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, 10 insertions, 11 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index cd1181c39ed2..00b4f88b113e 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -146,7 +146,7 @@ module_param(ch_count, uint, 0444);
 MODULE_PARM_DESC(ch_count,
 		 "Number of RDMA channels to use for communication with an SRP target. Using more than one channel improves performance if the HCA supports multiple completion vectors. The default value is the minimum of four times the number of online CPU sockets and the number of completion vectors supported by the HCA.");
 
-static void srp_add_one(struct ib_device *device);
+static int srp_add_one(struct ib_device *device);
 static void srp_remove_one(struct ib_device *device, void *client_data);
 static void srp_rename_dev(struct ib_device *device, void *client_data);
 static void srp_recv_done(struct ib_cq *cq, struct ib_wc *wc);
@@ -4132,7 +4132,7 @@ static void srp_rename_dev(struct ib_device *device, void *client_data)
 	}
 }
 
-static void srp_add_one(struct ib_device *device)
+static int srp_add_one(struct ib_device *device)
 {
 	struct srp_device *srp_dev;
 	struct ib_device_attr *attr = &device->attrs;
@@ -4144,7 +4144,7 @@ static void srp_add_one(struct ib_device *device)
 
 	srp_dev = kzalloc(sizeof(*srp_dev), GFP_KERNEL);
 	if (!srp_dev)
-		return;
+		return -ENOMEM;
 
 	/*
 	 * Use the smallest page size supported by the HCA, down to a
@@ -4197,8 +4197,12 @@ static void srp_add_one(struct ib_device *device)
 
 	srp_dev->dev = device;
 	srp_dev->pd  = ib_alloc_pd(device, flags);
-	if (IS_ERR(srp_dev->pd))
-		goto free_dev;
+	if (IS_ERR(srp_dev->pd)) {
+		int ret = PTR_ERR(srp_dev->pd);
+
+		kfree(srp_dev);
+		return ret;
+	}
 
 	if (flags & IB_PD_UNSAFE_GLOBAL_RKEY) {
 		srp_dev->global_rkey = srp_dev->pd->unsafe_global_rkey;
@@ -4212,10 +4216,7 @@ static void srp_add_one(struct ib_device *device)
 	}
 
 	ib_set_client_data(device, &srp_client, srp_dev);
-	return;
-
-free_dev:
-	kfree(srp_dev);
+	return 0;
 }
 
 static void srp_remove_one(struct ib_device *device, void *client_data)
@@ -4225,8 +4226,6 @@ static void srp_remove_one(struct ib_device *device, void *client_data)
 	struct srp_target_port *target;
 
 	srp_dev = client_data;
-	if (!srp_dev)
-		return;
 
 	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
 		device_unregister(&host->dev);