/*
   * Copyright (c) 2006 Oracle.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  #include <linux/kernel.h>
  #include <linux/in.h>
  #include <linux/if.h>
  #include <linux/netdevice.h>
  #include <linux/inetdevice.h>
  #include <linux/if_arp.h>
  #include <linux/delay.h>

  #include <linux/slab.h>

  #include <linux/module.h>

  
  #include "rds.h"
  #include "ib.h"

  static unsigned int fmr_pool_size = RDS_FMR_POOL_SIZE;

  unsigned int fmr_message_size = RDS_FMR_SIZE + 1; /* +1 allows for unaligned MRs */

  unsigned int rds_ib_retry_count = RDS_IB_DEFAULT_RETRY_COUNT;

  
  module_param(fmr_pool_size, int, 0444);
  MODULE_PARM_DESC(fmr_pool_size, " Max number of fmr per HCA");
  module_param(fmr_message_size, int, 0444);
  MODULE_PARM_DESC(fmr_message_size, " Max size of a RDMA transfer");

  module_param(rds_ib_retry_count, int, 0444);
  MODULE_PARM_DESC(rds_ib_retry_count, " Number of hw retries before reporting an error");

  /*
   * we have a clumsy combination of RCU and a rwsem protecting this list
   * because it is used both in the get_mr fast path and while blocking in
   * the FMR flushing path.
   */
  DECLARE_RWSEM(rds_ib_devices_lock);

  struct list_head rds_ib_devices;

  /* NOTE: if also grabbing ibdev lock, grab this first */

  DEFINE_SPINLOCK(ib_nodev_conns_lock);
  LIST_HEAD(ib_nodev_conns);

  static void rds_ib_nodev_connect(void)

  {
  	struct rds_ib_connection *ic;
  
  	spin_lock(&ib_nodev_conns_lock);
  	list_for_each_entry(ic, &ib_nodev_conns, ib_node)
  		rds_conn_connect_if_down(ic->conn);
  	spin_unlock(&ib_nodev_conns_lock);
  }

  static void rds_ib_dev_shutdown(struct rds_ib_device *rds_ibdev)

  {
  	struct rds_ib_connection *ic;
  	unsigned long flags;
  
  	spin_lock_irqsave(&rds_ibdev->spinlock, flags);
  	list_for_each_entry(ic, &rds_ibdev->conn_list, ib_node)
  		rds_conn_drop(ic->conn);
  	spin_unlock_irqrestore(&rds_ibdev->spinlock, flags);
  }

  /*
   * rds_ib_destroy_mr_pool() blocks on a few things and mrs drop references
   * from interrupt context so we push freing off into a work struct in krdsd.
   */
  static void rds_ib_dev_free(struct work_struct *work)
  {
  	struct rds_ib_ipaddr *i_ipaddr, *i_next;
  	struct rds_ib_device *rds_ibdev = container_of(work,
  					struct rds_ib_device, free_work);
  
  	if (rds_ibdev->mr_pool)
  		rds_ib_destroy_mr_pool(rds_ibdev->mr_pool);
  	if (rds_ibdev->mr)
  		ib_dereg_mr(rds_ibdev->mr);
  	if (rds_ibdev->pd)
  		ib_dealloc_pd(rds_ibdev->pd);
  
  	list_for_each_entry_safe(i_ipaddr, i_next, &rds_ibdev->ipaddr_list, list) {
  		list_del(&i_ipaddr->list);
  		kfree(i_ipaddr);
  	}
  
  	kfree(rds_ibdev);
  }
  
  void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
  {
  	BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0);
  	if (atomic_dec_and_test(&rds_ibdev->refcount))
  		queue_work(rds_wq, &rds_ibdev->free_work);
  }

  static void rds_ib_add_one(struct ib_device *device)

  {
  	struct rds_ib_device *rds_ibdev;
  	struct ib_device_attr *dev_attr;
  
  	/* Only handle IB (no iWARP) devices */
  	if (device->node_type != RDMA_NODE_IB_CA)
  		return;
  
  	dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
  	if (!dev_attr)
  		return;
  
  	if (ib_query_device(device, dev_attr)) {
  		rdsdebug("Query device failed for %s
  ", device->name);
  		goto free_attr;
  	}

  	rds_ibdev = kzalloc_node(sizeof(struct rds_ib_device), GFP_KERNEL,
  				 ibdev_to_node(device));

  	if (!rds_ibdev)
  		goto free_attr;
  
  	spin_lock_init(&rds_ibdev->spinlock);

  	atomic_set(&rds_ibdev->refcount, 1);
  	INIT_WORK(&rds_ibdev->free_work, rds_ib_dev_free);

  
  	rds_ibdev->max_wrs = dev_attr->max_qp_wr;
  	rds_ibdev->max_sge = min(dev_attr->max_sge, RDS_IB_MAX_SGE);

  	rds_ibdev->fmr_max_remaps = dev_attr->max_map_per_fmr?: 32;
  	rds_ibdev->max_fmrs = dev_attr->max_fmr ?
  			min_t(unsigned int, dev_attr->max_fmr, fmr_pool_size) :
  			fmr_pool_size;

  	rds_ibdev->max_initiator_depth = dev_attr->max_qp_init_rd_atom;
  	rds_ibdev->max_responder_resources = dev_attr->max_qp_rd_atom;

  	rds_ibdev->dev = device;
  	rds_ibdev->pd = ib_alloc_pd(device);

  	if (IS_ERR(rds_ibdev->pd)) {
  		rds_ibdev->pd = NULL;
  		goto put_dev;
  	}

  	rds_ibdev->mr = ib_get_dma_mr(rds_ibdev->pd, IB_ACCESS_LOCAL_WRITE);
  	if (IS_ERR(rds_ibdev->mr)) {
  		rds_ibdev->mr = NULL;
  		goto put_dev;
  	}

  
  	rds_ibdev->mr_pool = rds_ib_create_mr_pool(rds_ibdev);
  	if (IS_ERR(rds_ibdev->mr_pool)) {
  		rds_ibdev->mr_pool = NULL;

  		goto put_dev;

  	}
  
  	INIT_LIST_HEAD(&rds_ibdev->ipaddr_list);
  	INIT_LIST_HEAD(&rds_ibdev->conn_list);

  
  	down_write(&rds_ib_devices_lock);
  	list_add_tail_rcu(&rds_ibdev->list, &rds_ib_devices);
  	up_write(&rds_ib_devices_lock);

  	atomic_inc(&rds_ibdev->refcount);

  
  	ib_set_client_data(device, &rds_ib_client, rds_ibdev);

  	atomic_inc(&rds_ibdev->refcount);

  	rds_ib_nodev_connect();

  put_dev:
  	rds_ib_dev_put(rds_ibdev);

  free_attr:
  	kfree(dev_attr);
  }

  /*
   * New connections use this to find the device to associate with the
   * connection.  It's not in the fast path so we're not concerned about the
   * performance of the IB call.  (As of this writing, it uses an interrupt
   * blocking spinlock to serialize walking a per-device list of all registered
   * clients.)
   *
   * RCU is used to handle incoming connections racing with device teardown.
   * Rather than use a lock to serialize removal from the client_data and
   * getting a new reference, we use an RCU grace period.  The destruction
   * path removes the device from client_data and then waits for all RCU
   * readers to finish.
   *
   * A new connection can get NULL from this if its arriving on a
   * device that is in the process of being removed.
   */
  struct rds_ib_device *rds_ib_get_client_data(struct ib_device *device)
  {
  	struct rds_ib_device *rds_ibdev;
  
  	rcu_read_lock();
  	rds_ibdev = ib_get_client_data(device, &rds_ib_client);
  	if (rds_ibdev)
  		atomic_inc(&rds_ibdev->refcount);
  	rcu_read_unlock();
  	return rds_ibdev;
  }
  
  /*
   * The IB stack is letting us know that a device is going away.  This can
   * happen if the underlying HCA driver is removed or if PCI hotplug is removing
   * the pci function, for example.
   *
   * This can be called at any time and can be racing with any other RDS path.
   */

  static void rds_ib_remove_one(struct ib_device *device)

  {
  	struct rds_ib_device *rds_ibdev;

  
  	rds_ibdev = ib_get_client_data(device, &rds_ib_client);
  	if (!rds_ibdev)
  		return;

  	rds_ib_dev_shutdown(rds_ibdev);

  	/* stop connection attempts from getting a reference to this device. */
  	ib_set_client_data(device, &rds_ib_client, NULL);
  
  	down_write(&rds_ib_devices_lock);
  	list_del_rcu(&rds_ibdev->list);
  	up_write(&rds_ib_devices_lock);

  	/*

  	 * This synchronize rcu is waiting for readers of both the ib
  	 * client data and the devices list to finish before we drop
  	 * both of those references.

  	 */

  	synchronize_rcu();
  	rds_ib_dev_put(rds_ibdev);

  	rds_ib_dev_put(rds_ibdev);

  }
  
  struct ib_client rds_ib_client = {
  	.name   = "rds_ib",
  	.add    = rds_ib_add_one,
  	.remove = rds_ib_remove_one
  };
  
  static int rds_ib_conn_info_visitor(struct rds_connection *conn,
  				    void *buffer)
  {
  	struct rds_info_rdma_connection *iinfo = buffer;
  	struct rds_ib_connection *ic;
  
  	/* We will only ever look at IB transports */
  	if (conn->c_trans != &rds_ib_transport)
  		return 0;
  
  	iinfo->src_addr = conn->c_laddr;
  	iinfo->dst_addr = conn->c_faddr;
  
  	memset(&iinfo->src_gid, 0, sizeof(iinfo->src_gid));
  	memset(&iinfo->dst_gid, 0, sizeof(iinfo->dst_gid));
  	if (rds_conn_state(conn) == RDS_CONN_UP) {
  		struct rds_ib_device *rds_ibdev;
  		struct rdma_dev_addr *dev_addr;
  
  		ic = conn->c_transport_data;
  		dev_addr = &ic->i_cm_id->route.addr.dev_addr;

  		rdma_addr_get_sgid(dev_addr, (union ib_gid *) &iinfo->src_gid);
  		rdma_addr_get_dgid(dev_addr, (union ib_gid *) &iinfo->dst_gid);

  		rds_ibdev = ic->rds_ibdev;

  		iinfo->max_send_wr = ic->i_send_ring.w_nr;
  		iinfo->max_recv_wr = ic->i_recv_ring.w_nr;
  		iinfo->max_send_sge = rds_ibdev->max_sge;
  		rds_ib_get_mr_info(rds_ibdev, iinfo);
  	}
  	return 1;
  }
  
  static void rds_ib_ic_info(struct socket *sock, unsigned int len,
  			   struct rds_info_iterator *iter,
  			   struct rds_info_lengths *lens)
  {
  	rds_for_each_conn_info(sock, len, iter, lens,
  				rds_ib_conn_info_visitor,
  				sizeof(struct rds_info_rdma_connection));
  }
  
  
  /*
   * Early RDS/IB was built to only bind to an address if there is an IPoIB
   * device with that address set.
   *
   * If it were me, I'd advocate for something more flexible.  Sending and
   * receiving should be device-agnostic.  Transports would try and maintain
   * connections between peers who have messages queued.  Userspace would be
   * allowed to influence which paths have priority.  We could call userspace
   * asserting this policy "routing".
   */
  static int rds_ib_laddr_check(__be32 addr)
  {
  	int ret;
  	struct rdma_cm_id *cm_id;
  	struct sockaddr_in sin;
  
  	/* Create a CMA ID and try to bind it. This catches both
  	 * IB and iWARP capable NICs.
  	 */

  	cm_id = rdma_create_id(NULL, NULL, RDMA_PS_TCP, IB_QPT_RC);

  	if (IS_ERR(cm_id))
  		return PTR_ERR(cm_id);

  
  	memset(&sin, 0, sizeof(sin));
  	sin.sin_family = AF_INET;
  	sin.sin_addr.s_addr = addr;
  
  	/* rdma_bind_addr will only succeed for IB & iWARP devices */
  	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin);
  	/* due to this, we will claim to support iWARP devices unless we
  	   check node_type. */
  	if (ret || cm_id->device->node_type != RDMA_NODE_IB_CA)
  		ret = -EADDRNOTAVAIL;
  
  	rdsdebug("addr %pI4 ret %d node type %d
  ",
  		&addr, ret,
  		cm_id->device ? cm_id->device->node_type : -1);
  
  	rdma_destroy_id(cm_id);
  
  	return ret;
  }

  static void rds_ib_unregister_client(void)
  {
  	ib_unregister_client(&rds_ib_client);
  	/* wait for rds_ib_dev_free() to complete */
  	flush_workqueue(rds_wq);
  }

  void rds_ib_exit(void)
  {
  	rds_info_deregister_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);

  	rds_ib_unregister_client();

  	rds_ib_destroy_nodev_conns();

  	rds_ib_sysctl_exit();
  	rds_ib_recv_exit();
  	rds_trans_unregister(&rds_ib_transport);
  }
  
  struct rds_transport rds_ib_transport = {
  	.laddr_check		= rds_ib_laddr_check,
  	.xmit_complete		= rds_ib_xmit_complete,
  	.xmit			= rds_ib_xmit,

  	.xmit_rdma		= rds_ib_xmit_rdma,

  	.xmit_atomic		= rds_ib_xmit_atomic,

  	.recv			= rds_ib_recv,
  	.conn_alloc		= rds_ib_conn_alloc,
  	.conn_free		= rds_ib_conn_free,
  	.conn_connect		= rds_ib_conn_connect,
  	.conn_shutdown		= rds_ib_conn_shutdown,
  	.inc_copy_to_user	= rds_ib_inc_copy_to_user,

  	.inc_free		= rds_ib_inc_free,
  	.cm_initiate_connect	= rds_ib_cm_initiate_connect,
  	.cm_handle_connect	= rds_ib_cm_handle_connect,
  	.cm_connect_complete	= rds_ib_cm_connect_complete,
  	.stats_info_copy	= rds_ib_stats_info_copy,
  	.exit			= rds_ib_exit,
  	.get_mr			= rds_ib_get_mr,
  	.sync_mr		= rds_ib_sync_mr,
  	.free_mr		= rds_ib_free_mr,
  	.flush_mrs		= rds_ib_flush_mrs,
  	.t_owner		= THIS_MODULE,
  	.t_name			= "infiniband",

  	.t_type			= RDS_TRANS_IB

  };

  int rds_ib_init(void)

  {
  	int ret;
  
  	INIT_LIST_HEAD(&rds_ib_devices);

  	ret = ib_register_client(&rds_ib_client);
  	if (ret)

  		goto out;

  	ret = rds_ib_sysctl_init();
  	if (ret)
  		goto out_ibreg;
  
  	ret = rds_ib_recv_init();
  	if (ret)
  		goto out_sysctl;
  
  	ret = rds_trans_register(&rds_ib_transport);
  	if (ret)
  		goto out_recv;
  
  	rds_info_register_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);
  
  	goto out;
  
  out_recv:
  	rds_ib_recv_exit();
  out_sysctl:
  	rds_ib_sysctl_exit();
  out_ibreg:

  	rds_ib_unregister_client();

  out:
  	return ret;
  }
  
  MODULE_LICENSE("GPL");