rhashtable: split rhashtable.h

Due to the use of rhashtables in net namespaces,
rhashtable.h is included in lots of the kernel,
so a small changes can required a large recompilation.
This makes development painful.

This patch splits out rhashtable-types.h which just includes
the major type declarations, and does not include (non-trivial)
inline code.  rhashtable.h is no longer included by anything
in the include/ directory.
Common include files only include rhashtable-types.h so a large
recompilation is only triggered when that changes.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 144 insertions, 128 deletions

diff --git a/include/linux/ipc.h b/include/linux/ipc.h
index 6cc2df7f7ac9..e1c9eea6015b 100644
--- a/include/linux/ipc.h
+++ b/include/linux/ipc.h
@@ -4,7 +4,7 @@
 
 #include <linux/spinlock.h>
 #include <linux/uidgid.h>
-#include <linux/rhashtable.h>
+#include <linux/rhashtable-types.h>
 #include <uapi/linux/ipc.h>
 #include <linux/refcount.h>
 
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index b5630c8eb2f3..6cea726612b7 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -9,7 +9,7 @@
 #include <linux/nsproxy.h>
 #include <linux/ns_common.h>
 #include <linux/refcount.h>
-#include <linux/rhashtable.h>
+#include <linux/rhashtable-types.h>
 
 struct user_namespace;
 
diff --git a/include/linux/mroute_base.h b/include/linux/mroute_base.h
index d633f737b3c6..fd436cdd4725 100644
--- a/include/linux/mroute_base.h
+++ b/include/linux/mroute_base.h
@@ -2,7 +2,7 @@
 #define __LINUX_MROUTE_BASE_H
 
 #include <linux/netdevice.h>
-#include <linux/rhashtable.h>
+#include <linux/rhashtable-types.h>
 #include <linux/spinlock.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
diff --git a/include/linux/rhashtable-types.h b/include/linux/rhashtable-types.h
new file mode 100644
index 000000000000..9740063ff13b
--- /dev/null
+++ b/include/linux/rhashtable-types.h
@@ -0,0 +1,139 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Resizable, Scalable, Concurrent Hash Table
+ *
+ * Simple structures that might be needed in include
+ * files.
+ */
+
+#ifndef _LINUX_RHASHTABLE_TYPES_H
+#define _LINUX_RHASHTABLE_TYPES_H
+
+#include <linux/atomic.h>
+#include <linux/compiler.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+struct rhash_head {
+	struct rhash_head __rcu		*next;
+};
+
+struct rhlist_head {
+	struct rhash_head		rhead;
+	struct rhlist_head __rcu	*next;
+};
+
+struct bucket_table;
+
+/**
+ * struct rhashtable_compare_arg - Key for the function rhashtable_compare
+ * @ht: Hash table
+ * @key: Key to compare against
+ */
+struct rhashtable_compare_arg {
+	struct rhashtable *ht;
+	const void *key;
+};
+
+typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed);
+typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 len, u32 seed);
+typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg,
+			       const void *obj);
+
+/**
+ * struct rhashtable_params - Hash table construction parameters
+ * @nelem_hint: Hint on number of elements, should be 75% of desired size
+ * @key_len: Length of key
+ * @key_offset: Offset of key in struct to be hashed
+ * @head_offset: Offset of rhash_head in struct to be hashed
+ * @max_size: Maximum size while expanding
+ * @min_size: Minimum size while shrinking
+ * @locks_mul: Number of bucket locks to allocate per cpu (default: 32)
+ * @automatic_shrinking: Enable automatic shrinking of tables
+ * @nulls_base: Base value to generate nulls marker
+ * @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash)
+ * @obj_hashfn: Function to hash object
+ * @obj_cmpfn: Function to compare key with object
+ */
+struct rhashtable_params {
+	u16			nelem_hint;
+	u16			key_len;
+	u16			key_offset;
+	u16			head_offset;
+	unsigned int		max_size;
+	u16			min_size;
+	bool			automatic_shrinking;
+	u8			locks_mul;
+	u32			nulls_base;
+	rht_hashfn_t		hashfn;
+	rht_obj_hashfn_t	obj_hashfn;
+	rht_obj_cmpfn_t		obj_cmpfn;
+};
+
+/**
+ * struct rhashtable - Hash table handle
+ * @tbl: Bucket table
+ * @key_len: Key length for hashfn
+ * @max_elems: Maximum number of elements in table
+ * @p: Configuration parameters
+ * @rhlist: True if this is an rhltable
+ * @run_work: Deferred worker to expand/shrink asynchronously
+ * @mutex: Mutex to protect current/future table swapping
+ * @lock: Spin lock to protect walker list
+ * @nelems: Number of elements in table
+ */
+struct rhashtable {
+	struct bucket_table __rcu	*tbl;
+	unsigned int			key_len;
+	unsigned int			max_elems;
+	struct rhashtable_params	p;
+	bool				rhlist;
+	struct work_struct		run_work;
+	struct mutex                    mutex;
+	spinlock_t			lock;
+	atomic_t			nelems;
+};
+
+/**
+ * struct rhltable - Hash table with duplicate objects in a list
+ * @ht: Underlying rhtable
+ */
+struct rhltable {
+	struct rhashtable ht;
+};
+
+/**
+ * struct rhashtable_walker - Hash table walker
+ * @list: List entry on list of walkers
+ * @tbl: The table that we were walking over
+ */
+struct rhashtable_walker {
+	struct list_head list;
+	struct bucket_table *tbl;
+};
+
+/**
+ * struct rhashtable_iter - Hash table iterator
+ * @ht: Table to iterate through
+ * @p: Current pointer
+ * @list: Current hash list pointer
+ * @walker: Associated rhashtable walker
+ * @slot: Current slot
+ * @skip: Number of entries to skip in slot
+ */
+struct rhashtable_iter {
+	struct rhashtable *ht;
+	struct rhash_head *p;
+	struct rhlist_head *list;
+	struct rhashtable_walker walker;
+	unsigned int slot;
+	unsigned int skip;
+	bool end_of_table;
+};
+
+int rhashtable_init(struct rhashtable *ht,
+		    const struct rhashtable_params *params);
+int rhltable_init(struct rhltable *hlt,
+		  const struct rhashtable_params *params);
+
+#endif /* _LINUX_RHASHTABLE_TYPES_H */
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 4e1f535c2034..48754ab07cdf 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
@@ -17,16 +18,14 @@
 #ifndef _LINUX_RHASHTABLE_H
 #define _LINUX_RHASHTABLE_H
 
-#include <linux/atomic.h>
-#include <linux/compiler.h>
 #include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/jhash.h>
 #include <linux/list_nulls.h>
 #include <linux/workqueue.h>
-#include <linux/mutex.h>
 #include <linux/rculist.h>
 
+#include <linux/rhashtable-types.h>
 /*
  * The end of the chain is marked with a special nulls marks which has
  * the following format:
@@ -64,15 +63,6 @@
  */
 #define RHT_ELASTICITY	16u
 
-struct rhash_head {
-	struct rhash_head __rcu		*next;
-};
-
-struct rhlist_head {
-	struct rhash_head		rhead;
-	struct rhlist_head __rcu	*next;
-};
-
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
@@ -102,114 +92,6 @@ struct bucket_table {
 	struct rhash_head __rcu *buckets[] ____cacheline_aligned_in_smp;
 };
 
-/**
- * struct rhashtable_compare_arg - Key for the function rhashtable_compare
- * @ht: Hash table
- * @key: Key to compare against
- */
-struct rhashtable_compare_arg {
-	struct rhashtable *ht;
-	const void *key;
-};
-
-typedef u32 (*rht_hashfn_t)(const void *data, u32 len, u32 seed);
-typedef u32 (*rht_obj_hashfn_t)(const void *data, u32 len, u32 seed);
-typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg,
-			       const void *obj);
-
-struct rhashtable;
-
-/**
- * struct rhashtable_params - Hash table construction parameters
- * @nelem_hint: Hint on number of elements, should be 75% of desired size
- * @key_len: Length of key
- * @key_offset: Offset of key in struct to be hashed
- * @head_offset: Offset of rhash_head in struct to be hashed
- * @max_size: Maximum size while expanding
- * @min_size: Minimum size while shrinking
- * @locks_mul: Number of bucket locks to allocate per cpu (default: 32)
- * @automatic_shrinking: Enable automatic shrinking of tables
- * @nulls_base: Base value to generate nulls marker
- * @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash)
- * @obj_hashfn: Function to hash object
- * @obj_cmpfn: Function to compare key with object
- */
-struct rhashtable_params {
-	u16			nelem_hint;
-	u16			key_len;
-	u16			key_offset;
-	u16			head_offset;
-	unsigned int		max_size;
-	u16			min_size;
-	bool			automatic_shrinking;
-	u8			locks_mul;
-	u32			nulls_base;
-	rht_hashfn_t		hashfn;
-	rht_obj_hashfn_t	obj_hashfn;
-	rht_obj_cmpfn_t		obj_cmpfn;
-};
-
-/**
- * struct rhashtable - Hash table handle
- * @tbl: Bucket table
- * @key_len: Key length for hashfn
- * @max_elems: Maximum number of elements in table
- * @p: Configuration parameters
- * @rhlist: True if this is an rhltable
- * @run_work: Deferred worker to expand/shrink asynchronously
- * @mutex: Mutex to protect current/future table swapping
- * @lock: Spin lock to protect walker list
- * @nelems: Number of elements in table
- */
-struct rhashtable {
-	struct bucket_table __rcu	*tbl;
-	unsigned int			key_len;
-	unsigned int			max_elems;
-	struct rhashtable_params	p;
-	bool				rhlist;
-	struct work_struct		run_work;
-	struct mutex                    mutex;
-	spinlock_t			lock;
-	atomic_t			nelems;
-};
-
-/**
- * struct rhltable - Hash table with duplicate objects in a list
- * @ht: Underlying rhtable
- */
-struct rhltable {
-	struct rhashtable ht;
-};
-
-/**
- * struct rhashtable_walker - Hash table walker
- * @list: List entry on list of walkers
- * @tbl: The table that we were walking over
- */
-struct rhashtable_walker {
-	struct list_head list;
-	struct bucket_table *tbl;
-};
-
-/**
- * struct rhashtable_iter - Hash table iterator
- * @ht: Table to iterate through
- * @p: Current pointer
- * @list: Current hash list pointer
- * @walker: Associated rhashtable walker
- * @slot: Current slot
- * @skip: Number of entries to skip in slot
- */
-struct rhashtable_iter {
-	struct rhashtable *ht;
-	struct rhash_head *p;
-	struct rhlist_head *list;
-	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)
 {
 	return NULLS_MARKER(ht->p.nulls_base + hash);
@@ -376,11 +258,6 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
 }
 #endif /* CONFIG_PROVE_LOCKING */
 
-int rhashtable_init(struct rhashtable *ht,
-		    const struct rhashtable_params *params);
-int rhltable_init(struct rhltable *hlt,
-		  const struct rhashtable_params *params);
-
 void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
 			     struct rhash_head *obj);