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, 13 insertions, 8 deletions

diff --git a/net/rds/ib.c b/net/rds/ib.c
index a792d8a3872a..90212ed3edf1 100644
--- a/net/rds/ib.c
+++ b/net/rds/ib.c
@@ -127,19 +127,20 @@ void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
 		queue_work(rds_wq, &rds_ibdev->free_work);
 }
 
-static void rds_ib_add_one(struct ib_device *device)
+static int rds_ib_add_one(struct ib_device *device)
 {
 	struct rds_ib_device *rds_ibdev;
 	bool has_fr, has_fmr;
+	int ret;
 
 	/* Only handle IB (no iWARP) devices */
 	if (device->node_type != RDMA_NODE_IB_CA)
-		return;
+		return -EOPNOTSUPP;
 
 	rds_ibdev = kzalloc_node(sizeof(struct rds_ib_device), GFP_KERNEL,
 				 ibdev_to_node(device));
 	if (!rds_ibdev)
-		return;
+		return -ENOMEM;
 
 	spin_lock_init(&rds_ibdev->spinlock);
 	refcount_set(&rds_ibdev->refcount, 1);
@@ -182,12 +183,14 @@ static void rds_ib_add_one(struct ib_device *device)
 	if (!rds_ibdev->vector_load) {
 		pr_err("RDS/IB: %s failed to allocate vector memory\n",
 			__func__);
+		ret = -ENOMEM;
 		goto put_dev;
 	}
 
 	rds_ibdev->dev = device;
 	rds_ibdev->pd = ib_alloc_pd(device, 0);
 	if (IS_ERR(rds_ibdev->pd)) {
+		ret = PTR_ERR(rds_ibdev->pd);
 		rds_ibdev->pd = NULL;
 		goto put_dev;
 	}
@@ -195,12 +198,15 @@ static void rds_ib_add_one(struct ib_device *device)
 						   device->dma_device,
 						   sizeof(struct rds_header),
 						   L1_CACHE_BYTES, 0);
-	if (!rds_ibdev->rid_hdrs_pool)
+	if (!rds_ibdev->rid_hdrs_pool) {
+		ret = -ENOMEM;
 		goto put_dev;
+	}
 
 	rds_ibdev->mr_1m_pool =
 		rds_ib_create_mr_pool(rds_ibdev, RDS_IB_MR_1M_POOL);
 	if (IS_ERR(rds_ibdev->mr_1m_pool)) {
+		ret = PTR_ERR(rds_ibdev->mr_1m_pool);
 		rds_ibdev->mr_1m_pool = NULL;
 		goto put_dev;
 	}
@@ -208,6 +214,7 @@ static void rds_ib_add_one(struct ib_device *device)
 	rds_ibdev->mr_8k_pool =
 		rds_ib_create_mr_pool(rds_ibdev, RDS_IB_MR_8K_POOL);
 	if (IS_ERR(rds_ibdev->mr_8k_pool)) {
+		ret = PTR_ERR(rds_ibdev->mr_8k_pool);
 		rds_ibdev->mr_8k_pool = NULL;
 		goto put_dev;
 	}
@@ -227,12 +234,13 @@ static void rds_ib_add_one(struct ib_device *device)
 	refcount_inc(&rds_ibdev->refcount);
 
 	ib_set_client_data(device, &rds_ib_client, rds_ibdev);
-	refcount_inc(&rds_ibdev->refcount);
 
 	rds_ib_nodev_connect();
+	return 0;
 
 put_dev:
 	rds_ib_dev_put(rds_ibdev);
+	return ret;
 }
 
 /*
@@ -274,9 +282,6 @@ static void rds_ib_remove_one(struct ib_device *device, void *client_data)
 {
 	struct rds_ib_device *rds_ibdev = client_data;
 
-	if (!rds_ibdev)
-		return;
-
 	rds_ib_dev_shutdown(rds_ibdev);
 
 	/* stop connection attempts from getting a reference to this device. */