Merge branch 'rhashtable_remove_shift'

Herbert Xu says:

====================
rhashtable: Kill redundant shift parameter

I was trying to squeeze bucket_table->rehash in by downsizing
bucket_table->size, only to find that my spot had been taken
over by bucket_table->shift.  These patches kill shift and makes
me feel better :)

v2 corrects the typo in the test_rhashtable changelog and also
notes the min_shift parameter in the tipc patch changelog.
====================

Acked-by: Thomas Graf <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: davem330

include/linux/rhashtable.h

@@ -51,7 +51,6 @@ struct rhash_head {
  * @size: Number of hash buckets
  * @rehash: Current bucket being rehashed
  * @hash_rnd: Random seed to fold into hash
- * @shift: Current size (1 << shift)
  * @locks_mask: Mask to apply before accessing locks[]
  * @locks: Array of spinlocks protecting individual buckets
  * @walkers: List of active walkers
@@ -63,7 +62,6 @@ struct bucket_table {
 	unsigned int		size;
 	unsigned int		rehash;
 	u32			hash_rnd;
-	u32			shift;
 	unsigned int		locks_mask;
 	spinlock_t		*locks;
 	struct list_head	walkers;
@@ -85,8 +83,8 @@ struct rhashtable;
  * @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_shift: Maximum number of shifts while expanding
- * @min_shift: Minimum number of shifts while shrinking
+ * @max_size: Maximum size while expanding
+ * @min_size: Minimum size while shrinking
  * @nulls_base: Base value to generate nulls marker
  * @locks_mul: Number of bucket locks to allocate per cpu (default: 128)
  * @hashfn: Function to hash key
@@ -97,8 +95,8 @@ struct rhashtable_params {
 	size_t			key_len;
 	size_t			key_offset;
 	size_t			head_offset;
-	size_t			max_shift;
-	size_t			min_shift;
+	unsigned int		max_size;
+	unsigned int		min_size;
 	u32			nulls_base;
 	size_t			locks_mul;
 	rht_hashfn_t		hashfn;

lib/rhashtable.c

@@ -27,7 +27,7 @@
 #include <linux/err.h>
 
 #define HASH_DEFAULT_SIZE	64UL
-#define HASH_MIN_SIZE		4UL
+#define HASH_MIN_SIZE		4U
 #define BUCKET_LOCKS_PER_CPU   128UL
 
 /* Base bits plus 1 bit for nulls marker */
@@ -162,7 +162,6 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
 		return NULL;
 
 	tbl->size = nbuckets;
-	tbl->shift = ilog2(nbuckets);
 
 	if (alloc_bucket_locks(ht, tbl) < 0) {
 		bucket_table_free(tbl);
@@ -189,7 +188,7 @@ static bool rht_grow_above_75(const struct rhashtable *ht,
 {
 	/* Expand table when exceeding 75% load */
 	return atomic_read(&ht->nelems) > (tbl->size / 4 * 3) &&
-	       (!ht->p.max_shift || tbl->shift < ht->p.max_shift);
+	       (!ht->p.max_size || tbl->size < ht->p.max_size);
 }
 
 /**
@@ -202,7 +201,7 @@ static bool rht_shrink_below_30(const struct rhashtable *ht,
 {
 	/* Shrink table beneath 30% load */
 	return atomic_read(&ht->nelems) < (tbl->size * 3 / 10) &&
-	       tbl->shift > ht->p.min_shift;
+	       tbl->size > ht->p.min_size;
 }
 
 static int rhashtable_rehash_one(struct rhashtable *ht, unsigned old_hash)
@@ -874,7 +873,7 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_stop);
 static size_t rounded_hashtable_size(struct rhashtable_params *params)
 {
 	return max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
-		   1UL << params->min_shift);
+		   (unsigned long)params->min_size);
 }
 
 /**
@@ -934,8 +933,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
 	if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT))
 		return -EINVAL;
 
-	params->min_shift = max_t(size_t, params->min_shift,
-				  ilog2(HASH_MIN_SIZE));
+	params->min_size = max(params->min_size, HASH_MIN_SIZE);
 
 	if (params->nelem_hint)
 		size = rounded_hashtable_size(params);

lib/test_rhashtable.c

@@ -201,7 +201,7 @@ static int __init test_rht_init(void)
 		.key_offset = offsetof(struct test_obj, value),
 		.key_len = sizeof(int),
 		.hashfn = jhash,
-		.max_shift = 1, /* we expand/shrink manually here */
+		.max_size = 2, /* we expand/shrink manually here */
 		.nulls_base = (3U << RHT_BASE_SHIFT),
 	};
 	int err;

net/netlink/af_netlink.c

@@ -3123,7 +3123,7 @@ static int __init netlink_proto_init(void)
 		.key_offset = offsetof(struct netlink_sock, portid),
 		.key_len = sizeof(u32), /* portid */
 		.hashfn = jhash,
-		.max_shift = 16, /* 64K */
+		.max_size = 65536,
 	};
 
 	if (err != 0)

net/tipc/socket.c

@@ -2286,8 +2286,8 @@ int tipc_sk_rht_init(struct net *net)
 		.key_offset = offsetof(struct tipc_sock, portid),
 		.key_len = sizeof(u32), /* portid */
 		.hashfn = jhash,
-		.max_shift = 20, /* 1M */
-		.min_shift = 8,  /* 256 */
+		.max_size = 1048576,
+		.min_size = 256,
 	};
 
 	return rhashtable_init(&tn->sk_rht, &rht_params);