1 files changed, 245 insertions, 69 deletions

diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index a54cd63f9e35..8f6e221c9f78 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -32,11 +32,16 @@
  */
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/rculist.h>
 
 #include "rds.h"
-#include "rdma.h"
 #include "ib.h"
+#include "xlist.h"
 
+struct workqueue_struct *rds_ib_fmr_wq;
+
+static DEFINE_PER_CPU(unsigned long, clean_list_grace);
+#define CLEAN_LIST_BUSY_BIT 0
 
 /*
  * This is stored as mr->r_trans_private.
@@ -45,7 +50,11 @@ struct rds_ib_mr {
 	struct rds_ib_device	*device;
 	struct rds_ib_mr_pool	*pool;
 	struct ib_fmr		*fmr;
-	struct list_head	list;
+
+	struct xlist_head	xlist;
+
+	/* unmap_list is for freeing */
+	struct list_head	unmap_list;
 	unsigned int		remap_count;
 
 	struct scatterlist	*sg;
@@ -59,14 +68,16 @@ struct rds_ib_mr {
  */
 struct rds_ib_mr_pool {
 	struct mutex		flush_lock;		/* serialize fmr invalidate */
-	struct work_struct	flush_worker;		/* flush worker */
+	struct delayed_work	flush_worker;		/* flush worker */
 
-	spinlock_t		list_lock;		/* protect variables below */
 	atomic_t		item_count;		/* total # of MRs */
 	atomic_t		dirty_count;		/* # dirty of MRs */
-	struct list_head	drop_list;		/* MRs that have reached their max_maps limit */
-	struct list_head	free_list;		/* unused MRs */
-	struct list_head	clean_list;		/* unused & unamapped MRs */
+
+	struct xlist_head	drop_list;		/* MRs that have reached their max_maps limit */
+	struct xlist_head	free_list;		/* unused MRs */
+	struct xlist_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;
@@ -74,7 +85,7 @@ struct rds_ib_mr_pool {
 	struct ib_fmr_attr	fmr_attr;
 };
 
-static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all);
+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);
 
@@ -83,16 +94,17 @@ static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
 	struct rds_ib_device *rds_ibdev;
 	struct rds_ib_ipaddr *i_ipaddr;
 
-	list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
-		spin_lock_irq(&rds_ibdev->spinlock);
-		list_for_each_entry(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
+	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) {
-				spin_unlock_irq(&rds_ibdev->spinlock);
+				atomic_inc(&rds_ibdev->refcount);
+				rcu_read_unlock();
 				return rds_ibdev;
 			}
 		}
-		spin_unlock_irq(&rds_ibdev->spinlock);
 	}
+	rcu_read_unlock();
 
 	return NULL;
 }
@@ -108,7 +120,7 @@ static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 	i_ipaddr->ipaddr = ipaddr;
 
 	spin_lock_irq(&rds_ibdev->spinlock);
-	list_add_tail(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
+	list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
 	spin_unlock_irq(&rds_ibdev->spinlock);
 
 	return 0;
@@ -116,17 +128,24 @@ static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 
 static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 {
-	struct rds_ib_ipaddr *i_ipaddr, *next;
+	struct rds_ib_ipaddr *i_ipaddr;
+	struct rds_ib_ipaddr *to_free = NULL;
+
 
 	spin_lock_irq(&rds_ibdev->spinlock);
-	list_for_each_entry_safe(i_ipaddr, next, &rds_ibdev->ipaddr_list, list) {
+	list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
 		if (i_ipaddr->ipaddr == ipaddr) {
-			list_del(&i_ipaddr->list);
-			kfree(i_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)
@@ -134,8 +153,10 @@ 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)
+	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);
 }
@@ -156,6 +177,7 @@ void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *con
 	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)
@@ -175,18 +197,18 @@ void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *
 	spin_unlock(&ib_nodev_conns_lock);
 
 	ic->rds_ibdev = NULL;
+	rds_ib_dev_put(rds_ibdev);
 }
 
-void __rds_ib_destroy_conns(struct list_head *list, spinlock_t *list_lock)
+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(list_lock);
-	list_splice(list, &tmp_list);
-	INIT_LIST_HEAD(list);
-	spin_unlock_irq(list_lock);
+	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);
@@ -200,12 +222,12 @@ struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
 	if (!pool)
 		return ERR_PTR(-ENOMEM);
 
-	INIT_LIST_HEAD(&pool->free_list);
-	INIT_LIST_HEAD(&pool->drop_list);
-	INIT_LIST_HEAD(&pool->clean_list);
+	INIT_XLIST_HEAD(&pool->free_list);
+	INIT_XLIST_HEAD(&pool->drop_list);
+	INIT_XLIST_HEAD(&pool->clean_list);
 	mutex_init(&pool->flush_lock);
-	spin_lock_init(&pool->list_lock);
-	INIT_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
+	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;
@@ -233,34 +255,60 @@ void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_co
 
 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
 {
-	flush_workqueue(rds_wq);
-	rds_ib_flush_mr_pool(pool, 1);
+	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 void refill_local(struct rds_ib_mr_pool *pool, struct xlist_head *xl,
+			 struct rds_ib_mr **ibmr_ret)
+{
+	struct xlist_head *ibmr_xl;
+	ibmr_xl = xlist_del_head_fast(xl);
+	*ibmr_ret = list_entry(ibmr_xl, struct rds_ib_mr, xlist);
+}
+
 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
 {
 	struct rds_ib_mr *ibmr = NULL;
-	unsigned long flags;
+	struct xlist_head *ret;
+	unsigned long *flag;
 
-	spin_lock_irqsave(&pool->list_lock, flags);
-	if (!list_empty(&pool->clean_list)) {
-		ibmr = list_entry(pool->clean_list.next, struct rds_ib_mr, list);
-		list_del_init(&ibmr->list);
-	}
-	spin_unlock_irqrestore(&pool->list_lock, flags);
+	preempt_disable();
+	flag = &__get_cpu_var(clean_list_grace);
+	set_bit(CLEAN_LIST_BUSY_BIT, flag);
+	ret = xlist_del_head(&pool->clean_list);
+	if (ret)
+		ibmr = list_entry(ret, struct rds_ib_mr, xlist);
 
+	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)
+		queue_delayed_work(rds_ib_fmr_wq, &pool->flush_worker, 10);
+
 	while (1) {
 		ibmr = rds_ib_reuse_fmr(pool);
 		if (ibmr)
@@ -287,19 +335,24 @@ static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
 
 		/* 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);
+		rds_ib_flush_mr_pool(pool, 0, &ibmr);
+		if (ibmr)
+			return ibmr;
 	}
 
-	ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
+	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_WRITE|
+			 IB_ACCESS_REMOTE_ATOMIC),
 			&pool->fmr_attr);
 	if (IS_ERR(ibmr->fmr)) {
 		err = PTR_ERR(ibmr->fmr);
@@ -367,7 +420,8 @@ static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibm
 	if (page_cnt > fmr_message_size)
 		return -EINVAL;
 
-	dma_pages = kmalloc(sizeof(u64) * page_cnt, GFP_ATOMIC);
+	dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
+				 rdsibdev_to_node(rds_ibdev));
 	if (!dma_pages)
 		return -ENOMEM;
 
@@ -441,7 +495,7 @@ static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 
 			/* FIXME we need a way to tell a r/w MR
 			 * from a r/o MR */
-			BUG_ON(in_interrupt());
+			BUG_ON(irqs_disabled());
 			set_page_dirty(page);
 			put_page(page);
 		}
@@ -477,33 +531,109 @@ static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int fr
 }
 
 /*
+ * given an xlist of mrs, put them all into the list_head for more processing
+ */
+static void xlist_append_to_list(struct xlist_head *xlist, struct list_head *list)
+{
+	struct rds_ib_mr *ibmr;
+	struct xlist_head splice;
+	struct xlist_head *cur;
+	struct xlist_head *next;
+
+	splice.next = NULL;
+	xlist_splice(xlist, &splice);
+	cur = splice.next;
+	while (cur) {
+		next = cur->next;
+		ibmr = list_entry(cur, struct rds_ib_mr, xlist);
+		list_add_tail(&ibmr->unmap_list, list);
+		cur = next;
+	}
+}
+
+/*
+ * this takes a list head of mrs and turns it into an xlist of clusters.
+ * each cluster has an xlist of MR_CLUSTER_SIZE mrs that are ready for
+ * reuse.
+ */
+static void list_append_to_xlist(struct rds_ib_mr_pool *pool,
+				struct list_head *list, struct xlist_head *xlist,
+				struct xlist_head **tail_ret)
+{
+	struct rds_ib_mr *ibmr;
+	struct xlist_head *cur_mr = xlist;
+	struct xlist_head *tail_mr = NULL;
+
+	list_for_each_entry(ibmr, list, unmap_list) {
+		tail_mr = &ibmr->xlist;
+		tail_mr->next = NULL;
+		cur_mr->next = tail_mr;
+		cur_mr = tail_mr;
+	}
+	*tail_ret = tail_mr;
+}
+
+/*
  * 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)
+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 xlist_head clean_xlist;
+	struct xlist_head *clean_tail;
 	LIST_HEAD(unmap_list);
 	LIST_HEAD(fmr_list);
 	unsigned long unpinned = 0;
-	unsigned long flags;
 	unsigned int nfreed = 0, ncleaned = 0, free_goal;
 	int ret = 0;
 
 	rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
 
-	mutex_lock(&pool->flush_lock);
+	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 (xlist_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;
+		}
+	}
 
-	spin_lock_irqsave(&pool->list_lock, flags);
 	/* Get the list of all MRs to be dropped. Ordering matters -
-	 * we want to put drop_list ahead of free_list. */
-	list_splice_init(&pool->free_list, &unmap_list);
-	list_splice_init(&pool->drop_list, &unmap_list);
+	 * we want to put drop_list ahead of free_list.
+	 */
+	xlist_append_to_list(&pool->drop_list, &unmap_list);
+	xlist_append_to_list(&pool->free_list, &unmap_list);
 	if (free_all)
-		list_splice_init(&pool->clean_list, &unmap_list);
-	spin_unlock_irqrestore(&pool->list_lock, flags);
+		xlist_append_to_list(&pool->clean_list, &unmap_list);
 
 	free_goal = rds_ib_flush_goal(pool, free_all);
 
@@ -511,19 +641,20 @@ static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
 		goto out;
 
 	/* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
-	list_for_each_entry(ibmr, &unmap_list, list)
+	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)\n", ret);
 
 	/* Now we can destroy the DMA mapping and unpin any pages */
-	list_for_each_entry_safe(ibmr, next, &unmap_list, list) {
+	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->list);
+			list_del(&ibmr->unmap_list);
 			ib_dealloc_fmr(ibmr->fmr);
 			kfree(ibmr);
 			nfreed++;
@@ -531,9 +662,27 @@ static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
 		ncleaned++;
 	}
 
-	spin_lock_irqsave(&pool->list_lock, flags);
-	list_splice(&unmap_list, &pool->clean_list);
-	spin_unlock_irqrestore(&pool->list_lock, flags);
+	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 xlist 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 xlist_del_head.
+		 *
+		 * This is pretty unlikely, but just in case  wait for an xlist grace period
+		 * here before adding anything back into the clean list.
+		 */
+		wait_clean_list_grace();
+
+		list_append_to_xlist(pool, &unmap_list, &clean_xlist, &clean_tail);
+		if (ibmr_ret)
+			refill_local(pool, &clean_xlist, ibmr_ret);
+
+		/* refill_local may have emptied our list */
+		if (!xlist_empty(&clean_xlist))
+			xlist_add(clean_xlist.next, clean_tail, &pool->clean_list);
+
+	}
 
 	atomic_sub(unpinned, &pool->free_pinned);
 	atomic_sub(ncleaned, &pool->dirty_count);
@@ -541,14 +690,35 @@ static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
 
 out:
 	mutex_unlock(&pool->flush_lock);
+	if (waitqueue_active(&pool->flush_wait))
+		wake_up(&pool->flush_wait);
+out_nolock:
 	return ret;
 }
 
+int rds_ib_fmr_init(void)
+{
+	rds_ib_fmr_wq = create_workqueue("rds_fmr_flushd");
+	if (!rds_ib_fmr_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_fmr_exit(void)
+{
+	destroy_workqueue(rds_ib_fmr_wq);
+}
+
 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);
+	struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);
 
-	rds_ib_flush_mr_pool(pool, 0);
+	rds_ib_flush_mr_pool(pool, 0, NULL);
 }
 
 void rds_ib_free_mr(void *trans_private, int invalidate)
@@ -556,47 +726,49 @@ 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;
-	unsigned long flags;
 
 	rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
 
 	/* Return it to the pool's free list */
-	spin_lock_irqsave(&pool->list_lock, flags);
 	if (ibmr->remap_count >= pool->fmr_attr.max_maps)
-		list_add(&ibmr->list, &pool->drop_list);
+		xlist_add(&ibmr->xlist, &ibmr->xlist, &pool->drop_list);
 	else
-		list_add(&ibmr->list, &pool->free_list);
+		xlist_add(&ibmr->xlist, &ibmr->xlist, &pool->free_list);
 
 	atomic_add(ibmr->sg_len, &pool->free_pinned);
 	atomic_inc(&pool->dirty_count);
-	spin_unlock_irqrestore(&pool->list_lock, flags);
 
 	/* 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)
-		queue_work(rds_wq, &pool->flush_worker);
+		queue_delayed_work(rds_ib_fmr_wq, &pool->flush_worker, 10);
 
 	if (invalidate) {
 		if (likely(!in_interrupt())) {
-			rds_ib_flush_mr_pool(pool, 0);
+			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_work(rds_wq, &pool->flush_worker);
+			queue_delayed_work(rds_ib_fmr_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) {
 		struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 
 		if (pool)
-			rds_ib_flush_mr_pool(pool, 0);
+			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,
@@ -628,6 +800,7 @@ void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 		printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
 
 	ibmr->device = rds_ibdev;
+	rds_ibdev = NULL;
 
  out:
 	if (ret) {
@@ -635,5 +808,8 @@ void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 			rds_ib_free_mr(ibmr, 0);
 		ibmr = ERR_PTR(ret);
 	}
+	if (rds_ibdev)
+		rds_ib_dev_put(rds_ibdev);
 	return ibmr;
 }
+