RDMA/{cma, core}: Avoid callback on rdma_addr_cancel()

Currently rdma_addr_cancel() is an async operation, which notifies that
cancel is done by executing the callback function given during
rdma_resolve_ip(). If resolve_ip request is already completed than
callback is not executed.

Instead, now rdma_resolve_addr() and rdma_addr_cancel() simplified in
following ways.
1. rdma_addr_cancel() now a synchronous method. If request was
pending, after it is cancelled, no callback is notified.
2. rdma_resolve_addr() and respective addr_handler() callback doesn't
need to hold reference to cm_id.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/addr.c

@@ -660,6 +660,13 @@ int rdma_resolve_ip_route(struct sockaddr *src_addr,
 	return addr_resolve(src_in, dst_addr, addr, false, 0);
 }
 
+/**
+ * rdma_addr_cancel - Cancel resolve ip request
+ * @addr:	Pointer to address structure given previously
+ *		during rdma_resolve_ip().
+ * rdma_addr_cancel() is synchronous function which cancels any pending
+ * request if there is any.
+ */
 void rdma_addr_cancel(struct rdma_dev_addr *addr)
 {
 	struct addr_req *req, *temp_req;
@@ -687,11 +694,6 @@ void rdma_addr_cancel(struct rdma_dev_addr *addr)
 	 * guarentees no work is running and none will be started.
 	 */
 	cancel_delayed_work_sync(&found->work);
-
-	if (found->callback)
-		found->callback(-ECANCELED, (struct sockaddr *)&found->src_addr,
-			      found->addr, found->context);
-
 	kfree(found);
 }
 EXPORT_SYMBOL(rdma_addr_cancel);

drivers/infiniband/core/cma.c

@@ -2880,13 +2880,11 @@ static void addr_handler(int status, struct sockaddr *src_addr,
 	if (id_priv->id.event_handler(&id_priv->id, &event)) {
 		cma_exch(id_priv, RDMA_CM_DESTROYING);
 		mutex_unlock(&id_priv->handler_mutex);
-		cma_deref_id(id_priv);
 		rdma_destroy_id(&id_priv->id);
 		return;
 	}
 out:
 	mutex_unlock(&id_priv->handler_mutex);
-	cma_deref_id(id_priv);
 }
 
 static int cma_resolve_loopback(struct rdma_id_private *id_priv)
@@ -2983,7 +2981,6 @@ int rdma_resolve_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,
 		return -EINVAL;
 
 	memcpy(cma_dst_addr(id_priv), dst_addr, rdma_addr_size(dst_addr));
-	atomic_inc(&id_priv->refcount);
 	if (cma_any_addr(dst_addr)) {
 		ret = cma_resolve_loopback(id_priv);
 	} else {
@@ -3001,7 +2998,6 @@ int rdma_resolve_addr(struct rdma_cm_id *id, struct sockaddr *src_addr,
 	return 0;
 err:
 	cma_comp_exch(id_priv, RDMA_CM_ADDR_QUERY, RDMA_CM_ADDR_BOUND);
-	cma_deref_id(id_priv);
 	return ret;
 }
 EXPORT_SYMBOL(rdma_resolve_addr);