rhashtable: Revert nested table changes.

This reverts commits:

6a254780
9dbbfb0a
40137906

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: NDavid S. Miller <davem@davemloft.net>

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();
 }
 
 /**

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 @@ static inline void *__rhashtable_insert_fast(
 	}
 
 	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 @@ static inline void *__rhashtable_insert_fast(
 	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 @@ static inline void *__rhashtable_insert_fast(
 		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;

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 @@ static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
 	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);

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);
 

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)