/*
   * 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/slab.h>

  #include <linux/rculist.h>

  #include <linux/llist.h>

  
  #include "rds.h"

  #include "ib.h"

  static DEFINE_PER_CPU(unsigned long, clean_list_grace);
  #define CLEAN_LIST_BUSY_BIT 0

  
  /*
   * This is stored as mr->r_trans_private.
   */
  struct rds_ib_mr {
  	struct rds_ib_device	*device;
  	struct rds_ib_mr_pool	*pool;
  	struct ib_fmr		*fmr;

  	struct llist_node	llnode;

  
  	/* unmap_list is for freeing */
  	struct list_head	unmap_list;

  	unsigned int		remap_count;
  
  	struct scatterlist	*sg;
  	unsigned int		sg_len;
  	u64			*dma;
  	int			sg_dma_len;
  };
  
  /*
   * Our own little FMR pool
   */
  struct rds_ib_mr_pool {
  	struct mutex		flush_lock;		/* serialize fmr invalidate */

  	struct delayed_work	flush_worker;		/* flush worker */

  	atomic_t		item_count;		/* total # of MRs */
  	atomic_t		dirty_count;		/* # dirty of MRs */

  	struct llist_head	drop_list;		/* MRs that have reached their max_maps limit */
  	struct llist_head	free_list;		/* unused MRs */
  	struct llist_head	clean_list;		/* global unused & unamapped MRs */

  	wait_queue_head_t	flush_wait;

  	atomic_t		free_pinned;		/* memory pinned by free MRs */
  	unsigned long		max_items;
  	unsigned long		max_items_soft;
  	unsigned long		max_free_pinned;
  	struct ib_fmr_attr	fmr_attr;
  };

  static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all, struct rds_ib_mr **);

  static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr);
  static void rds_ib_mr_pool_flush_worker(struct work_struct *work);
  
  static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
  {
  	struct rds_ib_device *rds_ibdev;
  	struct rds_ib_ipaddr *i_ipaddr;

  	rcu_read_lock();
  	list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) {

  		list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {

  			if (i_ipaddr->ipaddr == ipaddr) {

  				atomic_inc(&rds_ibdev->refcount);

  				rcu_read_unlock();

  				return rds_ibdev;
  			}
  		}

  	}

  	rcu_read_unlock();

  
  	return NULL;
  }
  
  static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
  {
  	struct rds_ib_ipaddr *i_ipaddr;
  
  	i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
  	if (!i_ipaddr)
  		return -ENOMEM;
  
  	i_ipaddr->ipaddr = ipaddr;
  
  	spin_lock_irq(&rds_ibdev->spinlock);

  	list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);

  	spin_unlock_irq(&rds_ibdev->spinlock);
  
  	return 0;
  }
  
  static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
  {

  	struct rds_ib_ipaddr *i_ipaddr;

  	struct rds_ib_ipaddr *to_free = NULL;

  
  	spin_lock_irq(&rds_ibdev->spinlock);

  	list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {

  		if (i_ipaddr->ipaddr == ipaddr) {

  			list_del_rcu(&i_ipaddr->list);
  			to_free = i_ipaddr;

  			break;
  		}
  	}
  	spin_unlock_irq(&rds_ibdev->spinlock);

  
  	if (to_free) {
  		synchronize_rcu();
  		kfree(to_free);
  	}

  }
  
  int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
  {
  	struct rds_ib_device *rds_ibdev_old;
  
  	rds_ibdev_old = rds_ib_get_device(ipaddr);

  	if (rds_ibdev_old) {

  		rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);

  		rds_ib_dev_put(rds_ibdev_old);
  	}

  
  	return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
  }

  void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)

  {
  	struct rds_ib_connection *ic = conn->c_transport_data;
  
  	/* conn was previously on the nodev_conns_list */
  	spin_lock_irq(&ib_nodev_conns_lock);
  	BUG_ON(list_empty(&ib_nodev_conns));
  	BUG_ON(list_empty(&ic->ib_node));
  	list_del(&ic->ib_node);

  	spin_lock(&rds_ibdev->spinlock);

  	list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);

  	spin_unlock(&rds_ibdev->spinlock);

  	spin_unlock_irq(&ib_nodev_conns_lock);

  
  	ic->rds_ibdev = rds_ibdev;

  	atomic_inc(&rds_ibdev->refcount);

  }

  void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)

  {

  	struct rds_ib_connection *ic = conn->c_transport_data;

  	/* place conn on nodev_conns_list */
  	spin_lock(&ib_nodev_conns_lock);

  	spin_lock_irq(&rds_ibdev->spinlock);
  	BUG_ON(list_empty(&ic->ib_node));
  	list_del(&ic->ib_node);
  	spin_unlock_irq(&rds_ibdev->spinlock);
  
  	list_add_tail(&ic->ib_node, &ib_nodev_conns);
  
  	spin_unlock(&ib_nodev_conns_lock);
  
  	ic->rds_ibdev = NULL;

  	rds_ib_dev_put(rds_ibdev);

  }

  void rds_ib_destroy_nodev_conns(void)

  {
  	struct rds_ib_connection *ic, *_ic;
  	LIST_HEAD(tmp_list);
  
  	/* avoid calling conn_destroy with irqs off */

  	spin_lock_irq(&ib_nodev_conns_lock);
  	list_splice(&ib_nodev_conns, &tmp_list);
  	spin_unlock_irq(&ib_nodev_conns_lock);

  	list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)

  		rds_conn_destroy(ic->conn);

  }
  
  struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
  {
  	struct rds_ib_mr_pool *pool;
  
  	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
  	if (!pool)
  		return ERR_PTR(-ENOMEM);

  	init_llist_head(&pool->free_list);
  	init_llist_head(&pool->drop_list);
  	init_llist_head(&pool->clean_list);

  	mutex_init(&pool->flush_lock);

  	init_waitqueue_head(&pool->flush_wait);

  	INIT_DELAYED_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);

  
  	pool->fmr_attr.max_pages = fmr_message_size;
  	pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;

  	pool->fmr_attr.page_shift = PAGE_SHIFT;

  	pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
  
  	/* We never allow more than max_items MRs to be allocated.
  	 * When we exceed more than max_items_soft, we start freeing
  	 * items more aggressively.
  	 * Make sure that max_items > max_items_soft > max_items / 2
  	 */
  	pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
  	pool->max_items = rds_ibdev->max_fmrs;
  
  	return pool;
  }
  
  void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
  {
  	struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
  
  	iinfo->rdma_mr_max = pool->max_items;
  	iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
  }
  
  void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
  {

  	cancel_delayed_work_sync(&pool->flush_worker);

  	rds_ib_flush_mr_pool(pool, 1, NULL);

  	WARN_ON(atomic_read(&pool->item_count));
  	WARN_ON(atomic_read(&pool->free_pinned));

  	kfree(pool);
  }
  
  static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
  {
  	struct rds_ib_mr *ibmr = NULL;

  	struct llist_node *ret;

  	unsigned long *flag;

  	preempt_disable();
  	flag = &__get_cpu_var(clean_list_grace);
  	set_bit(CLEAN_LIST_BUSY_BIT, flag);

  	ret = llist_del_first(&pool->clean_list);

  	if (ret)

  		ibmr = llist_entry(ret, struct rds_ib_mr, llnode);

  	clear_bit(CLEAN_LIST_BUSY_BIT, flag);
  	preempt_enable();

  	return ibmr;
  }

  static inline void wait_clean_list_grace(void)
  {
  	int cpu;
  	unsigned long *flag;
  
  	for_each_online_cpu(cpu) {
  		flag = &per_cpu(clean_list_grace, cpu);
  		while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
  			cpu_relax();
  	}
  }

  static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
  {
  	struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
  	struct rds_ib_mr *ibmr = NULL;
  	int err = 0, iter = 0;

  	if (atomic_read(&pool->dirty_count) >= pool->max_items / 10)

  		schedule_delayed_work(&pool->flush_worker, 10);

  	while (1) {
  		ibmr = rds_ib_reuse_fmr(pool);
  		if (ibmr)
  			return ibmr;
  
  		/* No clean MRs - now we have the choice of either
  		 * allocating a fresh MR up to the limit imposed by the
  		 * driver, or flush any dirty unused MRs.
  		 * We try to avoid stalling in the send path if possible,
  		 * so we allocate as long as we're allowed to.
  		 *
  		 * We're fussy with enforcing the FMR limit, though. If the driver
  		 * tells us we can't use more than N fmrs, we shouldn't start
  		 * arguing with it */
  		if (atomic_inc_return(&pool->item_count) <= pool->max_items)
  			break;
  
  		atomic_dec(&pool->item_count);
  
  		if (++iter > 2) {
  			rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
  			return ERR_PTR(-EAGAIN);
  		}
  
  		/* We do have some empty MRs. Flush them out. */
  		rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);

  		rds_ib_flush_mr_pool(pool, 0, &ibmr);
  		if (ibmr)
  			return ibmr;

  	}

  	ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL, rdsibdev_to_node(rds_ibdev));

  	if (!ibmr) {
  		err = -ENOMEM;
  		goto out_no_cigar;
  	}

  	memset(ibmr, 0, sizeof(*ibmr));

  	ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
  			(IB_ACCESS_LOCAL_WRITE |
  			 IB_ACCESS_REMOTE_READ |

  			 IB_ACCESS_REMOTE_WRITE|
  			 IB_ACCESS_REMOTE_ATOMIC),

  			&pool->fmr_attr);
  	if (IS_ERR(ibmr->fmr)) {
  		err = PTR_ERR(ibmr->fmr);
  		ibmr->fmr = NULL;
  		printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)
  ", err);
  		goto out_no_cigar;
  	}
  
  	rds_ib_stats_inc(s_ib_rdma_mr_alloc);
  	return ibmr;
  
  out_no_cigar:
  	if (ibmr) {
  		if (ibmr->fmr)
  			ib_dealloc_fmr(ibmr->fmr);
  		kfree(ibmr);
  	}
  	atomic_dec(&pool->item_count);
  	return ERR_PTR(err);
  }
  
  static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
  	       struct scatterlist *sg, unsigned int nents)
  {
  	struct ib_device *dev = rds_ibdev->dev;
  	struct scatterlist *scat = sg;
  	u64 io_addr = 0;
  	u64 *dma_pages;
  	u32 len;
  	int page_cnt, sg_dma_len;
  	int i, j;
  	int ret;
  
  	sg_dma_len = ib_dma_map_sg(dev, sg, nents,
  				 DMA_BIDIRECTIONAL);
  	if (unlikely(!sg_dma_len)) {
  		printk(KERN_WARNING "RDS/IB: dma_map_sg failed!
  ");
  		return -EBUSY;
  	}
  
  	len = 0;
  	page_cnt = 0;
  
  	for (i = 0; i < sg_dma_len; ++i) {
  		unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
  		u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);

  		if (dma_addr & ~PAGE_MASK) {

  			if (i > 0)
  				return -EINVAL;
  			else
  				++page_cnt;
  		}

  		if ((dma_addr + dma_len) & ~PAGE_MASK) {

  			if (i < sg_dma_len - 1)
  				return -EINVAL;
  			else
  				++page_cnt;
  		}
  
  		len += dma_len;
  	}

  	page_cnt += len >> PAGE_SHIFT;

  	if (page_cnt > fmr_message_size)
  		return -EINVAL;

  	dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
  				 rdsibdev_to_node(rds_ibdev));

  	if (!dma_pages)
  		return -ENOMEM;
  
  	page_cnt = 0;
  	for (i = 0; i < sg_dma_len; ++i) {
  		unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
  		u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);

  		for (j = 0; j < dma_len; j += PAGE_SIZE)

  			dma_pages[page_cnt++] =

  				(dma_addr & PAGE_MASK) + j;

  	}
  
  	ret = ib_map_phys_fmr(ibmr->fmr,
  				   dma_pages, page_cnt, io_addr);
  	if (ret)
  		goto out;
  
  	/* Success - we successfully remapped the MR, so we can
  	 * safely tear down the old mapping. */
  	rds_ib_teardown_mr(ibmr);
  
  	ibmr->sg = scat;
  	ibmr->sg_len = nents;
  	ibmr->sg_dma_len = sg_dma_len;
  	ibmr->remap_count++;
  
  	rds_ib_stats_inc(s_ib_rdma_mr_used);
  	ret = 0;
  
  out:
  	kfree(dma_pages);
  
  	return ret;
  }
  
  void rds_ib_sync_mr(void *trans_private, int direction)
  {
  	struct rds_ib_mr *ibmr = trans_private;
  	struct rds_ib_device *rds_ibdev = ibmr->device;
  
  	switch (direction) {
  	case DMA_FROM_DEVICE:
  		ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
  			ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
  		break;
  	case DMA_TO_DEVICE:
  		ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
  			ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
  		break;
  	}
  }
  
  static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
  {
  	struct rds_ib_device *rds_ibdev = ibmr->device;
  
  	if (ibmr->sg_dma_len) {
  		ib_dma_unmap_sg(rds_ibdev->dev,
  				ibmr->sg, ibmr->sg_len,
  				DMA_BIDIRECTIONAL);
  		ibmr->sg_dma_len = 0;
  	}
  
  	/* Release the s/g list */
  	if (ibmr->sg_len) {
  		unsigned int i;
  
  		for (i = 0; i < ibmr->sg_len; ++i) {
  			struct page *page = sg_page(&ibmr->sg[i]);
  
  			/* FIXME we need a way to tell a r/w MR
  			 * from a r/o MR */

  			BUG_ON(irqs_disabled());

  			set_page_dirty(page);
  			put_page(page);
  		}
  		kfree(ibmr->sg);
  
  		ibmr->sg = NULL;
  		ibmr->sg_len = 0;
  	}
  }
  
  static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
  {
  	unsigned int pinned = ibmr->sg_len;
  
  	__rds_ib_teardown_mr(ibmr);
  	if (pinned) {
  		struct rds_ib_device *rds_ibdev = ibmr->device;
  		struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
  
  		atomic_sub(pinned, &pool->free_pinned);
  	}
  }
  
  static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
  {
  	unsigned int item_count;
  
  	item_count = atomic_read(&pool->item_count);
  	if (free_all)
  		return item_count;
  
  	return 0;
  }
  
  /*

   * given an llist of mrs, put them all into the list_head for more processing

   */

  static void llist_append_to_list(struct llist_head *llist, struct list_head *list)

  {
  	struct rds_ib_mr *ibmr;

  	struct llist_node *node;
  	struct llist_node *next;
  
  	node = llist_del_all(llist);
  	while (node) {
  		next = node->next;
  		ibmr = llist_entry(node, struct rds_ib_mr, llnode);

  		list_add_tail(&ibmr->unmap_list, list);

  		node = next;

  	}
  }
  
  /*

   * this takes a list head of mrs and turns it into linked llist nodes
   * of clusters.  Each cluster has linked llist nodes of
   * MR_CLUSTER_SIZE mrs that are ready for reuse.

   */

  static void list_to_llist_nodes(struct rds_ib_mr_pool *pool,
  				struct list_head *list,
  				struct llist_node **nodes_head,
  				struct llist_node **nodes_tail)

  {
  	struct rds_ib_mr *ibmr;

  	struct llist_node *cur = NULL;
  	struct llist_node **next = nodes_head;

  
  	list_for_each_entry(ibmr, list, unmap_list) {

  		cur = &ibmr->llnode;
  		*next = cur;
  		next = &cur->next;

  	}

  	*next = NULL;
  	*nodes_tail = cur;

  }
  
  /*

   * Flush our pool of MRs.
   * At a minimum, all currently unused MRs are unmapped.
   * If the number of MRs allocated exceeds the limit, we also try
   * to free as many MRs as needed to get back to this limit.
   */

  static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool,
  			        int free_all, struct rds_ib_mr **ibmr_ret)

  {
  	struct rds_ib_mr *ibmr, *next;

  	struct llist_node *clean_nodes;
  	struct llist_node *clean_tail;

  	LIST_HEAD(unmap_list);
  	LIST_HEAD(fmr_list);
  	unsigned long unpinned = 0;

  	unsigned int nfreed = 0, ncleaned = 0, free_goal;
  	int ret = 0;
  
  	rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);

  	if (ibmr_ret) {
  		DEFINE_WAIT(wait);
  		while(!mutex_trylock(&pool->flush_lock)) {
  			ibmr = rds_ib_reuse_fmr(pool);
  			if (ibmr) {
  				*ibmr_ret = ibmr;
  				finish_wait(&pool->flush_wait, &wait);
  				goto out_nolock;
  			}
  
  			prepare_to_wait(&pool->flush_wait, &wait,
  					TASK_UNINTERRUPTIBLE);

  			if (llist_empty(&pool->clean_list))

  				schedule();
  
  			ibmr = rds_ib_reuse_fmr(pool);
  			if (ibmr) {
  				*ibmr_ret = ibmr;
  				finish_wait(&pool->flush_wait, &wait);
  				goto out_nolock;
  			}
  		}
  		finish_wait(&pool->flush_wait, &wait);
  	} else
  		mutex_lock(&pool->flush_lock);
  
  	if (ibmr_ret) {
  		ibmr = rds_ib_reuse_fmr(pool);
  		if (ibmr) {
  			*ibmr_ret = ibmr;
  			goto out;
  		}
  	}

  	/* Get the list of all MRs to be dropped. Ordering matters -

  	 * we want to put drop_list ahead of free_list.
  	 */

  	llist_append_to_list(&pool->drop_list, &unmap_list);
  	llist_append_to_list(&pool->free_list, &unmap_list);

  	if (free_all)

  		llist_append_to_list(&pool->clean_list, &unmap_list);

  
  	free_goal = rds_ib_flush_goal(pool, free_all);
  
  	if (list_empty(&unmap_list))
  		goto out;
  
  	/* String all ib_mr's onto one list and hand them to ib_unmap_fmr */

  	list_for_each_entry(ibmr, &unmap_list, unmap_list)

  		list_add(&ibmr->fmr->list, &fmr_list);

  	ret = ib_unmap_fmr(&fmr_list);
  	if (ret)
  		printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)
  ", ret);
  
  	/* Now we can destroy the DMA mapping and unpin any pages */

  	list_for_each_entry_safe(ibmr, next, &unmap_list, unmap_list) {

  		unpinned += ibmr->sg_len;
  		__rds_ib_teardown_mr(ibmr);
  		if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
  			rds_ib_stats_inc(s_ib_rdma_mr_free);

  			list_del(&ibmr->unmap_list);

  			ib_dealloc_fmr(ibmr->fmr);
  			kfree(ibmr);
  			nfreed++;
  		}
  		ncleaned++;
  	}

  	if (!list_empty(&unmap_list)) {
  		/* we have to make sure that none of the things we're about
  		 * to put on the clean list would race with other cpus trying

  		 * to pull items off.  The llist would explode if we managed to

  		 * remove something from the clean list and then add it back again

  		 * while another CPU was spinning on that same item in llist_del_first.

  		 *

  		 * This is pretty unlikely, but just in case  wait for an llist grace period

  		 * here before adding anything back into the clean list.
  		 */
  		wait_clean_list_grace();

  		list_to_llist_nodes(pool, &unmap_list, &clean_nodes, &clean_tail);

  		if (ibmr_ret)

  			*ibmr_ret = llist_entry(clean_nodes, struct rds_ib_mr, llnode);

  		/* more than one entry in llist nodes */
  		if (clean_nodes->next)
  			llist_add_batch(clean_nodes->next, clean_tail, &pool->clean_list);

  
  	}

  
  	atomic_sub(unpinned, &pool->free_pinned);
  	atomic_sub(ncleaned, &pool->dirty_count);
  	atomic_sub(nfreed, &pool->item_count);
  
  out:
  	mutex_unlock(&pool->flush_lock);

  	if (waitqueue_active(&pool->flush_wait))
  		wake_up(&pool->flush_wait);
  out_nolock:

  	return ret;
  }
  
  static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
  {

  	struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);

  	rds_ib_flush_mr_pool(pool, 0, NULL);

  }
  
  void rds_ib_free_mr(void *trans_private, int invalidate)
  {
  	struct rds_ib_mr *ibmr = trans_private;
  	struct rds_ib_device *rds_ibdev = ibmr->device;
  	struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;

  
  	rdsdebug("RDS/IB: free_mr nents %u
  ", ibmr->sg_len);
  
  	/* Return it to the pool's free list */

  	if (ibmr->remap_count >= pool->fmr_attr.max_maps)

  		llist_add(&ibmr->llnode, &pool->drop_list);

  	else

  		llist_add(&ibmr->llnode, &pool->free_list);

  
  	atomic_add(ibmr->sg_len, &pool->free_pinned);
  	atomic_inc(&pool->dirty_count);

  
  	/* If we've pinned too many pages, request a flush */

  	if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
  	    atomic_read(&pool->dirty_count) >= pool->max_items / 10)

  		schedule_delayed_work(&pool->flush_worker, 10);

  
  	if (invalidate) {
  		if (likely(!in_interrupt())) {

  			rds_ib_flush_mr_pool(pool, 0, NULL);

  		} else {
  			/* We get here if the user created a MR marked
  			 * as use_once and invalidate at the same time. */

  			schedule_delayed_work(&pool->flush_worker, 10);

  		}
  	}

  
  	rds_ib_dev_put(rds_ibdev);

  }
  
  void rds_ib_flush_mrs(void)
  {
  	struct rds_ib_device *rds_ibdev;

  	down_read(&rds_ib_devices_lock);

  	list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
  		struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
  
  		if (pool)

  			rds_ib_flush_mr_pool(pool, 0, NULL);

  	}

  	up_read(&rds_ib_devices_lock);

  }
  
  void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
  		    struct rds_sock *rs, u32 *key_ret)
  {
  	struct rds_ib_device *rds_ibdev;
  	struct rds_ib_mr *ibmr = NULL;
  	int ret;
  
  	rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
  	if (!rds_ibdev) {
  		ret = -ENODEV;
  		goto out;
  	}
  
  	if (!rds_ibdev->mr_pool) {
  		ret = -ENODEV;
  		goto out;
  	}
  
  	ibmr = rds_ib_alloc_fmr(rds_ibdev);
  	if (IS_ERR(ibmr))
  		return ibmr;
  
  	ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
  	if (ret == 0)
  		*key_ret = ibmr->fmr->rkey;
  	else
  		printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)
  ", ret);
  
  	ibmr->device = rds_ibdev;

  	rds_ibdev = NULL;

  
   out:
  	if (ret) {
  		if (ibmr)
  			rds_ib_free_mr(ibmr, 0);
  		ibmr = ERR_PTR(ret);
  	}

  	if (rds_ibdev)
  		rds_ib_dev_put(rds_ibdev);

  	return ibmr;
  }