[RFC PATCH v9 15/26] RDMA/rxe: Add code to cleanup mcast memory

[Bob Pearson <rpearsonhpe@gmail.com>]

Well behaved applications will free all memory allocated by multicast
but programs which do not clean up properly can leave behind allocated
memory when the rxe driver is unloaded. This patch walks the red-black
tree holding multicast group elements and then walks the list of attached
qp's freeing the mca's and finally the mcg's.

Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
---
 drivers/infiniband/sw/rxe/rxe.c       |  2 ++
 drivers/infiniband/sw/rxe/rxe_loc.h   |  1 +
 drivers/infiniband/sw/rxe/rxe_mcast.c | 31 +++++++++++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
index c560d467a972..74c5521e9b3d 100644
--- a/drivers/infiniband/sw/rxe/rxe.c
+++ b/drivers/infiniband/sw/rxe/rxe.c
@@ -29,6 +29,8 @@ void rxe_dealloc(struct ib_device *ib_dev)
 	rxe_pool_cleanup(&rxe->mr_pool);
 	rxe_pool_cleanup(&rxe->mw_pool);
 
+	rxe_cleanup_mcast(rxe);
+
 	if (rxe->tfm)
 		crypto_free_shash(rxe->tfm);
 }
diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index 409efeecd581..0bc1b7e2877c 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -44,6 +44,7 @@ struct rxe_mcg *rxe_lookup_mcg(struct rxe_dev *rxe, union ib_gid *mgid);
 int rxe_attach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid);
 int rxe_detach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid);
 void rxe_cleanup_mcg(struct kref *kref);
+void rxe_cleanup_mcast(struct rxe_dev *rxe);
 
 /* rxe_mmap.c */
 struct rxe_mmap_info {
diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
index d01456052879..49cc1ad05bba 100644
--- a/drivers/infiniband/sw/rxe/rxe_mcast.c
+++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
@@ -336,3 +336,34 @@ int rxe_detach_mcast(struct ib_qp *ibqp, union ib_gid *mgid, u16 mlid)
 
 	return rxe_mcast_drop_grp_elem(rxe, qp, mgid);
 }
+
+/**
+ * rxe_cleanup_mcast - cleanup all resources held by mcast
+ * @rxe: rxe object
+ *
+ * Called when rxe device is unloaded. Walk red-black tree to
+ * find all mcg's and then walk mcg->qp_list to find all mca's and
+ * free them. These should have been freed already if apps are
+ * well behaved.
+ */
+void rxe_cleanup_mcast(struct rxe_dev *rxe)
+{
+	struct rb_root *root = &rxe->mcg_tree;
+	struct rb_node *node, *next;
+	struct rxe_mcg *mcg;
+	struct rxe_mca *mca, *tmp;
+
+	for (node = rb_first(root); node; node = next) {
+		next = rb_next(node);
+		mcg = rb_entry(node, typeof(*mcg), node);
+
+		spin_lock_bh(&rxe->mcg_lock);
+		list_for_each_entry_safe(mca, tmp, &mcg->qp_list, qp_list)
+			kfree(mca);
+
+		__rxe_remove_mcg(mcg);
+		spin_unlock_bh(&rxe->mcg_lock);
+
+		kfree(mcg);
+	}
+}
-- 
2.32.0