IB: Improve uverbs_cleanup_ucontext algorithm

Improve uverbs_cleanup_ucontext algorithm to work properly when the
topology graph of the objects cannot be determined at compile time.  This
is the case with objects created via the devx interface in mlx5.

Typically uverbs objects must be created in a strict topologically sorted
order, so that LIFO ordering will generally cause them to be freed
properly. There are only a few cases (eg memory windows) where objects can
point to things out of the strict LIFO order.

Instead of using an explicit ordering scheme where the HW destroy is not
allowed to fail, go over the list multiple times and allow the destroy
function to fail. If progress halts then a final, desperate, cleanup is
done before leaking the memory. This indicates a driver bug.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 36 insertions, 26 deletions

diff --git a/drivers/infiniband/core/uverbs_std_types.c b/drivers/infiniband/core/uverbs_std_types.c
index c50d73845a2a..c7f93b205c70 100644
--- a/drivers/infiniband/core/uverbs_std_types.c
+++ b/drivers/infiniband/core/uverbs_std_types.c
@@ -77,6 +77,13 @@ static int uverbs_free_qp(struct ib_uobject *uobject,
 		container_of(uobject, struct ib_uqp_object, uevent.uobject);
 	int ret;
 
+	/*
+	 * If this is a user triggered destroy then do not allow destruction
+	 * until the user cleans up all the mcast bindings. Unlike in other
+	 * places we forcibly clean up the mcast attachments for !DESTROY
+	 * because the mcast attaches are not ubojects and will not be
+	 * destroyed by anything else during cleanup processing.
+	 */
 	if (why == RDMA_REMOVE_DESTROY) {
 		if (!list_empty(&uqp->mcast_list))
 			return -EBUSY;
@@ -85,7 +92,7 @@ static int uverbs_free_qp(struct ib_uobject *uobject,
 	}
 
 	ret = ib_destroy_qp(qp);
-	if (ret && why == RDMA_REMOVE_DESTROY)
+	if (ib_is_destroy_retryable(ret, why, uobject))
 		return ret;
 
 	if (uqp->uxrcd)
@@ -103,8 +110,10 @@ static int uverbs_free_rwq_ind_tbl(struct ib_uobject *uobject,
 	int ret;
 
 	ret = ib_destroy_rwq_ind_table(rwq_ind_tbl);
-	if (!ret || why != RDMA_REMOVE_DESTROY)
-		kfree(ind_tbl);
+	if (ib_is_destroy_retryable(ret, why, uobject))
+		return ret;
+
+	kfree(ind_tbl);
 	return ret;
 }
 
@@ -117,8 +126,10 @@ static int uverbs_free_wq(struct ib_uobject *uobject,
 	int ret;
 
 	ret = ib_destroy_wq(wq);
-	if (!ret || why != RDMA_REMOVE_DESTROY)
-		ib_uverbs_release_uevent(uobject->context->ufile, &uwq->uevent);
+	if (ib_is_destroy_retryable(ret, why, uobject))
+		return ret;
+
+	ib_uverbs_release_uevent(uobject->context->ufile, &uwq->uevent);
 	return ret;
 }
 
@@ -132,8 +143,7 @@ static int uverbs_free_srq(struct ib_uobject *uobject,
 	int ret;
 
 	ret = ib_destroy_srq(srq);
-
-	if (ret && why == RDMA_REMOVE_DESTROY)
+	if (ib_is_destroy_retryable(ret, why, uobject))
 		return ret;
 
 	if (srq_type == IB_SRQT_XRC) {
@@ -155,12 +165,12 @@ static int uverbs_free_xrcd(struct ib_uobject *uobject,
 		container_of(uobject, struct ib_uxrcd_object, uobject);
 	int ret;
 
+	ret = ib_destroy_usecnt(&uxrcd->refcnt, why, uobject);
+	if (ret)
+		return ret;
+
 	mutex_lock(&uobject->context->ufile->device->xrcd_tree_mutex);
-	if (why == RDMA_REMOVE_DESTROY && atomic_read(&uxrcd->refcnt))
-		ret = -EBUSY;
-	else
-		ret = ib_uverbs_dealloc_xrcd(uobject->context->ufile->device,
-					     xrcd, why);
+	ret = ib_uverbs_dealloc_xrcd(uobject, xrcd, why);
 	mutex_unlock(&uobject->context->ufile->device->xrcd_tree_mutex);
 
 	return ret;
@@ -170,9 +180,11 @@ static int uverbs_free_pd(struct ib_uobject *uobject,
 			  enum rdma_remove_reason why)
 {
 	struct ib_pd *pd = uobject->object;
+	int ret;
 
-	if (why == RDMA_REMOVE_DESTROY && atomic_read(&pd->usecnt))
-		return -EBUSY;
+	ret = ib_destroy_usecnt(&pd->usecnt, why, uobject);
+	if (ret)
+		return ret;
 
 	ib_dealloc_pd((struct ib_pd *)uobject->object);
 	return 0;
@@ -249,44 +261,42 @@ void create_udata(struct uverbs_attr_bundle *ctx, struct ib_udata *udata)
 }
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_COMP_CHANNEL,
-			    &UVERBS_TYPE_ALLOC_FD(0,
-						  sizeof(struct ib_uverbs_completion_event_file),
+			    &UVERBS_TYPE_ALLOC_FD(sizeof(struct ib_uverbs_completion_event_file),
 						  uverbs_hot_unplug_completion_event_file,
 						  &uverbs_event_fops,
 						  "[infinibandevent]", O_RDONLY));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_QP,
-			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uqp_object), 0,
+			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uqp_object),
 						      uverbs_free_qp));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_MW,
-			    &UVERBS_TYPE_ALLOC_IDR(0, uverbs_free_mw));
+			    &UVERBS_TYPE_ALLOC_IDR(uverbs_free_mw));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_SRQ,
-			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_usrq_object), 0,
+			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_usrq_object),
 						      uverbs_free_srq));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_AH,
-			    &UVERBS_TYPE_ALLOC_IDR(0, uverbs_free_ah));
+			    &UVERBS_TYPE_ALLOC_IDR(uverbs_free_ah));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_FLOW,
 			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uflow_object),
-						      0, uverbs_free_flow));
+						      uverbs_free_flow));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_WQ,
-			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uwq_object), 0,
+			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uwq_object),
 						      uverbs_free_wq));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_RWQ_IND_TBL,
-			    &UVERBS_TYPE_ALLOC_IDR(0, uverbs_free_rwq_ind_tbl));
+			    &UVERBS_TYPE_ALLOC_IDR(uverbs_free_rwq_ind_tbl));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_XRCD,
-			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uxrcd_object), 0,
+			    &UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uxrcd_object),
 						      uverbs_free_xrcd));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_PD,
-			    /* 2 is used in order to free the PD after MRs */
-			    &UVERBS_TYPE_ALLOC_IDR(2, uverbs_free_pd));
+			    &UVERBS_TYPE_ALLOC_IDR(uverbs_free_pd));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_DEVICE, NULL);