RDMA: Allow ib_client's to fail when add() is called

When a client is added it isn't allowed to fail, but all the client's have
various failure paths within their add routines.

This creates the very fringe condition where the client was added, failed
during add and didn't set the client_data. The core code will then still
call other client_data centric ops like remove(), rename(), get_nl_info(),
and get_net_dev_by_params() with NULL client_data - which is confusing and
unexpected.

If the add() callback fails, then do not call any more client ops for the
device, even remove.

Remove all the now redundant checks for NULL client_data in ops callbacks.

Update all the add() callbacks to return error codes
appropriately. EOPNOTSUPP is used for cases where the ULP does not support
the ib_device - eg because it only works with IB.

Link: https://lore.kernel.org/r/20200421172440.387069-1-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index e7e7c3c6e94a..2fad5f3fe093 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -547,18 +547,18 @@ static void smc_ib_cleanup_per_ibdev(struct smc_ib_device *smcibdev)
 static struct ib_client smc_ib_client;
 
 /* callback function for ib_register_client() */
-static void smc_ib_add_dev(struct ib_device *ibdev)
+static int smc_ib_add_dev(struct ib_device *ibdev)
 {
 	struct smc_ib_device *smcibdev;
 	u8 port_cnt;
 	int i;
 
 	if (ibdev->node_type != RDMA_NODE_IB_CA)
-		return;
+		return -EOPNOTSUPP;
 
 	smcibdev = kzalloc(sizeof(*smcibdev), GFP_KERNEL);
 	if (!smcibdev)
-		return;
+		return -ENOMEM;
 
 	smcibdev->ibdev = ibdev;
 	INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
@@ -583,6 +583,7 @@ static void smc_ib_add_dev(struct ib_device *ibdev)
 				       smcibdev->pnetid[i]);
 	}
 	schedule_work(&smcibdev->port_event_work);
+	return 0;
 }
 
 /* callback function for ib_unregister_client() */
@@ -590,9 +591,6 @@ static void smc_ib_remove_dev(struct ib_device *ibdev, void *client_data)
 {
 	struct smc_ib_device *smcibdev = client_data;
 
-	if (!smcibdev || smcibdev->ibdev != ibdev)
-		return;
-	ib_set_client_data(ibdev, &smc_ib_client, NULL);
 	spin_lock(&smc_ib_devices.lock);
 	list_del_init(&smcibdev->list); /* remove from smc_ib_devices */
 	spin_unlock(&smc_ib_devices.lock);