RDMA/bnxt_re: Remove the qp from list only if the qp destroy succeeds

Driver crashes when destroy_qp is re-tried because of an error
returned. This is because the qp entry was removed from the qp list during
the first call.

Remove qp from the list only if destroy_qp returns success.

The driver will still trigger a WARN_ON due to the memory leaking, but at
least it isn't corrupting memory too.

Fixes: 8dae419f ("RDMA/bnxt_re: Refactor queue pair creation code")
Link: https://lore.kernel.org/r/1598292876-26529-2-git-send-email-selvin.xavier@broadcom.comSigned-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/bnxt_re/ib_verbs.c

@@ -752,12 +752,6 @@ static int bnxt_re_destroy_gsi_sqp(struct bnxt_re_qp *qp)
 	gsi_sqp = rdev->gsi_ctx.gsi_sqp;
 	gsi_sah = rdev->gsi_ctx.gsi_sah;
 
-	/* remove from active qp list */
-	mutex_lock(&rdev->qp_lock);
-	list_del(&gsi_sqp->list);
-	mutex_unlock(&rdev->qp_lock);
-	atomic_dec(&rdev->qp_count);
-
 	ibdev_dbg(&rdev->ibdev, "Destroy the shadow AH\n");
 	bnxt_qplib_destroy_ah(&rdev->qplib_res,
 			      &gsi_sah->qplib_ah,
@@ -772,6 +766,12 @@ static int bnxt_re_destroy_gsi_sqp(struct bnxt_re_qp *qp)
 	}
 	bnxt_qplib_free_qp_res(&rdev->qplib_res, &gsi_sqp->qplib_qp);
 
+	/* remove from active qp list */
+	mutex_lock(&rdev->qp_lock);
+	list_del(&gsi_sqp->list);
+	mutex_unlock(&rdev->qp_lock);
+	atomic_dec(&rdev->qp_count);
+
 	kfree(rdev->gsi_ctx.sqp_tbl);
 	kfree(gsi_sah);
 	kfree(gsi_sqp);
@@ -792,11 +792,6 @@ int bnxt_re_destroy_qp(struct ib_qp *ib_qp, struct ib_udata *udata)
 	unsigned int flags;
 	int rc;
 
-	mutex_lock(&rdev->qp_lock);
-	list_del(&qp->list);
-	mutex_unlock(&rdev->qp_lock);
-	atomic_dec(&rdev->qp_count);
-
 	bnxt_qplib_flush_cqn_wq(&qp->qplib_qp);
 
 	rc = bnxt_qplib_destroy_qp(&rdev->qplib_res, &qp->qplib_qp);
@@ -819,6 +814,11 @@ int bnxt_re_destroy_qp(struct ib_qp *ib_qp, struct ib_udata *udata)
 			goto sh_fail;
 	}
 
+	mutex_lock(&rdev->qp_lock);
+	list_del(&qp->list);
+	mutex_unlock(&rdev->qp_lock);
+	atomic_dec(&rdev->qp_count);
+
 	ib_umem_release(qp->rumem);
 	ib_umem_release(qp->sumem);