IB/uverbs: Build the specs into a radix tree at runtime

This radix tree datastructure is intended to replace the 'hash' structure
used today for parsing ioctl methods during system calls. This first
commit introduces the structure and builds it from the existing .rodata
descriptions.

The so-called hash arrangement is actually a 5 level open coded radix tree.
This new version uses a 3 level radix tree built using the radix tree
library.

Overall this is much less code and much easier to build as the radix tree
API allows for dynamic modification during the building. There is a small
memory penalty to pay for this, but since the radix tree is allocated on
a per device basis, a few kb of RAM seems immaterial considering the
gained simplicity.

The radix tree is similar to the existing tree, but also has a 'attr_bkey'
concept, which is a small value'd index for each method attribute. This is
used to simplify and improve performance of everything in the next
patches.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 20003594b5d6..0fab083cafef 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -174,6 +174,7 @@ static void ib_uverbs_release_dev(struct kobject *kobj)
 	struct ib_uverbs_device *dev =
 		container_of(kobj, struct ib_uverbs_device, kobj);
 
+	uverbs_destroy_api(dev->uapi);
 	cleanup_srcu_struct(&dev->disassociate_srcu);
 	uverbs_free_spec_tree(dev->specs_root);
 	kfree(dev);
@@ -1000,6 +1001,7 @@ static int ib_uverbs_create_uapi(struct ib_device *device,
 	const struct uverbs_object_tree_def **specs;
 	struct uverbs_root_spec *specs_root;
 	unsigned int num_specs = 1;
+	struct uverbs_api *uapi;
 	unsigned int i;
 
 	if (device->driver_specs)
@@ -1020,7 +1022,14 @@ static int ib_uverbs_create_uapi(struct ib_device *device,
 	if (IS_ERR(specs_root))
 		return PTR_ERR(specs_root);
 
+	uapi = uverbs_alloc_api(device->driver_specs, device->driver_id);
+	if (IS_ERR(uapi)) {
+		uverbs_free_spec_tree(specs_root);
+		return PTR_ERR(uapi);
+	}
+
 	uverbs_dev->specs_root = specs_root;
+	uverbs_dev->uapi = uapi;
 	return 0;
 }
 
@@ -1115,7 +1124,7 @@ static void ib_uverbs_free_hw_resources(struct ib_uverbs_device *uverbs_dev,
 	struct ib_event event;
 
 	/* Pending running commands to terminate */
-	synchronize_srcu(&uverbs_dev->disassociate_srcu);
+	uverbs_disassociate_api_pre(uverbs_dev);
 	event.event = IB_EVENT_DEVICE_FATAL;
 	event.element.port_num = 0;
 	event.device = ib_dev;
@@ -1161,6 +1170,8 @@ static void ib_uverbs_free_hw_resources(struct ib_uverbs_device *uverbs_dev,
 		kill_fasync(&event_file->ev_queue.async_queue, SIGIO, POLL_IN);
 	}
 	mutex_unlock(&uverbs_dev->lists_mutex);
+
+	uverbs_disassociate_api(uverbs_dev->uapi);
 }
 
 static void ib_uverbs_remove_one(struct ib_device *device, void *client_data)
@@ -1188,7 +1199,6 @@ static void ib_uverbs_remove_one(struct ib_device *device, void *client_data)
 		 * cdev was deleted, however active clients can still issue
 		 * commands and close their open files.
 		 */
-		rcu_assign_pointer(uverbs_dev->ib_dev, NULL);
 		ib_uverbs_free_hw_resources(uverbs_dev, device);
 		wait_clients = 0;
 	}