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: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 704ce595542c5735e2390ebedc2cf2697333b8e5..835ac54d4a24c8f5cb1a1184f012926c5a6aa1f2 100644 (file)
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -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;

diff --git a/drivers/infiniband/core/cma_priv.h b/drivers/infiniband/core/cma_priv.h
index f92f101ea9818f8c1ecf11375353103dce234858..757a0ef798729496a066cf618329593fe41e04f8 100644 (file)
--- a/drivers/infiniband/core/cma_priv.h
+++ b/drivers/infiniband/core/cma_priv.h
@@ -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;