Merge branch 'rhashtable-New-features-in-walk-and-bucket'

Tom Herbert says:

====================
rhashtable: New features in walk and bucket

This patch contains some changes to related rhashtable:

- Above allow rhashtable_walk_start to return void
- Add a functon to peek at the next entry during a walk
- Abstract out function to compute a has for a table
- A library function to alloc a spinlocks bucket array
- Call the above function for rhashtable locks allocation

Tested: Exercised using various operations on an ILA xlat
table.

v2:
 - Apply feedback from Herbert. Don't change semantics of resize
   event reporting and -EAGAIN, just simplify API for callers that
   ignore those.
 - Add end_of_table in iter to reliably tell when the iterator has
   reached to the eno.
====================

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

3 files changed, 34 insertions, 12 deletions

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 361c08e35dbc..c9df2527e0cd 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -207,6 +207,7 @@ struct rhashtable_iter {
 	struct rhashtable_walker walker;
 	unsigned int slot;
 	unsigned int skip;
+	bool end_of_table;
 };
 
 static inline unsigned long rht_marker(const struct rhashtable *ht, u32 hash)
@@ -239,34 +240,42 @@ static inline unsigned int rht_bucket_index(const struct bucket_table *tbl,
 	return (hash >> RHT_HASH_RESERVED_SPACE) & (tbl->size - 1);
 }
 
-static inline unsigned int rht_key_hashfn(
-	struct rhashtable *ht, const struct bucket_table *tbl,
-	const void *key, const struct rhashtable_params params)
+static inline unsigned int rht_key_get_hash(struct rhashtable *ht,
+	const void *key, const struct rhashtable_params params,
+	unsigned int hash_rnd)
 {
 	unsigned int hash;
 
 	/* params must be equal to ht->p if it isn't constant. */
 	if (!__builtin_constant_p(params.key_len))
-		hash = ht->p.hashfn(key, ht->key_len, tbl->hash_rnd);
+		hash = ht->p.hashfn(key, ht->key_len, hash_rnd);
 	else if (params.key_len) {
 		unsigned int key_len = params.key_len;
 
 		if (params.hashfn)
-			hash = params.hashfn(key, key_len, tbl->hash_rnd);
+			hash = params.hashfn(key, key_len, hash_rnd);
 		else if (key_len & (sizeof(u32) - 1))
-			hash = jhash(key, key_len, tbl->hash_rnd);
+			hash = jhash(key, key_len, hash_rnd);
 		else
-			hash = jhash2(key, key_len / sizeof(u32),
-				      tbl->hash_rnd);
+			hash = jhash2(key, key_len / sizeof(u32), hash_rnd);
 	} else {
 		unsigned int key_len = ht->p.key_len;
 
 		if (params.hashfn)
-			hash = params.hashfn(key, key_len, tbl->hash_rnd);
+			hash = params.hashfn(key, key_len, hash_rnd);
 		else
-			hash = jhash(key, key_len, tbl->hash_rnd);
+			hash = jhash(key, key_len, hash_rnd);
 	}
 
+	return hash;
+}
+
+static inline unsigned int rht_key_hashfn(
+	struct rhashtable *ht, const struct bucket_table *tbl,
+	const void *key, const struct rhashtable_params params)
+{
+	unsigned int hash = rht_key_get_hash(ht, key, params, tbl->hash_rnd);
+
 	return rht_bucket_index(tbl, hash);
 }
 
@@ -378,8 +387,15 @@ void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
 void rhashtable_walk_exit(struct rhashtable_iter *iter);
-int rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU);
+int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires(RCU);
+
+static inline void rhashtable_walk_start(struct rhashtable_iter *iter)
+{
+	(void)rhashtable_walk_start_check(iter);
+}
+
 void *rhashtable_walk_next(struct rhashtable_iter *iter);
+void *rhashtable_walk_peek(struct rhashtable_iter *iter);
 void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU);
 
 void rhashtable_free_and_destroy(struct rhashtable *ht,
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index a39186194cd6..10fd28b118ee 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -414,4 +414,10 @@ extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 #define atomic_dec_and_lock(atomic, lock) \
 		__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 
+int alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *lock_mask,
+			   size_t max_size, unsigned int cpu_mult,
+			   gfp_t gfp);
+
+void free_bucket_spinlocks(spinlock_t *locks);
+
 #endif /* __LINUX_SPINLOCK_H */
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 906a9c0efa71..6f79415f6634 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -116,7 +116,7 @@ extern struct percpu_counter sctp_sockets_allocated;
 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
 
-int sctp_transport_walk_start(struct rhashtable_iter *iter);
+void sctp_transport_walk_start(struct rhashtable_iter *iter);
 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
 struct sctp_transport *sctp_transport_get_next(struct net *net,
 			struct rhashtable_iter *iter);