		if (elem->qp == qp) {
 			list_del(&elem->qp_list);
-			list_del(&elem->grp_list);
 			grp->num_qp--;
 			atomic_dec(&qp->mcg_num);
 
 			spin_unlock_bh(&grp->mcg_lock);
-			spin_unlock_bh(&qp->grp_lock);
 			rxe_drop_ref(elem);
 			rxe_drop_ref(grp);	/* ref held by QP */
 			rxe_drop_ref(grp);	/* ref from get_key */
@@ -156,7 +149,6 @@ static int rxe_mcast_drop_grp_elem(struct rxe_dev *rxe, struct rxe_qp *qp,
 	}
 
 	spin_unlock_bh(&grp->mcg_lock);
-	spin_unlock_bh(&qp->grp_lock);
 	rxe_drop_ref(grp);			/* ref from get_key */
 err1:
 	return -EINVAL;

drivers/infiniband/sw/rxe/rxe_qp.c

@@ -188,9 +188,6 @@ static void rxe_qp_init_misc(struct rxe_dev *rxe, struct rxe_qp *qp,
 		break;
 	}
 
-	INIT_LIST_HEAD(&qp->grp_list);
-
-	spin_lock_init(&qp->grp_lock);
 	spin_lock_init(&qp->state_lock);
 
 	atomic_set(&qp->ssn, 0);

drivers/infiniband/sw/rxe/rxe_verbs.h

@@ -232,9 +232,6 @@ struct rxe_qp {
 	struct rxe_av		pri_av;
 	struct rxe_av		alt_av;
 
-	/* list of mcast groups qp has joined (for cleanup) */
-	struct list_head	grp_list;
-	spinlock_t		grp_lock; /* guard grp_list */
 	atomic_t		mcg_num;
 
 	struct sk_buff_head	req_pkts;
@@ -368,9 +365,7 @@ struct rxe_mcg {
 struct rxe_mca {
 	struct rxe_pool_elem	elem;
 	struct list_head	qp_list;
-	struct list_head	grp_list;
 	struct rxe_qp		*qp;
-	struct rxe_mcg		*grp;
 };
 
 struct rxe_port {