Commit 99cfddb8 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/cma: Split apart the multiple uses of the same list heads 

Two list heads in the rdma_id_private are being used for multiple
purposes, to save a few bytes of memory. Give the different purposes
different names and union the memory that is clearly exclusive.

list splits into device_item and listen_any_item. device_item is threaded
onto the cma_device's list and listen_any goes onto the
listen_any_list. IDs doing any listen cannot have devices.

listen_list splits into listen_item and listen_list. listen_list is on the
parent listen any rdma_id_private and listen_item is on child listen that
is bound to a specific cma_dev.

Which name should be used in which case depends on the state and other
factors of the rdma_id_private. Remap all the confusing references to make
sense with the new names, so at least there is some hope of matching the
necessary preconditions with each access.

Link: https://lore.kernel.org/r/0-v1-a5ead4a0c19d+c3a-cma_list_head_jgg@nvidia.com


Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent c78d218f

drivers/infiniband/core/cma.c

+18 −16
Original line number Diff line number Diff line
@@ -453,7 +453,7 @@ static void _cma_attach_to_dev(struct rdma_id_private *id_priv, 
	id_priv->id.device = cma_dev->device;

	id_priv->id.route.addr.dev_addr.transport =

		rdma_node_get_transport(cma_dev->device->node_type);

	list_add_tail(&id_priv->list, &cma_dev->id_list);

	list_add_tail(&id_priv->device_item, &cma_dev->id_list);



	trace_cm_id_attach(id_priv, cma_dev->device);

}
@@ -470,7 +470,7 @@ static void cma_attach_to_dev(struct rdma_id_private *id_priv, 
static void cma_release_dev(struct rdma_id_private *id_priv)

{

	mutex_lock(&lock);

	list_del(&id_priv->list);

	list_del_init(&id_priv->device_item);

	cma_dev_put(id_priv->cma_dev);

	id_priv->cma_dev = NULL;

	id_priv->id.device = NULL;
@@ -854,6 +854,7 @@ __rdma_create_id(struct net *net, rdma_cm_event_handler event_handler, 
	init_completion(&id_priv->comp);

	refcount_set(&id_priv->refcount, 1);

	mutex_init(&id_priv->handler_mutex);

	INIT_LIST_HEAD(&id_priv->device_item);

	INIT_LIST_HEAD(&id_priv->listen_list);

	INIT_LIST_HEAD(&id_priv->mc_list);

	get_random_bytes(&id_priv->seq_num, sizeof id_priv->seq_num);
@@ -1647,7 +1648,7 @@ static struct rdma_id_private *cma_find_listener( 
				return id_priv;

			list_for_each_entry(id_priv_dev,

					    &id_priv->listen_list,

					    listen_list) {

					    listen_item) {

				if (id_priv_dev->id.device == cm_id->device &&

				    cma_match_net_dev(&id_priv_dev->id,

						      net_dev, req))
@@ -1756,14 +1757,15 @@ static void _cma_cancel_listens(struct rdma_id_private *id_priv) 
	 * Remove from listen_any_list to prevent added devices from spawning

	 * additional listen requests.

	 */

	list_del(&id_priv->list);

	list_del_init(&id_priv->listen_any_item);



	while (!list_empty(&id_priv->listen_list)) {

		dev_id_priv = list_entry(id_priv->listen_list.next,

					 struct rdma_id_private, listen_list);

		dev_id_priv =

			list_first_entry(&id_priv->listen_list,

					 struct rdma_id_private, listen_item);

		/* sync with device removal to avoid duplicate destruction */

		list_del_init(&dev_id_priv->list);

		list_del(&dev_id_priv->listen_list);

		list_del_init(&dev_id_priv->device_item);

		list_del_init(&dev_id_priv->listen_item);

		mutex_unlock(&lock);



		rdma_destroy_id(&dev_id_priv->id);
@@ -2564,7 +2566,7 @@ static int cma_listen_on_dev(struct rdma_id_private *id_priv, 
	ret = rdma_listen(&dev_id_priv->id, id_priv->backlog);

	if (ret)

		goto err_listen;

	list_add_tail(&dev_id_priv->listen_list, &id_priv->listen_list);

	list_add_tail(&dev_id_priv->listen_item, &id_priv->listen_list);

	return 0;

err_listen:

	/* Caller must destroy this after releasing lock */
@@ -2580,13 +2582,13 @@ static int cma_listen_on_all(struct rdma_id_private *id_priv) 
	int ret;



	mutex_lock(&lock);

	list_add_tail(&id_priv->list, &listen_any_list);

	list_add_tail(&id_priv->listen_any_item, &listen_any_list);

	list_for_each_entry(cma_dev, &dev_list, list) {

		ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);

		if (ret) {

			/* Prevent racing with cma_process_remove() */

			if (to_destroy)

				list_del_init(&to_destroy->list);

				list_del_init(&to_destroy->device_item);

			goto err_listen;

		}

	}
@@ -4895,7 +4897,7 @@ static int cma_netdev_callback(struct notifier_block *self, unsigned long event, 


	mutex_lock(&lock);

	list_for_each_entry(cma_dev, &dev_list, list)

		list_for_each_entry(id_priv, &cma_dev->id_list, list) {

		list_for_each_entry(id_priv, &cma_dev->id_list, device_item) {

			ret = cma_netdev_change(ndev, id_priv);

			if (ret)

				goto out;
@@ -4955,10 +4957,10 @@ static void cma_process_remove(struct cma_device *cma_dev) 
	mutex_lock(&lock);

	while (!list_empty(&cma_dev->id_list)) {

		struct rdma_id_private *id_priv = list_first_entry(

			&cma_dev->id_list, struct rdma_id_private, list);

			&cma_dev->id_list, struct rdma_id_private, device_item);



		list_del(&id_priv->listen_list);

		list_del_init(&id_priv->list);

		list_del_init(&id_priv->listen_item);

		list_del_init(&id_priv->device_item);

		cma_id_get(id_priv);

		mutex_unlock(&lock);
@@ -5035,7 +5037,7 @@ static int cma_add_one(struct ib_device *device) 


	mutex_lock(&lock);

	list_add_tail(&cma_dev->list, &dev_list);

	list_for_each_entry(id_priv, &listen_any_list, list) {

	list_for_each_entry(id_priv, &listen_any_list, listen_any_item) {

		ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);

		if (ret)

			goto free_listen;

drivers/infiniband/core/cma_priv.h

+9 −2
Original line number Diff line number Diff line
@@ -55,8 +55,15 @@ struct rdma_id_private { 


	struct rdma_bind_list	*bind_list;

	struct hlist_node	node;

	struct list_head	list; /* listen_any_list or cma_device.list */

	struct list_head	listen_list; /* per device listens */

	union {

		struct list_head device_item; /* On cma_device->id_list */

		struct list_head listen_any_item; /* On listen_any_list */

	};

	union {

		/* On rdma_id_private->listen_list */

		struct list_head listen_item;

		struct list_head listen_list;

	};

	struct cma_device	*cma_dev;

	struct list_head	mc_list;