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Commit 44e75052 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/rdma_cm: Make rdma_addr_cancel into a fence 



Currently rdma_addr_cancel does not prevent the callback from being used,
this is surprising and hard to reason about. There does not appear to be a
bug here as the only user of this API does refcount properly, fixing it
only to increase clarity.

Signed-off-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent e19c0d23

drivers/infiniband/core/addr.c

+40 −18
Original line number Diff line number Diff line
@@ -585,29 +585,31 @@ static void process_one_req(struct work_struct *_work) 
		} else if (req->status == -ENODATA) {

			/* requeue the work for retrying again */

			spin_lock_bh(&lock);

			if (!list_empty(&req->list))

				set_timeout(req, req->timeout);

			spin_unlock_bh(&lock);

			return;

		}

	}

	spin_lock_bh(&lock);

	list_del(&req->list);

	spin_unlock_bh(&lock);



	req->callback(req->status, (struct sockaddr *)&req->src_addr,

		req->addr, req->context);

	req->callback = NULL;



	spin_lock_bh(&lock);

	if (!list_empty(&req->list)) {

		/*

		 * Although the work will normally have been canceled by the

		 * workqueue, it can still be requeued as long as it is on the

	 * req_list, so it could have been requeued before we grabbed &lock.

	 * We need to cancel it after it is removed from req_list to really be

	 * sure it is safe to free.

		 * req_list.

		 */

		cancel_delayed_work(&req->work);



	req->callback(req->status, (struct sockaddr *)&req->src_addr,

		req->addr, req->context);

		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,
@@ -691,17 +693,37 @@ int rdma_resolve_ip_route(struct sockaddr *src_addr, 
void rdma_addr_cancel(struct rdma_dev_addr *addr)

{

	struct addr_req *req, *temp_req;

	struct addr_req *found = NULL;



	spin_lock_bh(&lock);

	list_for_each_entry_safe(req, temp_req, &req_list, list) {

		if (req->addr == addr) {

			req->status = -ECANCELED;

			req->timeout = jiffies;

			set_timeout(req, req->timeout);

			/*

			 * Removing from the list means we take ownership of

			 * the req

			 */

			list_del_init(&req->list);

			found = req;

			break;

		}

	}

	spin_unlock_bh(&lock);



	if (!found)

		return;



	/*

	 * sync canceling the work after removing it from the req_list

	 * 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);



	put_client(found->client);

	kfree(found);

}

EXPORT_SYMBOL(rdma_addr_cancel);