net/rds/ib_rdma.c - third_party/linux - Git at Google

 /*
  * 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_single_path.h"
 #include "ib_mr.h"

 struct workqueue_struct *rds_ib_mr_wq;

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

 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) {
 				refcount_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)
 		kfree_rcu(to_free, rcu);
 }

 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)
 		return rds_ib_add_ipaddr(rds_ibdev, ipaddr);

 	if (rds_ibdev_old != rds_ibdev) {
 		rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
 		rds_ib_dev_put(rds_ibdev_old);
 		return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
 	}
 	rds_ib_dev_put(rds_ibdev_old);

 	return 0;
 }

 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;
 	refcount_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);
 }

 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
 {
 	struct rds_ib_mr_pool *pool_1m = rds_ibdev->mr_1m_pool;

 	iinfo->rdma_mr_max = pool_1m->max_items;
 	iinfo->rdma_mr_size = pool_1m->fmr_attr.max_pages;
 }

 struct rds_ib_mr *rds_ib_reuse_mr(struct rds_ib_mr_pool *pool)
 {
 	struct rds_ib_mr *ibmr = NULL;
 	struct llist_node *ret;
 	unsigned long *flag;

 	preempt_disable();
 	flag = this_cpu_ptr(&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);
 		if (pool->pool_type == RDS_IB_MR_8K_POOL)
 			rds_ib_stats_inc(s_ib_rdma_mr_8k_reused);
 		else
 			rds_ib_stats_inc(s_ib_rdma_mr_1m_reused);
 	}

 	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();
 	}
 }

 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;
 	}
 }

 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 */
 			WARN_ON(!page->mapping && irqs_disabled());
 			set_page_dirty(page);
 			put_page(page);
 		}
 		kfree(ibmr->sg);

 		ibmr->sg = NULL;
 		ibmr->sg_len = 0;
 	}
 }

 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_mr_pool *pool = ibmr->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 unsigned int 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;
 	unsigned int count = 0;

 	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;
 		count++;
 	}
 	return count;
 }

 /*
  * 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.
  */
 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;
 	struct llist_node *clean_nodes;
 	struct llist_node *clean_tail;
 	LIST_HEAD(unmap_list);
 	unsigned long unpinned = 0;
 	unsigned int nfreed = 0, dirty_to_clean = 0, free_goal;

 	if (pool->pool_type == RDS_IB_MR_8K_POOL)
 		rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_flush);
 	else
 		rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_flush);

 	if (ibmr_ret) {
 		DEFINE_WAIT(wait);
 		while (!mutex_trylock(&pool->flush_lock)) {
 			ibmr = rds_ib_reuse_mr(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_mr(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_mr(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.
 	 */
 	dirty_to_clean = llist_append_to_list(&pool->drop_list, &unmap_list);
 	dirty_to_clean += 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;

 	if (pool->use_fastreg)
 		rds_ib_unreg_frmr(&unmap_list, &nfreed, &unpinned, free_goal);
 	else
 		rds_ib_unreg_fmr(&unmap_list, &nfreed, &unpinned, free_goal);

 	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(dirty_to_clean, &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 0;
 }

 struct rds_ib_mr *rds_ib_try_reuse_ibmr(struct rds_ib_mr_pool *pool)
 {
 	struct rds_ib_mr *ibmr = NULL;
 	int iter = 0;

 	if (atomic_read(&pool->dirty_count) >= pool->max_items_soft / 10)
 		queue_delayed_work(rds_ib_mr_wq, &pool->flush_worker, 10);

 	while (1) {
 		ibmr = rds_ib_reuse_mr(pool);
 		if (ibmr)
 			return ibmr;

 		if (atomic_inc_return(&pool->item_count) <= pool->max_items)
 			break;

 		atomic_dec(&pool->item_count);

 		if (++iter > 2) {
 			if (pool->pool_type == RDS_IB_MR_8K_POOL)
 				rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_depleted);
 			else
 				rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_depleted);
 			return ERR_PTR(-EAGAIN);
 		}

 		/* We do have some empty MRs. Flush them out. */
 		if (pool->pool_type == RDS_IB_MR_8K_POOL)
 			rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_wait);
 		else
 			rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_wait);

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

 	return ibmr;
 }

 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_mr_pool *pool = ibmr->pool;
 	struct rds_ib_device *rds_ibdev = ibmr->device;

 	rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);

 	/* Return it to the pool's free list */
 	if (rds_ibdev->use_fastreg)
 		rds_ib_free_frmr_list(ibmr);
 	else
 		rds_ib_free_fmr_list(ibmr);

 	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 / 5)
 		queue_delayed_work(rds_ib_mr_wq, &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.
 			 */
 			queue_delayed_work(rds_ib_mr_wq,
 					   &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) {
 		if (rds_ibdev->mr_8k_pool)
 			rds_ib_flush_mr_pool(rds_ibdev->mr_8k_pool, 0, NULL);

 		if (rds_ibdev->mr_1m_pool)
 			rds_ib_flush_mr_pool(rds_ibdev->mr_1m_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_connection *conn)
 {
 	struct rds_ib_device *rds_ibdev;
 	struct rds_ib_mr *ibmr = NULL;
 	struct rds_ib_connection *ic = NULL;
 	int ret;

 	rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
 	if (!rds_ibdev) {
 		ret = -ENODEV;
 		goto out;
 	}

 	if (conn)
 		ic = conn->c_transport_data;

 	if (!rds_ibdev->mr_8k_pool || !rds_ibdev->mr_1m_pool) {
 		ret = -ENODEV;
 		goto out;
 	}

 	if (rds_ibdev->use_fastreg)
 		ibmr = rds_ib_reg_frmr(rds_ibdev, ic, sg, nents, key_ret);
 	else
 		ibmr = rds_ib_reg_fmr(rds_ibdev, sg, nents, key_ret);
 	if (IS_ERR(ibmr)) {
 		ret = PTR_ERR(ibmr);
 		pr_warn("RDS/IB: rds_ib_get_mr failed (errno=%d)\n", ret);
 	} else {
 		return ibmr;
 	}

  out:
 	if (rds_ibdev)
 		rds_ib_dev_put(rds_ibdev);

 	return ERR_PTR(ret);
 }

 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);
 }

 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev,
 					     int pool_type)
 {
 	struct rds_ib_mr_pool *pool;

 	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 	if (!pool)
 		return ERR_PTR(-ENOMEM);

 	pool->pool_type = pool_type;
 	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);

 	if (pool_type == RDS_IB_MR_1M_POOL) {
 		/* +1 allows for unaligned MRs */
 		pool->fmr_attr.max_pages = RDS_MR_1M_MSG_SIZE + 1;
 		pool->max_items = rds_ibdev->max_1m_mrs;
 	} else {
 		/* pool_type == RDS_IB_MR_8K_POOL */
 		pool->fmr_attr.max_pages = RDS_MR_8K_MSG_SIZE + 1;
 		pool->max_items = rds_ibdev->max_8k_mrs;
 	}

 	pool->max_free_pinned = pool->max_items * pool->fmr_attr.max_pages / 4;
 	pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
 	pool->fmr_attr.page_shift = PAGE_SHIFT;
 	pool->max_items_soft = rds_ibdev->max_mrs * 3 / 4;
 	pool->use_fastreg = rds_ibdev->use_fastreg;

 	return pool;
 }

 int rds_ib_mr_init(void)
 {
 	rds_ib_mr_wq = alloc_workqueue("rds_mr_flushd", WQ_MEM_RECLAIM, 0);
 	if (!rds_ib_mr_wq)
 		return -ENOMEM;
 	return 0;
 }

 /* By the time this is called all the IB devices should have been torn down and
  * had their pools freed.  As each pool is freed its work struct is waited on,
  * so the pool flushing work queue should be idle by the time we get here.
  */
 void rds_ib_mr_exit(void)
 {
 	destroy_workqueue(rds_ib_mr_wq);
 }
	/*
	* 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_single_path.h"
	#include "ib_mr.h"

	struct workqueue_struct *rds_ib_mr_wq;

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

	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) {
	refcount_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)
	kfree_rcu(to_free, rcu);
	}

	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)
	return rds_ib_add_ipaddr(rds_ibdev, ipaddr);

	if (rds_ibdev_old != rds_ibdev) {
	rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
	rds_ib_dev_put(rds_ibdev_old);
	return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
	}
	rds_ib_dev_put(rds_ibdev_old);

	return 0;
	}

	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;
	refcount_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);
	}

	void rds_ib_get_mr_info(struct rds_ib_device rds_ibdev, struct rds_info_rdma_connection iinfo)
	{
	struct rds_ib_mr_pool *pool_1m = rds_ibdev->mr_1m_pool;

	iinfo->rdma_mr_max = pool_1m->max_items;
	iinfo->rdma_mr_size = pool_1m->fmr_attr.max_pages;
	}

	struct rds_ib_mr rds_ib_reuse_mr(struct rds_ib_mr_pool pool)
	{
	struct rds_ib_mr *ibmr = NULL;
	struct llist_node *ret;
	unsigned long *flag;

	preempt_disable();
	flag = this_cpu_ptr(&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);
	if (pool->pool_type == RDS_IB_MR_8K_POOL)
	rds_ib_stats_inc(s_ib_rdma_mr_8k_reused);
	else
	rds_ib_stats_inc(s_ib_rdma_mr_1m_reused);
	}

	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();
	}
	}

	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;
	}
	}

	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 */
	WARN_ON(!page->mapping && irqs_disabled());
	set_page_dirty(page);
	put_page(page);
	}
	kfree(ibmr->sg);

	ibmr->sg = NULL;
	ibmr->sg_len = 0;
	}
	}

	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_mr_pool *pool = ibmr->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 unsigned int 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;
	unsigned int count = 0;

	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;
	count++;
	}
	return count;
	}

	/*
	* 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.
	*/
	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;
	struct llist_node *clean_nodes;
	struct llist_node *clean_tail;
	LIST_HEAD(unmap_list);
	unsigned long unpinned = 0;
	unsigned int nfreed = 0, dirty_to_clean = 0, free_goal;

	if (pool->pool_type == RDS_IB_MR_8K_POOL)
	rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_flush);
	else
	rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_flush);

	if (ibmr_ret) {
	DEFINE_WAIT(wait);
	while (!mutex_trylock(&pool->flush_lock)) {
	ibmr = rds_ib_reuse_mr(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_mr(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_mr(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.
	*/
	dirty_to_clean = llist_append_to_list(&pool->drop_list, &unmap_list);
	dirty_to_clean += 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;

	if (pool->use_fastreg)
	rds_ib_unreg_frmr(&unmap_list, &nfreed, &unpinned, free_goal);
	else
	rds_ib_unreg_fmr(&unmap_list, &nfreed, &unpinned, free_goal);

	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(dirty_to_clean, &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 0;
	}

	struct rds_ib_mr rds_ib_try_reuse_ibmr(struct rds_ib_mr_pool pool)
	{
	struct rds_ib_mr *ibmr = NULL;
	int iter = 0;

	if (atomic_read(&pool->dirty_count) >= pool->max_items_soft / 10)
	queue_delayed_work(rds_ib_mr_wq, &pool->flush_worker, 10);

	while (1) {
	ibmr = rds_ib_reuse_mr(pool);
	if (ibmr)
	return ibmr;

	if (atomic_inc_return(&pool->item_count) <= pool->max_items)
	break;

	atomic_dec(&pool->item_count);

	if (++iter > 2) {
	if (pool->pool_type == RDS_IB_MR_8K_POOL)
	rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_depleted);
	else
	rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_depleted);
	return ERR_PTR(-EAGAIN);
	}

	/* We do have some empty MRs. Flush them out. */
	if (pool->pool_type == RDS_IB_MR_8K_POOL)
	rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_wait);
	else
	rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_wait);

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

	return ibmr;
	}

	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_mr_pool *pool = ibmr->pool;
	struct rds_ib_device *rds_ibdev = ibmr->device;

	rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);

	/* Return it to the pool's free list */
	if (rds_ibdev->use_fastreg)
	rds_ib_free_frmr_list(ibmr);
	else
	rds_ib_free_fmr_list(ibmr);

	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 / 5)
	queue_delayed_work(rds_ib_mr_wq, &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.
	*/
	queue_delayed_work(rds_ib_mr_wq,
	&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) {
	if (rds_ibdev->mr_8k_pool)
	rds_ib_flush_mr_pool(rds_ibdev->mr_8k_pool, 0, NULL);

	if (rds_ibdev->mr_1m_pool)
	rds_ib_flush_mr_pool(rds_ibdev->mr_1m_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_connection *conn)
	{
	struct rds_ib_device *rds_ibdev;
	struct rds_ib_mr *ibmr = NULL;
	struct rds_ib_connection *ic = NULL;
	int ret;

	rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
	if (!rds_ibdev) {
	ret = -ENODEV;
	goto out;
	}

	if (conn)
	ic = conn->c_transport_data;

	if (!rds_ibdev->mr_8k_pool \|\| !rds_ibdev->mr_1m_pool) {
	ret = -ENODEV;
	goto out;
	}

	if (rds_ibdev->use_fastreg)
	ibmr = rds_ib_reg_frmr(rds_ibdev, ic, sg, nents, key_ret);
	else
	ibmr = rds_ib_reg_fmr(rds_ibdev, sg, nents, key_ret);
	if (IS_ERR(ibmr)) {
	ret = PTR_ERR(ibmr);
	pr_warn("RDS/IB: rds_ib_get_mr failed (errno=%d)\n", ret);
	} else {
	return ibmr;
	}

	out:
	if (rds_ibdev)
	rds_ib_dev_put(rds_ibdev);

	return ERR_PTR(ret);
	}

	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);
	}

	struct rds_ib_mr_pool rds_ib_create_mr_pool(struct rds_ib_device rds_ibdev,
	int pool_type)
	{
	struct rds_ib_mr_pool *pool;

	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
	if (!pool)
	return ERR_PTR(-ENOMEM);

	pool->pool_type = pool_type;
	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);

	if (pool_type == RDS_IB_MR_1M_POOL) {
	/* +1 allows for unaligned MRs */
	pool->fmr_attr.max_pages = RDS_MR_1M_MSG_SIZE + 1;
	pool->max_items = rds_ibdev->max_1m_mrs;
	} else {
	/* pool_type == RDS_IB_MR_8K_POOL */
	pool->fmr_attr.max_pages = RDS_MR_8K_MSG_SIZE + 1;
	pool->max_items = rds_ibdev->max_8k_mrs;
	}

	pool->max_free_pinned = pool->max_items * pool->fmr_attr.max_pages / 4;
	pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
	pool->fmr_attr.page_shift = PAGE_SHIFT;
	pool->max_items_soft = rds_ibdev->max_mrs * 3 / 4;
	pool->use_fastreg = rds_ibdev->use_fastreg;

	return pool;
	}

	int rds_ib_mr_init(void)
	{
	rds_ib_mr_wq = alloc_workqueue("rds_mr_flushd", WQ_MEM_RECLAIM, 0);
	if (!rds_ib_mr_wq)
	return -ENOMEM;
	return 0;
	}

	/* By the time this is called all the IB devices should have been torn down and
	* had their pools freed. As each pool is freed its work struct is waited on,
	* so the pool flushing work queue should be idle by the time we get here.
	*/
	void rds_ib_mr_exit(void)
	{
	destroy_workqueue(rds_ib_mr_wq);
	}