RDMA/rdma_cm: Delete rdma_addr_client

The only thing it does is block module unload while work is posted from
rdma_resolve_ip().

However, this is not the right place to do this. The users of
rdma_resolve_ip() must ensure their own module does not unload until
rdma_resolve_ip() calls the callback, or until rdma_addr_cancel() is
called.

Similarly callers to rdma_addr_find_l2_eth_by_grh() must ensure their
module does not unload while they are calling code.

The only two users are already safe, so there is no need for this.

Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

Author: jgunthorpe

drivers/infiniband/core/addr.c

@@ -56,7 +56,6 @@ struct addr_req {
 	struct sockaddr_storage src_addr;
 	struct sockaddr_storage dst_addr;
 	struct rdma_dev_addr *addr;
-	struct rdma_addr_client *client;
 	void *context;
 	void (*callback)(int status, struct sockaddr *src_addr,
 			 struct rdma_dev_addr *addr, void *context);
@@ -220,28 +219,6 @@ int rdma_addr_size_kss(struct __kernel_sockaddr_storage *addr)
 }
 EXPORT_SYMBOL(rdma_addr_size_kss);
 
-static struct rdma_addr_client self;
-
-void rdma_addr_register_client(struct rdma_addr_client *client)
-{
-	atomic_set(&client->refcount, 1);
-	init_completion(&client->comp);
-}
-EXPORT_SYMBOL(rdma_addr_register_client);
-
-static inline void put_client(struct rdma_addr_client *client)
-{
-	if (atomic_dec_and_test(&client->refcount))
-		complete(&client->comp);
-}
-
-void rdma_addr_unregister_client(struct rdma_addr_client *client)
-{
-	put_client(client);
-	wait_for_completion(&client->comp);
-}
-EXPORT_SYMBOL(rdma_addr_unregister_client);
-
 void rdma_copy_addr(struct rdma_dev_addr *dev_addr,
 		    const struct net_device *dev,
 		    const unsigned char *dst_dev_addr)
@@ -605,14 +582,12 @@ static void process_one_req(struct work_struct *_work)
 		 */
 		cancel_delayed_work(&req->work);
 		list_del_init(&req->list);
-		put_client(req->client);
 		kfree(req);
 	}
 	spin_unlock_bh(&lock);
 }
 
-int rdma_resolve_ip(struct rdma_addr_client *client,
-		    struct sockaddr *src_addr, struct sockaddr *dst_addr,
+int rdma_resolve_ip(struct sockaddr *src_addr, struct sockaddr *dst_addr,
 		    struct rdma_dev_addr *addr, int timeout_ms,
 		    void (*callback)(int status, struct sockaddr *src_addr,
 				     struct rdma_dev_addr *addr, void *context),
@@ -644,8 +619,6 @@ int rdma_resolve_ip(struct rdma_addr_client *client,
 	req->addr = addr;
 	req->callback = callback;
 	req->context = context;
-	req->client = client;
-	atomic_inc(&client->refcount);
 	INIT_DELAYED_WORK(&req->work, process_one_req);
 	req->seq = (u32)atomic_inc_return(&ib_nl_addr_request_seq);
 
@@ -661,7 +634,6 @@ int rdma_resolve_ip(struct rdma_addr_client *client,
 		break;
 	default:
 		ret = req->status;
-		atomic_dec(&client->refcount);
 		goto err;
 	}
 	return ret;
@@ -722,7 +694,6 @@ void rdma_addr_cancel(struct rdma_dev_addr *addr)
 		found->callback(-ECANCELED, (struct sockaddr *)&found->src_addr,
 			      found->addr, found->context);
 
-	put_client(found->client);
 	kfree(found);
 }
 EXPORT_SYMBOL(rdma_addr_cancel);
@@ -761,8 +732,8 @@ int rdma_addr_find_l2_eth_by_grh(const union ib_gid *sgid,
 	dev_addr.net = &init_net;
 
 	init_completion(&ctx.comp);
-	ret = rdma_resolve_ip(&self, &sgid_addr._sockaddr, &dgid_addr._sockaddr,
-			&dev_addr, 1000, resolve_cb, &ctx);
+	ret = rdma_resolve_ip(&sgid_addr._sockaddr, &dgid_addr._sockaddr,
+			      &dev_addr, 1000, resolve_cb, &ctx);
 	if (ret)
 		return ret;
 
@@ -806,14 +777,13 @@ int addr_init(void)
 		return -ENOMEM;
 
 	register_netevent_notifier(&nb);
-	rdma_addr_register_client(&self);
 
 	return 0;
 }
 
 void addr_cleanup(void)
 {
-	rdma_addr_unregister_client(&self);
 	unregister_netevent_notifier(&nb);
 	destroy_workqueue(addr_wq);
+	WARN_ON(!list_empty(&req_list));
 }

drivers/infiniband/core/cma.c

@@ -156,7 +156,6 @@ static struct ib_client cma_client = {
 };
 
 static struct ib_sa_client sa_client;
-static struct rdma_addr_client addr_client;
 static LIST_HEAD(dev_list);
 static LIST_HEAD(listen_any_list);
 static DEFINE_MUTEX(lock);
@@ -2910,7 +2909,7 @@ int rdma_resolve_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,
 		if (dst_addr->sa_family == AF_IB) {
 			ret = cma_resolve_ib_addr(id_priv);
 		} else {
-			ret = rdma_resolve_ip(&addr_client, cma_src_addr(id_priv),
+			ret = rdma_resolve_ip(cma_src_addr(id_priv),
 					      dst_addr, &id->route.addr.dev_addr,
 					      timeout_ms, addr_handler, id_priv);
 		}
@@ -4547,7 +4546,6 @@ static int __init cma_init(void)
 		goto err_wq;
 
 	ib_sa_register_client(&sa_client);
-	rdma_addr_register_client(&addr_client);
 	register_netdevice_notifier(&cma_nb);
 
 	ret = ib_register_client(&cma_client);
@@ -4561,7 +4559,6 @@ static int __init cma_init(void)
 
 err:
 	unregister_netdevice_notifier(&cma_nb);
-	rdma_addr_unregister_client(&addr_client);
 	ib_sa_unregister_client(&sa_client);
 err_wq:
 	destroy_workqueue(cma_wq);
@@ -4574,7 +4571,6 @@ static void __exit cma_cleanup(void)
 	rdma_nl_unregister(RDMA_NL_RDMA_CM);
 	ib_unregister_client(&cma_client);
 	unregister_netdevice_notifier(&cma_nb);
-	rdma_addr_unregister_client(&addr_client);
 	ib_sa_unregister_client(&sa_client);
 	unregister_pernet_subsys(&cma_pernet_operations);
 	destroy_workqueue(cma_wq);

include/rdma/ib_addr.h

@@ -49,22 +49,6 @@
 #include <net/ipv6.h>
 #include <net/net_namespace.h>
 
-struct rdma_addr_client {
-	atomic_t refcount;
-	struct completion comp;
-};
-
-/**
- * rdma_addr_register_client - Register an address client.
- */
-void rdma_addr_register_client(struct rdma_addr_client *client);
-
-/**
- * rdma_addr_unregister_client - Deregister an address client.
- * @client: Client object to deregister.
- */
-void rdma_addr_unregister_client(struct rdma_addr_client *client);
-
 /**
  * struct rdma_dev_addr - Contains resolved RDMA hardware addresses
  * @src_dev_addr:	Source MAC address.
@@ -99,7 +83,6 @@ int rdma_translate_ip(const struct sockaddr *addr,
 /**
  * rdma_resolve_ip - Resolve source and destination IP addresses to
  *   RDMA hardware addresses.
- * @client: Address client associated with request.
  * @src_addr: An optional source address to use in the resolution.  If a
  *   source address is not provided, a usable address will be returned via
  *   the callback.
@@ -112,8 +95,7 @@ int rdma_translate_ip(const struct sockaddr *addr,
  *   or been canceled.  A status of 0 indicates success.
  * @context: User-specified context associated with the call.
  */
-int rdma_resolve_ip(struct rdma_addr_client *client,
-		    struct sockaddr *src_addr, struct sockaddr *dst_addr,
+int rdma_resolve_ip(struct sockaddr *src_addr, struct sockaddr *dst_addr,
 		    struct rdma_dev_addr *addr, int timeout_ms,
 		    void (*callback)(int status, struct sockaddr *src_addr,
 				     struct rdma_dev_addr *addr, void *context),