rhashtable: Revert nested table changes.

This reverts commits:

6a25478077d987edc5e2f880590a2bc5fcab4441
9dbbfb0ab6680c6a85609041011484e6658e7d3c
40137906c5f55c252194ef5834130383e639536f

It's too risky to put in this late in the release
cycle.  We'll put these changes into the next merge
window instead.

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 94 insertions, 316 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 70e94170af85..94f50cac91c6 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1420,32 +1420,26 @@ static struct shrinker glock_shrinker = {
  * @sdp: the filesystem
  * @bucket: the bucket
  *
- * Note that the function can be called multiple times on the same
- * object.  So the user must ensure that the function can cope with
- * that.
  */
 
 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
 {
         struct gfs2_glock *gl;
-        struct rhashtable_iter iter;
-
-        rhashtable_walk_enter(&gl_hash_table, &iter);
-
-        do {
-                gl = ERR_PTR(rhashtable_walk_start(&iter));
-                if (gl)
-                        continue;
+        struct rhash_head *pos;
+        const struct bucket_table *tbl;
+        int i;
 
-                while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
+        rcu_read_lock();
+        tbl = rht_dereference_rcu(gl_hash_table.tbl, &gl_hash_table);
+        for (i = 0; i < tbl->size; i++) {
+                rht_for_each_entry_rcu(gl, pos, tbl, i, gl_node) {
                         if ((gl->gl_name.ln_sbd == sdp) &&
                             lockref_get_not_dead(&gl->gl_lockref))
                                 examiner(gl);
-
-                rhashtable_walk_stop(&iter);
-        } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
-
-        rhashtable_walk_exit(&iter);
+                }
+        }
+        rcu_read_unlock();
+        cond_resched();
 }
 
 /**
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index f2e12a845910..5c132d3188be 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -61,7 +61,6 @@ struct rhlist_head {
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
- * @nest: Number of bits of first-level nested table.
  * @rehash: Current bucket being rehashed
  * @hash_rnd: Random seed to fold into hash
  * @locks_mask: Mask to apply before accessing locks[]
@@ -69,12 +68,10 @@ struct rhlist_head {
  * @walkers: List of active walkers
  * @rcu: RCU structure for freeing the table
  * @future_tbl: Table under construction during rehashing
- * @ntbl: Nested table used when out of memory.
  * @buckets: size * hash buckets
  */
 struct bucket_table {
         unsigned int            size;
-        unsigned int            nest;
         unsigned int            rehash;
         u32                     hash_rnd;
         unsigned int            locks_mask;
@@ -84,7 +81,7 @@ struct bucket_table {
 
         struct bucket_table __rcu *future_tbl;
 
-        struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp;
+        struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp;
 };
 
 /**
@@ -377,12 +374,6 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
                                  void *arg);
 void rhashtable_destroy(struct rhashtable *ht);
 
-struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
-                                            unsigned int hash);
-struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
-                                                   struct bucket_table *tbl,
-                                                   unsigned int hash);
-
 #define rht_dereference(p, ht) \
         rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht))
 
@@ -398,27 +389,6 @@ struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
 #define rht_entry(tpos, pos, member) \
         ({ tpos = container_of(pos, typeof(*tpos), member); 1; })
 
-static inline struct rhash_head __rcu *const *rht_bucket(
-        const struct bucket_table *tbl, unsigned int hash)
-{
-        return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) :
-                                     &tbl->buckets[hash];
-}
-
-static inline struct rhash_head __rcu **rht_bucket_var(
-        struct bucket_table *tbl, unsigned int hash)
-{
-        return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) :
-                                     &tbl->buckets[hash];
-}
-
-static inline struct rhash_head __rcu **rht_bucket_insert(
-        struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash)
-{
-        return unlikely(tbl->nest) ? rht_bucket_nested_insert(ht, tbl, hash) :
-                                     &tbl->buckets[hash];
-}
-
 /**
  * rht_for_each_continue - continue iterating over hash chain
  * @pos:        the &struct rhash_head to use as a loop cursor.
@@ -438,7 +408,7 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
  * @hash:       the hash value / bucket index
  */
 #define rht_for_each(pos, tbl, hash) \
-        rht_for_each_continue(pos, *rht_bucket(tbl, hash), tbl, hash)
+        rht_for_each_continue(pos, (tbl)->buckets[hash], tbl, hash)
 
 /**
  * rht_for_each_entry_continue - continue iterating over hash chain
@@ -463,7 +433,7 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
  * @member:     name of the &struct rhash_head within the hashable struct.
  */
 #define rht_for_each_entry(tpos, pos, tbl, hash, member)                \
-        rht_for_each_entry_continue(tpos, pos, *rht_bucket(tbl, hash),  \
+        rht_for_each_entry_continue(tpos, pos, (tbl)->buckets[hash],    \
                                     tbl, hash, member)
 
 /**
@@ -478,13 +448,13 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
  * This hash chain list-traversal primitive allows for the looped code to
  * remove the loop cursor from the list.
  */
-#define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member)           \
-        for (pos = rht_dereference_bucket(*rht_bucket(tbl, hash), tbl, hash), \
-             next = !rht_is_a_nulls(pos) ?                                    \
-                       rht_dereference_bucket(pos->next, tbl, hash) : NULL;   \
-             (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member);          \
-             pos = next,                                                      \
-             next = !rht_is_a_nulls(pos) ?                                    \
+#define rht_for_each_entry_safe(tpos, pos, next, tbl, hash, member)         \
+        for (pos = rht_dereference_bucket((tbl)->buckets[hash], tbl, hash), \
+             next = !rht_is_a_nulls(pos) ?                                  \
+                       rht_dereference_bucket(pos->next, tbl, hash) : NULL; \
+             (!rht_is_a_nulls(pos)) && rht_entry(tpos, pos, member);        \
+             pos = next,                                                    \
+             next = !rht_is_a_nulls(pos) ?                                  \
                        rht_dereference_bucket(pos->next, tbl, hash) : NULL)
 
 /**
@@ -515,7 +485,7 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
  * traversal is guarded by rcu_read_lock().
  */
 #define rht_for_each_rcu(pos, tbl, hash)                                \
-        rht_for_each_rcu_continue(pos, *rht_bucket(tbl, hash), tbl, hash)
+        rht_for_each_rcu_continue(pos, (tbl)->buckets[hash], tbl, hash)
 
 /**
  * rht_for_each_entry_rcu_continue - continue iterating over rcu hash chain
@@ -548,8 +518,8 @@ static inline struct rhash_head __rcu **rht_bucket_insert(
  * the _rcu mutation primitives such as rhashtable_insert() as long as the
  * traversal is guarded by rcu_read_lock().
  */
-#define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member)               \
-        rht_for_each_entry_rcu_continue(tpos, pos, *rht_bucket(tbl, hash), \
+#define rht_for_each_entry_rcu(tpos, pos, tbl, hash, member)            \
+        rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\
                                         tbl, hash, member)
 
 /**
@@ -595,7 +565,7 @@ static inline struct rhash_head *__rhashtable_lookup(
                 .ht = ht,
                 .key = key,
         };
-        struct bucket_table *tbl;
+        const struct bucket_table *tbl;
         struct rhash_head *he;
         unsigned int hash;
 
@@ -727,12 +697,8 @@ slow_path:
         }
 
         elasticity = ht->elasticity;
-        pprev = rht_bucket_insert(ht, tbl, hash);
-        data = ERR_PTR(-ENOMEM);
-        if (!pprev)
-                goto out;
-
-        rht_for_each_continue(head, *pprev, tbl, hash) {
+        pprev = &tbl->buckets[hash];
+        rht_for_each(head, tbl, hash) {
                 struct rhlist_head *plist;
                 struct rhlist_head *list;
 
@@ -770,7 +736,7 @@ slow_path:
         if (unlikely(rht_grow_above_100(ht, tbl)))
                 goto slow_path;
 
-        head = rht_dereference_bucket(*pprev, tbl, hash);
+        head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
         RCU_INIT_POINTER(obj->next, head);
         if (rhlist) {
@@ -780,7 +746,7 @@ slow_path:
                 RCU_INIT_POINTER(list->next, NULL);
         }
 
-        rcu_assign_pointer(*pprev, obj);
+        rcu_assign_pointer(tbl->buckets[hash], obj);
 
         atomic_inc(&ht->nelems);
         if (rht_grow_above_75(ht, tbl))
@@ -989,8 +955,8 @@ static inline int __rhashtable_remove_fast_one(
 
         spin_lock_bh(lock);
 
-        pprev = rht_bucket_var(tbl, hash);
-        rht_for_each_continue(he, *pprev, tbl, hash) {
+        pprev = &tbl->buckets[hash];
+        rht_for_each(he, tbl, hash) {
                 struct rhlist_head *list;
 
                 list = container_of(he, struct rhlist_head, rhead);
@@ -1141,8 +1107,8 @@ static inline int __rhashtable_replace_fast(
 
         spin_lock_bh(lock);
 
-        pprev = rht_bucket_var(tbl, hash);
-        rht_for_each_continue(he, *pprev, tbl, hash) {
+        pprev = &tbl->buckets[hash];
+        rht_for_each(he, tbl, hash) {
                 if (he != obj_old) {
                         pprev = &he->next;
                         continue;
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 172454e6b979..32d0ad058380 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -32,11 +32,6 @@
 #define HASH_MIN_SIZE           4U
 #define BUCKET_LOCKS_PER_CPU    32UL
 
-union nested_table {
-        union nested_table __rcu *table;
-        struct rhash_head __rcu *bucket;
-};
-
 static u32 head_hashfn(struct rhashtable *ht,
                        const struct bucket_table *tbl,
                        const struct rhash_head *he)
@@ -81,9 +76,6 @@ static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl,
         /* Never allocate more than 0.5 locks per bucket */
         size = min_t(unsigned int, size, tbl->size >> 1);
 
-        if (tbl->nest)
-                size = min(size, 1U << tbl->nest);
-
         if (sizeof(spinlock_t) != 0) {
                 tbl->locks = NULL;
 #ifdef CONFIG_NUMA
@@ -107,45 +99,8 @@ static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl,
         return 0;
 }
 
-static void nested_table_free(union nested_table *ntbl, unsigned int size)
-{
-        const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
-        const unsigned int len = 1 << shift;
-        unsigned int i;
-
-        ntbl = rcu_dereference_raw(ntbl->table);
-        if (!ntbl)
-                return;
-
-        if (size > len) {
-                size >>= shift;
-                for (i = 0; i < len; i++)
-                        nested_table_free(ntbl + i, size);
-        }
-
-        kfree(ntbl);
-}
-
-static void nested_bucket_table_free(const struct bucket_table *tbl)
-{
-        unsigned int size = tbl->size >> tbl->nest;
-        unsigned int len = 1 << tbl->nest;
-        union nested_table *ntbl;
-        unsigned int i;
-
-        ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
-
-        for (i = 0; i < len; i++)
-                nested_table_free(ntbl + i, size);
-
-        kfree(ntbl);
-}
-
 static void bucket_table_free(const struct bucket_table *tbl)
 {
-        if (tbl->nest)
-                nested_bucket_table_free(tbl);
-
         if (tbl)
                 kvfree(tbl->locks);
 
@@ -157,59 +112,6 @@ static void bucket_table_free_rcu(struct rcu_head *head)
         bucket_table_free(container_of(head, struct bucket_table, rcu));
 }
 
-static union nested_table *nested_table_alloc(struct rhashtable *ht,
-                                              union nested_table __rcu **prev,
-                                              unsigned int shifted,
-                                              unsigned int nhash)
-{
-        union nested_table *ntbl;
-        int i;
-
-        ntbl = rcu_dereference(*prev);
-        if (ntbl)
-                return ntbl;
-
-        ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC);
-
-        if (ntbl && shifted) {
-                for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0].bucket); i++)
-                        INIT_RHT_NULLS_HEAD(ntbl[i].bucket, ht,
-                                            (i << shifted) | nhash);
-        }
-
-        rcu_assign_pointer(*prev, ntbl);
-
-        return ntbl;
-}
-
-static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht,
-                                                      size_t nbuckets,
-                                                      gfp_t gfp)
-{
-        const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
-        struct bucket_table *tbl;
-        size_t size;
-
-        if (nbuckets < (1 << (shift + 1)))
-                return NULL;
-
-        size = sizeof(*tbl) + sizeof(tbl->buckets[0]);
-
-        tbl = kzalloc(size, gfp);
-        if (!tbl)
-                return NULL;
-
-        if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets,
-                                0, 0)) {
-                kfree(tbl);
-                return NULL;
-        }
-
-        tbl->nest = (ilog2(nbuckets) - 1) % shift + 1;
-
-        return tbl;
-}
-
 static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
                                                size_t nbuckets,
                                                gfp_t gfp)
@@ -224,17 +126,10 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
                 tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY);
         if (tbl == NULL && gfp == GFP_KERNEL)
                 tbl = vzalloc(size);
-
-        size = nbuckets;
-
-        if (tbl == NULL && gfp != GFP_KERNEL) {
-                tbl = nested_bucket_table_alloc(ht, nbuckets, gfp);
-                nbuckets = 0;
-        }
         if (tbl == NULL)
                 return NULL;
 
-        tbl->size = size;
+        tbl->size = nbuckets;
 
         if (alloc_bucket_locks(ht, tbl, gfp) < 0) {
                 bucket_table_free(tbl);
@@ -269,17 +164,12 @@ static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
         struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
         struct bucket_table *new_tbl = rhashtable_last_table(ht,
                 rht_dereference_rcu(old_tbl->future_tbl, ht));
-        struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash);
-        int err = -EAGAIN;
+        struct rhash_head __rcu **pprev = &old_tbl->buckets[old_hash];
+        int err = -ENOENT;
         struct rhash_head *head, *next, *entry;
         spinlock_t *new_bucket_lock;
         unsigned int new_hash;
 
-        if (new_tbl->nest)
-                goto out;
-
-        err = -ENOENT;
-
         rht_for_each(entry, old_tbl, old_hash) {
                 err = 0;
                 next = rht_dereference_bucket(entry->next, old_tbl, old_hash);
@@ -312,26 +202,19 @@ out:
         return err;
 }
 
-static int rhashtable_rehash_chain(struct rhashtable *ht,
+static void rhashtable_rehash_chain(struct rhashtable *ht,
                                     unsigned int old_hash)
 {
         struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
         spinlock_t *old_bucket_lock;
-        int err;
 
         old_bucket_lock = rht_bucket_lock(old_tbl, old_hash);
 
         spin_lock_bh(old_bucket_lock);
-        while (!(err = rhashtable_rehash_one(ht, old_hash)))
+        while (!rhashtable_rehash_one(ht, old_hash))
                 ;
-
-        if (err == -ENOENT) {
-                old_tbl->rehash++;
-                err = 0;
-        }
+        old_tbl->rehash++;
         spin_unlock_bh(old_bucket_lock);
-
-        return err;
 }
 
 static int rhashtable_rehash_attach(struct rhashtable *ht,
@@ -363,17 +246,13 @@ static int rhashtable_rehash_table(struct rhashtable *ht)
         struct bucket_table *new_tbl;
         struct rhashtable_walker *walker;
         unsigned int old_hash;
-        int err;
 
         new_tbl = rht_dereference(old_tbl->future_tbl, ht);
         if (!new_tbl)
                 return 0;
 
-        for (old_hash = 0; old_hash < old_tbl->size; old_hash++) {
-                err = rhashtable_rehash_chain(ht, old_hash);
-                if (err)
-                        return err;
-        }
+        for (old_hash = 0; old_hash < old_tbl->size; old_hash++)
+                rhashtable_rehash_chain(ht, old_hash);
 
         /* Publish the new table pointer. */
         rcu_assign_pointer(ht->tbl, new_tbl);
@@ -392,16 +271,31 @@ static int rhashtable_rehash_table(struct rhashtable *ht)
         return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0;
 }
 
-static int rhashtable_rehash_alloc(struct rhashtable *ht,
-                                   struct bucket_table *old_tbl,
-                                   unsigned int size)
+/**
+ * rhashtable_expand - Expand hash table while allowing concurrent lookups
+ * @ht:         the hash table to expand
+ *
+ * A secondary bucket array is allocated and the hash entries are migrated.
+ *
+ * This function may only be called in a context where it is safe to call
+ * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
+ *
+ * The caller must ensure that no concurrent resizing occurs by holding
+ * ht->mutex.
+ *
+ * It is valid to have concurrent insertions and deletions protected by per
+ * bucket locks or concurrent RCU protected lookups and traversals.
+ */
+static int rhashtable_expand(struct rhashtable *ht)
 {
-        struct bucket_table *new_tbl;
+        struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
         int err;
 
         ASSERT_RHT_MUTEX(ht);
 
-        new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
+        old_tbl = rhashtable_last_table(ht, old_tbl);
+
+        new_tbl = bucket_table_alloc(ht, old_tbl->size * 2, GFP_KERNEL);
         if (new_tbl == NULL)
                 return -ENOMEM;
 
@@ -430,9 +324,12 @@ static int rhashtable_rehash_alloc(struct rhashtable *ht,
  */
 static int rhashtable_shrink(struct rhashtable *ht)
 {
-        struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);
+        struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
         unsigned int nelems = atomic_read(&ht->nelems);
         unsigned int size = 0;
+        int err;
+
+        ASSERT_RHT_MUTEX(ht);
 
         if (nelems)
                 size = roundup_pow_of_two(nelems * 3 / 2);
@@ -445,7 +342,15 @@ static int rhashtable_shrink(struct rhashtable *ht)
         if (rht_dereference(old_tbl->future_tbl, ht))
                 return -EEXIST;
 
-        return rhashtable_rehash_alloc(ht, old_tbl, size);
+        new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
+        if (new_tbl == NULL)
+                return -ENOMEM;
+
+        err = rhashtable_rehash_attach(ht, old_tbl, new_tbl);
+        if (err)
+                bucket_table_free(new_tbl);
+
+        return err;
 }
 
 static void rht_deferred_worker(struct work_struct *work)
@@ -461,14 +366,11 @@ static void rht_deferred_worker(struct work_struct *work)
         tbl = rhashtable_last_table(ht, tbl);
 
         if (rht_grow_above_75(ht, tbl))
-                err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2);
+                rhashtable_expand(ht);
         else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl))
-                err = rhashtable_shrink(ht);
-        else if (tbl->nest)
-                err = rhashtable_rehash_alloc(ht, tbl, tbl->size);
+                rhashtable_shrink(ht);
 
-        if (!err)
-                err = rhashtable_rehash_table(ht);
+        err = rhashtable_rehash_table(ht);
 
         mutex_unlock(&ht->mutex);
 
@@ -537,8 +439,8 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
         int elasticity;
 
         elasticity = ht->elasticity;
-        pprev = rht_bucket_var(tbl, hash);
-        rht_for_each_continue(head, *pprev, tbl, hash) {
+        pprev = &tbl->buckets[hash];
+        rht_for_each(head, tbl, hash) {
                 struct rhlist_head *list;
                 struct rhlist_head *plist;
 
@@ -575,7 +477,6 @@ static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
                                                   struct rhash_head *obj,
                                                   void *data)
 {
-        struct rhash_head __rcu **pprev;
         struct bucket_table *new_tbl;
         struct rhash_head *head;
 
@@ -598,11 +499,7 @@ static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
         if (unlikely(rht_grow_above_100(ht, tbl)))
                 return ERR_PTR(-EAGAIN);
 
-        pprev = rht_bucket_insert(ht, tbl, hash);
-        if (!pprev)
-                return ERR_PTR(-ENOMEM);
-
-        head = rht_dereference_bucket(*pprev, tbl, hash);
+        head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
         RCU_INIT_POINTER(obj->next, head);
         if (ht->rhlist) {
@@ -612,7 +509,7 @@ static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
                 RCU_INIT_POINTER(list->next, NULL);
         }
 
-        rcu_assign_pointer(*pprev, obj);
+        rcu_assign_pointer(tbl->buckets[hash], obj);
 
         atomic_inc(&ht->nelems);
         if (rht_grow_above_75(ht, tbl))
@@ -1078,7 +975,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
                                  void (*free_fn)(void *ptr, void *arg),
                                  void *arg)
 {
-        struct bucket_table *tbl;
+        const struct bucket_table *tbl;
         unsigned int i;
 
         cancel_work_sync(&ht->run_work);
@@ -1089,7 +986,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
                 for (i = 0; i < tbl->size; i++) {
                         struct rhash_head *pos, *next;
 
-                        for (pos = rht_dereference(*rht_bucket(tbl, i), ht),
+                        for (pos = rht_dereference(tbl->buckets[i], ht),
                              next = !rht_is_a_nulls(pos) ?
                                         rht_dereference(pos->next, ht) : NULL;
                              !rht_is_a_nulls(pos);
@@ -1110,70 +1007,3 @@ void rhashtable_destroy(struct rhashtable *ht)
         return rhashtable_free_and_destroy(ht, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(rhashtable_destroy);
-
-struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
-                                            unsigned int hash)
-{
-        const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
-        static struct rhash_head __rcu *rhnull =
-                (struct rhash_head __rcu *)NULLS_MARKER(0);
-        unsigned int index = hash & ((1 << tbl->nest) - 1);
-        unsigned int size = tbl->size >> tbl->nest;
-        unsigned int subhash = hash;
-        union nested_table *ntbl;
-
-        ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
-        ntbl = rht_dereference_bucket(ntbl[index].table, tbl, hash);
-        subhash >>= tbl->nest;
-
-        while (ntbl && size > (1 << shift)) {
-                index = subhash & ((1 << shift) - 1);
-                ntbl = rht_dereference_bucket(ntbl[index].table, tbl, hash);
-                size >>= shift;
-                subhash >>= shift;
-        }
-
-        if (!ntbl)
-                return &rhnull;
-
-        return &ntbl[subhash].bucket;
-
-}
-EXPORT_SYMBOL_GPL(rht_bucket_nested);
-
-struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
-                                                   struct bucket_table *tbl,
-                                                   unsigned int hash)
-{
-        const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
-        unsigned int index = hash & ((1 << tbl->nest) - 1);
-        unsigned int size = tbl->size >> tbl->nest;
-        union nested_table *ntbl;
-        unsigned int shifted;
-        unsigned int nhash;
-
-        ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]);
-        hash >>= tbl->nest;
-        nhash = index;
-        shifted = tbl->nest;
-        ntbl = nested_table_alloc(ht, &ntbl[index].table,
-                                  size <= (1 << shift) ? shifted : 0, nhash);
-
-        while (ntbl && size > (1 << shift)) {
-                index = hash & ((1 << shift) - 1);
-                size >>= shift;
-                hash >>= shift;
-                nhash |= index << shifted;
-                shifted += shift;
-                ntbl = nested_table_alloc(ht, &ntbl[index].table,
-                                          size <= (1 << shift) ? shifted : 0,
-                                          nhash);
-        }
-
-        if (!ntbl)
-                return NULL;
-
-        return &ntbl[hash].bucket;
-
-}
-EXPORT_SYMBOL_GPL(rht_bucket_nested_insert);
diff --git a/net/tipc/net.c b/net/tipc/net.c
index ab8a2d5d1e32..28bf4feeb81c 100644
--- a/net/tipc/net.c
+++ b/net/tipc/net.c
@@ -110,10 +110,6 @@ int tipc_net_start(struct net *net, u32 addr)
         char addr_string[16];
 
         tn->own_addr = addr;
-
-        /* Ensure that the new address is visible before we reinit. */
-        smp_mb();
-
         tipc_named_reinit(net);
         tipc_sk_reinit(net);
 
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 370a5912bcb5..800caaa699a1 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -384,6 +384,8 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
         INIT_LIST_HEAD(&tsk->publications);
         msg = &tsk->phdr;
         tn = net_generic(sock_net(sk), tipc_net_id);
+        tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
+                      NAMED_H_SIZE, 0);
 
         /* Finish initializing socket data structures */
         sock->ops = ops;
@@ -393,13 +395,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
                 pr_warn("Socket create failed; port number exhausted\n");
                 return -EINVAL;
         }
-
-        /* Ensure tsk is visible before we read own_addr. */
-        smp_mb();
-
-        tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
-                      NAMED_H_SIZE, 0);
-
         msg_set_origport(msg, tsk->portid);
         setup_timer(&sk->sk_timer, tipc_sk_timeout, (unsigned long)tsk);
         sk->sk_shutdown = 0;
@@ -2274,27 +2269,24 @@ static int tipc_sk_withdraw(struct tipc_sock *tsk, uint scope,
 void tipc_sk_reinit(struct net *net)
 {
         struct tipc_net *tn = net_generic(net, tipc_net_id);
-        struct rhashtable_iter iter;
+        const struct bucket_table *tbl;
+        struct rhash_head *pos;
         struct tipc_sock *tsk;
         struct tipc_msg *msg;
+        int i;
 
-        rhashtable_walk_enter(&tn->sk_rht, &iter);
-
-        do {
-                tsk = ERR_PTR(rhashtable_walk_start(&iter));
-                if (tsk)
-                        continue;
-
-                while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
+        rcu_read_lock();
+        tbl = rht_dereference_rcu((&tn->sk_rht)->tbl, &tn->sk_rht);
+        for (i = 0; i < tbl->size; i++) {
+                rht_for_each_entry_rcu(tsk, pos, tbl, i, node) {
                         spin_lock_bh(&tsk->sk.sk_lock.slock);
                         msg = &tsk->phdr;
                         msg_set_prevnode(msg, tn->own_addr);
                         msg_set_orignode(msg, tn->own_addr);
                         spin_unlock_bh(&tsk->sk.sk_lock.slock);
                 }
-
-                rhashtable_walk_stop(&iter);
-        } while (tsk == ERR_PTR(-EAGAIN));
+        }
+        rcu_read_unlock();
 }
 
 static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid)