Commit e59178d8 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/devices: Use xarray to store the clients 



This gives each client a unique ID and will let us move client_data to use
xarray, and revise the locking scheme.

clients have to be add/removed in strict FIFO/LIFO order as they
interdepend. To support this the client_ids are assigned to increase in
FIFO order. The existing linked list is kept to support reverse iteration
until xarray can get a reverse iteration API.

Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: default avatarParav Pandit <parav@mellanox.com>
parent 3b88afd3

drivers/infiniband/core/device.c

+45 −5
Original line number Diff line number Diff line
@@ -65,15 +65,17 @@ struct workqueue_struct *ib_comp_unbound_wq; 
struct workqueue_struct *ib_wq;

EXPORT_SYMBOL_GPL(ib_wq);



/* The device_list and client_list contain devices and clients after their

/* The device_list and clients contain devices and clients after their

 * registration has completed, and the devices and clients are removed

 * during unregistration. */

static LIST_HEAD(device_list);

static LIST_HEAD(client_list);

#define CLIENT_REGISTERED XA_MARK_1

static DEFINE_XARRAY_FLAGS(clients, XA_FLAGS_ALLOC);



/*

 * device_mutex and lists_rwsem protect access to both device_list and

 * client_list.  device_mutex protects writer access by device and client

 * clients.  device_mutex protects writer access by device and client

 * registration / de-registration.  lists_rwsem protects reader access to

 * these lists.  Iterators of these lists must lock it for read, while updates

 * to the lists must be done with a write lock. A special case is when the
@@ -564,6 +566,7 @@ int ib_register_device(struct ib_device *device, const char *name) 
{

	int ret;

	struct ib_client *client;

	unsigned long index;



	setup_dma_device(device);
@@ -608,7 +611,7 @@ int ib_register_device(struct ib_device *device, const char *name) 


	refcount_set(&device->refcount, 1);



	list_for_each_entry(client, &client_list, list)

	xa_for_each_marked (&clients, index, client, CLIENT_REGISTERED)

		if (!add_client_context(device, client) && client->add)

			client->add(device);
@@ -680,6 +683,32 @@ void ib_unregister_device(struct ib_device *device) 
}

EXPORT_SYMBOL(ib_unregister_device);



static int assign_client_id(struct ib_client *client)

{

	int ret;



	/*

	 * The add/remove callbacks must be called in FIFO/LIFO order. To

	 * achieve this we assign client_ids so they are sorted in

	 * registration order, and retain a linked list we can reverse iterate

	 * to get the LIFO order. The extra linked list can go away if xarray

	 * learns to reverse iterate.

	 */

	if (list_empty(&client_list))

		client->client_id = 0;

	else

		client->client_id =

			list_last_entry(&client_list, struct ib_client, list)

				->client_id;

	ret = xa_alloc(&clients, &client->client_id, INT_MAX, client,

		       GFP_KERNEL);

	if (ret)

		goto out;



out:

	return ret;

}



/**

 * ib_register_client - Register an IB client

 * @client:Client to register
@@ -696,15 +725,21 @@ EXPORT_SYMBOL(ib_unregister_device); 
int ib_register_client(struct ib_client *client)

{

	struct ib_device *device;

	int ret;



	mutex_lock(&device_mutex);

	ret = assign_client_id(client);

	if (ret) {

		mutex_unlock(&device_mutex);

		return ret;

	}



	list_for_each_entry(device, &device_list, core_list)

		if (!add_client_context(device, client) && client->add)

			client->add(device);



	down_write(&lists_rwsem);

	list_add_tail(&client->list, &client_list);

	xa_set_mark(&clients, client->client_id, CLIENT_REGISTERED);

	up_write(&lists_rwsem);



	mutex_unlock(&device_mutex);
@@ -729,7 +764,7 @@ void ib_unregister_client(struct ib_client *client) 
	mutex_lock(&device_mutex);



	down_write(&lists_rwsem);

	list_del(&client->list);

	xa_clear_mark(&clients, client->client_id, CLIENT_REGISTERED);

	up_write(&lists_rwsem);



	list_for_each_entry(device, &device_list, core_list) {
@@ -765,6 +800,10 @@ void ib_unregister_client(struct ib_client *client) 
		kfree(found_context);

	}



	down_write(&lists_rwsem);

	list_del(&client->list);

	xa_erase(&clients, client->client_id);

	up_write(&lists_rwsem);

	mutex_unlock(&device_mutex);

}

EXPORT_SYMBOL(ib_unregister_client);
@@ -1422,6 +1461,7 @@ static void __exit ib_core_cleanup(void) 
	destroy_workqueue(ib_comp_wq);

	/* Make sure that any pending umem accounting work is done. */

	destroy_workqueue(ib_wq);

	WARN_ON(!xa_empty(&clients));

}



MODULE_ALIAS_RDMA_NETLINK(RDMA_NL_LS, 4);

include/rdma/ib_verbs.h

+2 −1
Original line number Diff line number Diff line
@@ -2610,7 +2610,7 @@ struct ib_device { 
};



struct ib_client {

	char  *name;

	const char *name;

	void (*add)   (struct ib_device *);

	void (*remove)(struct ib_device *, void *client_data);
@@ -2637,6 +2637,7 @@ struct ib_client { 
			const struct sockaddr *addr,

			void *client_data);

	struct list_head list;

	u32 client_id;



	/* kverbs are not required by the client */

	u8 no_kverbs_req:1;

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