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, 15 deletions

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 9d02d8088f1c..7ed38d1cb997 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -3101,7 +3101,7 @@ static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
  * srpt_add_one - InfiniBand device addition callback function
  * @device: Describes a HCA.
  */
-static void srpt_add_one(struct ib_device *device)
+static int srpt_add_one(struct ib_device *device)
 {
 	struct srpt_device *sdev;
 	struct srpt_port *sport;
@@ -3112,14 +3112,16 @@ static void srpt_add_one(struct ib_device *device)
 	sdev = kzalloc(struct_size(sdev, port, device->phys_port_cnt),
 		       GFP_KERNEL);
 	if (!sdev)
-		goto err;
+		return -ENOMEM;
 
 	sdev->device = device;
 	mutex_init(&sdev->sdev_mutex);
 
 	sdev->pd = ib_alloc_pd(device, 0);
-	if (IS_ERR(sdev->pd))
+	if (IS_ERR(sdev->pd)) {
+		ret = PTR_ERR(sdev->pd);
 		goto free_dev;
+	}
 
 	sdev->lkey = sdev->pd->local_dma_lkey;
 
@@ -3135,6 +3137,7 @@ static void srpt_add_one(struct ib_device *device)
 	if (IS_ERR(sdev->cm_id)) {
 		pr_info("ib_create_cm_id() failed: %ld\n",
 			PTR_ERR(sdev->cm_id));
+		ret = PTR_ERR(sdev->cm_id);
 		sdev->cm_id = NULL;
 		if (!rdma_cm_id)
 			goto err_ring;
@@ -3179,7 +3182,8 @@ static void srpt_add_one(struct ib_device *device)
 		mutex_init(&sport->port_gid_id.mutex);
 		INIT_LIST_HEAD(&sport->port_gid_id.tpg_list);
 
-		if (srpt_refresh_port(sport)) {
+		ret = srpt_refresh_port(sport);
+		if (ret) {
 			pr_err("MAD registration failed for %s-%d.\n",
 			       dev_name(&sdev->device->dev), i);
 			goto err_event;
@@ -3190,10 +3194,9 @@ static void srpt_add_one(struct ib_device *device)
 	list_add_tail(&sdev->list, &srpt_dev_list);
 	spin_unlock(&srpt_dev_lock);
 
-out:
 	ib_set_client_data(device, &srpt_client, sdev);
 	pr_debug("added %s.\n", dev_name(&device->dev));
-	return;
+	return 0;
 
 err_event:
 	ib_unregister_event_handler(&sdev->event_handler);
@@ -3205,10 +3208,8 @@ err_ring:
 	ib_dealloc_pd(sdev->pd);
 free_dev:
 	kfree(sdev);
-err:
-	sdev = NULL;
 	pr_info("%s(%s) failed.\n", __func__, dev_name(&device->dev));
-	goto out;
+	return ret;
 }
 
 /**
@@ -3221,12 +3222,6 @@ static void srpt_remove_one(struct ib_device *device, void *client_data)
 	struct srpt_device *sdev = client_data;
 	int i;
 
-	if (!sdev) {
-		pr_info("%s(%s): nothing to do.\n", __func__,
-			dev_name(&device->dev));
-		return;
-	}
-
 	srpt_unregister_mad_agent(sdev);
 
 	ib_unregister_event_handler(&sdev->event_handler);