Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Resizable, Scalable, Concurrent Hash Table |
| 3 | * |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 4 | * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> |
Thomas Graf | a5ec68e | 2015-02-05 02:03:32 +0100 | [diff] [blame] | 5 | * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 6 | * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> |
| 7 | * |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 8 | * Code partially derived from nft_hash |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 9 | * Rewritten with rehash code from br_multicast plus single list |
| 10 | * pointer as suggested by Josh Triplett |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 11 | * |
| 12 | * This program is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License version 2 as |
| 14 | * published by the Free Software Foundation. |
| 15 | */ |
| 16 | |
Herbert Xu | 07ee072 | 2015-05-15 11:30:47 +0800 | [diff] [blame] | 17 | #include <linux/atomic.h> |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 18 | #include <linux/kernel.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/log2.h> |
Eric Dumazet | 5beb5c9 | 2015-02-26 07:20:34 -0800 | [diff] [blame] | 21 | #include <linux/sched.h> |
Ingo Molnar | b2d0910 | 2017-02-04 01:27:20 +0100 | [diff] [blame] | 22 | #include <linux/rculist.h> |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 23 | #include <linux/slab.h> |
| 24 | #include <linux/vmalloc.h> |
| 25 | #include <linux/mm.h> |
Daniel Borkmann | 8754589 | 2014-12-10 16:33:11 +0100 | [diff] [blame] | 26 | #include <linux/jhash.h> |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 27 | #include <linux/random.h> |
| 28 | #include <linux/rhashtable.h> |
Stephen Rothwell | 61d7b09 | 2015-02-09 14:04:03 +1100 | [diff] [blame] | 29 | #include <linux/err.h> |
Hauke Mehrtens | 6d79541 | 2015-06-06 22:07:23 +0200 | [diff] [blame] | 30 | #include <linux/export.h> |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 31 | |
| 32 | #define HASH_DEFAULT_SIZE 64UL |
Herbert Xu | c2e213c | 2015-03-18 20:01:16 +1100 | [diff] [blame] | 33 | #define HASH_MIN_SIZE 4U |
Florian Westphal | 4cf0b35 | 2016-08-12 12:03:52 +0200 | [diff] [blame] | 34 | #define BUCKET_LOCKS_PER_CPU 32UL |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 35 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 36 | union nested_table { |
| 37 | union nested_table __rcu *table; |
| 38 | struct rhash_head __rcu *bucket; |
| 39 | }; |
| 40 | |
Herbert Xu | 988dfbd | 2015-03-10 09:27:55 +1100 | [diff] [blame] | 41 | static u32 head_hashfn(struct rhashtable *ht, |
Thomas Graf | 8d24c0b | 2015-01-02 23:00:14 +0100 | [diff] [blame] | 42 | const struct bucket_table *tbl, |
| 43 | const struct rhash_head *he) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 44 | { |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 45 | return rht_head_hashfn(ht, tbl, he, ht->p); |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 46 | } |
| 47 | |
Thomas Graf | a03eaec | 2015-02-05 02:03:34 +0100 | [diff] [blame] | 48 | #ifdef CONFIG_PROVE_LOCKING |
Thomas Graf | a03eaec | 2015-02-05 02:03:34 +0100 | [diff] [blame] | 49 | #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) |
Thomas Graf | a03eaec | 2015-02-05 02:03:34 +0100 | [diff] [blame] | 50 | |
| 51 | int lockdep_rht_mutex_is_held(struct rhashtable *ht) |
| 52 | { |
| 53 | return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1; |
| 54 | } |
| 55 | EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held); |
| 56 | |
| 57 | int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash) |
| 58 | { |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 59 | spinlock_t *lock = rht_bucket_lock(tbl, hash); |
Thomas Graf | a03eaec | 2015-02-05 02:03:34 +0100 | [diff] [blame] | 60 | |
| 61 | return (debug_locks) ? lockdep_is_held(lock) : 1; |
| 62 | } |
| 63 | EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held); |
| 64 | #else |
| 65 | #define ASSERT_RHT_MUTEX(HT) |
Thomas Graf | a03eaec | 2015-02-05 02:03:34 +0100 | [diff] [blame] | 66 | #endif |
| 67 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 68 | static void nested_table_free(union nested_table *ntbl, unsigned int size) |
| 69 | { |
| 70 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); |
| 71 | const unsigned int len = 1 << shift; |
| 72 | unsigned int i; |
| 73 | |
| 74 | ntbl = rcu_dereference_raw(ntbl->table); |
| 75 | if (!ntbl) |
| 76 | return; |
| 77 | |
| 78 | if (size > len) { |
| 79 | size >>= shift; |
| 80 | for (i = 0; i < len; i++) |
| 81 | nested_table_free(ntbl + i, size); |
| 82 | } |
| 83 | |
| 84 | kfree(ntbl); |
| 85 | } |
| 86 | |
| 87 | static void nested_bucket_table_free(const struct bucket_table *tbl) |
| 88 | { |
| 89 | unsigned int size = tbl->size >> tbl->nest; |
| 90 | unsigned int len = 1 << tbl->nest; |
| 91 | union nested_table *ntbl; |
| 92 | unsigned int i; |
| 93 | |
| 94 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); |
| 95 | |
| 96 | for (i = 0; i < len; i++) |
| 97 | nested_table_free(ntbl + i, size); |
| 98 | |
| 99 | kfree(ntbl); |
| 100 | } |
| 101 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 102 | static void bucket_table_free(const struct bucket_table *tbl) |
| 103 | { |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 104 | if (tbl->nest) |
| 105 | nested_bucket_table_free(tbl); |
| 106 | |
Tom Herbert | 64e0cd0 | 2017-12-04 10:31:45 -0800 | [diff] [blame] | 107 | free_bucket_spinlocks(tbl->locks); |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 108 | kvfree(tbl); |
| 109 | } |
| 110 | |
Herbert Xu | 9d901bc | 2015-03-14 13:57:23 +1100 | [diff] [blame] | 111 | static void bucket_table_free_rcu(struct rcu_head *head) |
| 112 | { |
| 113 | bucket_table_free(container_of(head, struct bucket_table, rcu)); |
| 114 | } |
| 115 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 116 | static union nested_table *nested_table_alloc(struct rhashtable *ht, |
| 117 | union nested_table __rcu **prev, |
NeilBrown | 5af68ef | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 118 | bool leaf) |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 119 | { |
| 120 | union nested_table *ntbl; |
| 121 | int i; |
| 122 | |
| 123 | ntbl = rcu_dereference(*prev); |
| 124 | if (ntbl) |
| 125 | return ntbl; |
| 126 | |
| 127 | ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC); |
| 128 | |
NeilBrown | 5af68ef | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 129 | if (ntbl && leaf) { |
| 130 | for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0]); i++) |
NeilBrown | 9b4f64a | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 131 | INIT_RHT_NULLS_HEAD(ntbl[i].bucket); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 132 | } |
| 133 | |
| 134 | rcu_assign_pointer(*prev, ntbl); |
| 135 | |
| 136 | return ntbl; |
| 137 | } |
| 138 | |
| 139 | static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, |
| 140 | size_t nbuckets, |
| 141 | gfp_t gfp) |
| 142 | { |
| 143 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); |
| 144 | struct bucket_table *tbl; |
| 145 | size_t size; |
| 146 | |
| 147 | if (nbuckets < (1 << (shift + 1))) |
| 148 | return NULL; |
| 149 | |
| 150 | size = sizeof(*tbl) + sizeof(tbl->buckets[0]); |
| 151 | |
| 152 | tbl = kzalloc(size, gfp); |
| 153 | if (!tbl) |
| 154 | return NULL; |
| 155 | |
| 156 | if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets, |
NeilBrown | 5af68ef | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 157 | false)) { |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 158 | kfree(tbl); |
| 159 | return NULL; |
| 160 | } |
| 161 | |
| 162 | tbl->nest = (ilog2(nbuckets) - 1) % shift + 1; |
| 163 | |
| 164 | return tbl; |
| 165 | } |
| 166 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 167 | static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, |
Herbert Xu | b9ecfda | 2015-03-24 00:50:27 +1100 | [diff] [blame] | 168 | size_t nbuckets, |
| 169 | gfp_t gfp) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 170 | { |
Daniel Borkmann | eb6d1ab | 2015-02-20 00:53:38 +0100 | [diff] [blame] | 171 | struct bucket_table *tbl = NULL; |
Tom Herbert | 64e0cd0 | 2017-12-04 10:31:45 -0800 | [diff] [blame] | 172 | size_t size, max_locks; |
Thomas Graf | f89bd6f | 2015-01-02 23:00:21 +0100 | [diff] [blame] | 173 | int i; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 174 | |
| 175 | size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); |
Davidlohr Bueso | 93f976b | 2018-08-21 22:01:45 -0700 | [diff] [blame] | 176 | tbl = kvzalloc(size, gfp); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 177 | |
| 178 | size = nbuckets; |
| 179 | |
Davidlohr Bueso | 2d22ecf | 2018-08-21 22:01:48 -0700 | [diff] [blame] | 180 | if (tbl == NULL && (gfp & ~__GFP_NOFAIL) != GFP_KERNEL) { |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 181 | tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); |
| 182 | nbuckets = 0; |
| 183 | } |
Davidlohr Bueso | 2d22ecf | 2018-08-21 22:01:48 -0700 | [diff] [blame] | 184 | |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 185 | if (tbl == NULL) |
| 186 | return NULL; |
| 187 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 188 | tbl->size = size; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 189 | |
Tom Herbert | 64e0cd0 | 2017-12-04 10:31:45 -0800 | [diff] [blame] | 190 | max_locks = size >> 1; |
| 191 | if (tbl->nest) |
| 192 | max_locks = min_t(size_t, max_locks, 1U << tbl->nest); |
| 193 | |
| 194 | if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask, max_locks, |
| 195 | ht->p.locks_mul, gfp) < 0) { |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 196 | bucket_table_free(tbl); |
| 197 | return NULL; |
| 198 | } |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 199 | |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 200 | rcu_head_init(&tbl->rcu); |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 201 | INIT_LIST_HEAD(&tbl->walkers); |
| 202 | |
Jason A. Donenfeld | d48ad08 | 2017-06-07 22:47:13 -0400 | [diff] [blame] | 203 | tbl->hash_rnd = get_random_u32(); |
Herbert Xu | 5269b53 | 2015-03-14 13:57:22 +1100 | [diff] [blame] | 204 | |
Thomas Graf | f89bd6f | 2015-01-02 23:00:21 +0100 | [diff] [blame] | 205 | for (i = 0; i < nbuckets; i++) |
NeilBrown | 9b4f64a | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 206 | INIT_RHT_NULLS_HEAD(tbl->buckets[i]); |
Thomas Graf | f89bd6f | 2015-01-02 23:00:21 +0100 | [diff] [blame] | 207 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 208 | return tbl; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 209 | } |
| 210 | |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 211 | static struct bucket_table *rhashtable_last_table(struct rhashtable *ht, |
| 212 | struct bucket_table *tbl) |
| 213 | { |
| 214 | struct bucket_table *new_tbl; |
| 215 | |
| 216 | do { |
| 217 | new_tbl = tbl; |
| 218 | tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
| 219 | } while (tbl); |
| 220 | |
| 221 | return new_tbl; |
| 222 | } |
| 223 | |
Thomas Graf | 299e5c3 | 2015-03-24 14:18:17 +0100 | [diff] [blame] | 224 | static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash) |
Thomas Graf | a5ec68e | 2015-02-05 02:03:32 +0100 | [diff] [blame] | 225 | { |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 226 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
NeilBrown | c069001 | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 227 | struct bucket_table *new_tbl = rhashtable_last_table(ht, old_tbl); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 228 | struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash); |
| 229 | int err = -EAGAIN; |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 230 | struct rhash_head *head, *next, *entry; |
| 231 | spinlock_t *new_bucket_lock; |
Thomas Graf | 299e5c3 | 2015-03-24 14:18:17 +0100 | [diff] [blame] | 232 | unsigned int new_hash; |
Thomas Graf | a5ec68e | 2015-02-05 02:03:32 +0100 | [diff] [blame] | 233 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 234 | if (new_tbl->nest) |
| 235 | goto out; |
| 236 | |
| 237 | err = -ENOENT; |
| 238 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 239 | rht_for_each(entry, old_tbl, old_hash) { |
| 240 | err = 0; |
| 241 | next = rht_dereference_bucket(entry->next, old_tbl, old_hash); |
Thomas Graf | a5ec68e | 2015-02-05 02:03:32 +0100 | [diff] [blame] | 242 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 243 | if (rht_is_a_nulls(next)) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 244 | break; |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 245 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 246 | pprev = &entry->next; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 247 | } |
| 248 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 249 | if (err) |
| 250 | goto out; |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 251 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 252 | new_hash = head_hashfn(ht, new_tbl, entry); |
Thomas Graf | a5ec68e | 2015-02-05 02:03:32 +0100 | [diff] [blame] | 253 | |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 254 | new_bucket_lock = rht_bucket_lock(new_tbl, new_hash); |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 255 | |
Herbert Xu | 8f2484b | 2015-03-14 13:57:21 +1100 | [diff] [blame] | 256 | spin_lock_nested(new_bucket_lock, SINGLE_DEPTH_NESTING); |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 257 | head = rht_dereference_bucket(new_tbl->buckets[new_hash], |
| 258 | new_tbl, new_hash); |
| 259 | |
Dmitriy Vyukov | 7def0f9 | 2015-09-22 10:51:52 +0200 | [diff] [blame] | 260 | RCU_INIT_POINTER(entry->next, head); |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 261 | |
| 262 | rcu_assign_pointer(new_tbl->buckets[new_hash], entry); |
| 263 | spin_unlock(new_bucket_lock); |
| 264 | |
| 265 | rcu_assign_pointer(*pprev, next); |
| 266 | |
| 267 | out: |
| 268 | return err; |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 269 | } |
| 270 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 271 | static int rhashtable_rehash_chain(struct rhashtable *ht, |
Thomas Graf | 299e5c3 | 2015-03-24 14:18:17 +0100 | [diff] [blame] | 272 | unsigned int old_hash) |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 273 | { |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 274 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
| 275 | spinlock_t *old_bucket_lock; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 276 | int err; |
Thomas Graf | 7cd10db | 2015-02-05 02:03:35 +0100 | [diff] [blame] | 277 | |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 278 | old_bucket_lock = rht_bucket_lock(old_tbl, old_hash); |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 279 | |
| 280 | spin_lock_bh(old_bucket_lock); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 281 | while (!(err = rhashtable_rehash_one(ht, old_hash))) |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 282 | ; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 283 | |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 284 | if (err == -ENOENT) |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 285 | err = 0; |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 286 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 287 | spin_unlock_bh(old_bucket_lock); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 288 | |
| 289 | return err; |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 290 | } |
| 291 | |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 292 | static int rhashtable_rehash_attach(struct rhashtable *ht, |
| 293 | struct bucket_table *old_tbl, |
| 294 | struct bucket_table *new_tbl) |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 295 | { |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 296 | /* Make insertions go into the new, empty table right away. Deletions |
| 297 | * and lookups will be attempted in both tables until we synchronize. |
NeilBrown | 0ad6644 | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 298 | * As cmpxchg() provides strong barriers, we do not need |
| 299 | * rcu_assign_pointer(). |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 300 | */ |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 301 | |
NeilBrown | 0ad6644 | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 302 | if (cmpxchg(&old_tbl->future_tbl, NULL, new_tbl) != NULL) |
| 303 | return -EEXIST; |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 304 | |
| 305 | return 0; |
| 306 | } |
| 307 | |
| 308 | static int rhashtable_rehash_table(struct rhashtable *ht) |
| 309 | { |
| 310 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
| 311 | struct bucket_table *new_tbl; |
| 312 | struct rhashtable_walker *walker; |
Thomas Graf | 299e5c3 | 2015-03-24 14:18:17 +0100 | [diff] [blame] | 313 | unsigned int old_hash; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 314 | int err; |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 315 | |
| 316 | new_tbl = rht_dereference(old_tbl->future_tbl, ht); |
| 317 | if (!new_tbl) |
| 318 | return 0; |
| 319 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 320 | for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { |
| 321 | err = rhashtable_rehash_chain(ht, old_hash); |
| 322 | if (err) |
| 323 | return err; |
Eric Dumazet | ae6da1f | 2018-03-31 12:58:48 -0700 | [diff] [blame] | 324 | cond_resched(); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 325 | } |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 326 | |
| 327 | /* Publish the new table pointer. */ |
| 328 | rcu_assign_pointer(ht->tbl, new_tbl); |
| 329 | |
Herbert Xu | ba7c95e | 2015-03-24 09:53:17 +1100 | [diff] [blame] | 330 | spin_lock(&ht->lock); |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 331 | list_for_each_entry(walker, &old_tbl->walkers, list) |
| 332 | walker->tbl = NULL; |
| 333 | |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 334 | /* Wait for readers. All new readers will see the new |
| 335 | * table, and thus no references to the old table will |
| 336 | * remain. |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 337 | * We do this inside the locked region so that |
| 338 | * rhashtable_walk_stop() can use rcu_head_after_call_rcu() |
| 339 | * to check if it should not re-link the table. |
Herbert Xu | aa34a6cb0 | 2015-03-11 09:43:48 +1100 | [diff] [blame] | 340 | */ |
Herbert Xu | 9d901bc | 2015-03-14 13:57:23 +1100 | [diff] [blame] | 341 | call_rcu(&old_tbl->rcu, bucket_table_free_rcu); |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 342 | spin_unlock(&ht->lock); |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 343 | |
| 344 | return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 345 | } |
| 346 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 347 | static int rhashtable_rehash_alloc(struct rhashtable *ht, |
| 348 | struct bucket_table *old_tbl, |
| 349 | unsigned int size) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 350 | { |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 351 | struct bucket_table *new_tbl; |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 352 | int err; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 353 | |
| 354 | ASSERT_RHT_MUTEX(ht); |
| 355 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 356 | new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 357 | if (new_tbl == NULL) |
| 358 | return -ENOMEM; |
| 359 | |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 360 | err = rhashtable_rehash_attach(ht, old_tbl, new_tbl); |
| 361 | if (err) |
| 362 | bucket_table_free(new_tbl); |
| 363 | |
| 364 | return err; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 365 | } |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 366 | |
| 367 | /** |
| 368 | * rhashtable_shrink - Shrink hash table while allowing concurrent lookups |
| 369 | * @ht: the hash table to shrink |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 370 | * |
Herbert Xu | 18093d1 | 2015-03-24 00:50:25 +1100 | [diff] [blame] | 371 | * This function shrinks the hash table to fit, i.e., the smallest |
| 372 | * size would not cause it to expand right away automatically. |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 373 | * |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 374 | * The caller must ensure that no concurrent resizing occurs by holding |
| 375 | * ht->mutex. |
| 376 | * |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 377 | * The caller must ensure that no concurrent table mutations take place. |
| 378 | * It is however valid to have concurrent lookups if they are RCU protected. |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 379 | * |
| 380 | * It is valid to have concurrent insertions and deletions protected by per |
| 381 | * bucket locks or concurrent RCU protected lookups and traversals. |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 382 | */ |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 383 | static int rhashtable_shrink(struct rhashtable *ht) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 384 | { |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 385 | struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); |
Vegard Nossum | 1231195 | 2016-08-12 20:10:44 +0200 | [diff] [blame] | 386 | unsigned int nelems = atomic_read(&ht->nelems); |
| 387 | unsigned int size = 0; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 388 | |
Vegard Nossum | 1231195 | 2016-08-12 20:10:44 +0200 | [diff] [blame] | 389 | if (nelems) |
| 390 | size = roundup_pow_of_two(nelems * 3 / 2); |
Herbert Xu | 18093d1 | 2015-03-24 00:50:25 +1100 | [diff] [blame] | 391 | if (size < ht->p.min_size) |
| 392 | size = ht->p.min_size; |
| 393 | |
| 394 | if (old_tbl->size <= size) |
| 395 | return 0; |
| 396 | |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 397 | if (rht_dereference(old_tbl->future_tbl, ht)) |
| 398 | return -EEXIST; |
| 399 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 400 | return rhashtable_rehash_alloc(ht, old_tbl, size); |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 401 | } |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 402 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 403 | static void rht_deferred_worker(struct work_struct *work) |
| 404 | { |
| 405 | struct rhashtable *ht; |
| 406 | struct bucket_table *tbl; |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 407 | int err = 0; |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 408 | |
Ying Xue | 57699a4 | 2015-01-16 11:13:09 +0800 | [diff] [blame] | 409 | ht = container_of(work, struct rhashtable, run_work); |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 410 | mutex_lock(&ht->mutex); |
Herbert Xu | 28134a5 | 2015-02-04 07:33:22 +1100 | [diff] [blame] | 411 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 412 | tbl = rht_dereference(ht->tbl, ht); |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 413 | tbl = rhashtable_last_table(ht, tbl); |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 414 | |
Daniel Borkmann | a5b6846 | 2015-03-12 15:28:40 +0100 | [diff] [blame] | 415 | if (rht_grow_above_75(ht, tbl)) |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 416 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2); |
Thomas Graf | b5e2c15 | 2015-03-24 20:42:19 +0000 | [diff] [blame] | 417 | else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl)) |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 418 | err = rhashtable_shrink(ht); |
| 419 | else if (tbl->nest) |
| 420 | err = rhashtable_rehash_alloc(ht, tbl, tbl->size); |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 421 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 422 | if (!err) |
| 423 | err = rhashtable_rehash_table(ht); |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 424 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 425 | mutex_unlock(&ht->mutex); |
Herbert Xu | b824478 | 2015-03-24 00:50:26 +1100 | [diff] [blame] | 426 | |
| 427 | if (err) |
| 428 | schedule_work(&ht->run_work); |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 429 | } |
| 430 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 431 | static int rhashtable_insert_rehash(struct rhashtable *ht, |
| 432 | struct bucket_table *tbl) |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 433 | { |
| 434 | struct bucket_table *old_tbl; |
| 435 | struct bucket_table *new_tbl; |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 436 | unsigned int size; |
| 437 | int err; |
| 438 | |
| 439 | old_tbl = rht_dereference_rcu(ht->tbl, ht); |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 440 | |
| 441 | size = tbl->size; |
| 442 | |
Herbert Xu | 3cf9222 | 2015-12-03 20:41:29 +0800 | [diff] [blame] | 443 | err = -EBUSY; |
| 444 | |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 445 | if (rht_grow_above_75(ht, tbl)) |
| 446 | size *= 2; |
Thomas Graf | a87b9eb | 2015-04-22 09:41:46 +0200 | [diff] [blame] | 447 | /* Do not schedule more than one rehash */ |
| 448 | else if (old_tbl != tbl) |
Herbert Xu | 3cf9222 | 2015-12-03 20:41:29 +0800 | [diff] [blame] | 449 | goto fail; |
| 450 | |
| 451 | err = -ENOMEM; |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 452 | |
Davidlohr Bueso | 93f976b | 2018-08-21 22:01:45 -0700 | [diff] [blame] | 453 | new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC | __GFP_NOWARN); |
Herbert Xu | 3cf9222 | 2015-12-03 20:41:29 +0800 | [diff] [blame] | 454 | if (new_tbl == NULL) |
| 455 | goto fail; |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 456 | |
| 457 | err = rhashtable_rehash_attach(ht, tbl, new_tbl); |
| 458 | if (err) { |
| 459 | bucket_table_free(new_tbl); |
| 460 | if (err == -EEXIST) |
| 461 | err = 0; |
| 462 | } else |
| 463 | schedule_work(&ht->run_work); |
| 464 | |
| 465 | return err; |
Herbert Xu | 3cf9222 | 2015-12-03 20:41:29 +0800 | [diff] [blame] | 466 | |
| 467 | fail: |
| 468 | /* Do not fail the insert if someone else did a rehash. */ |
NeilBrown | c069001 | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 469 | if (likely(rcu_access_pointer(tbl->future_tbl))) |
Herbert Xu | 3cf9222 | 2015-12-03 20:41:29 +0800 | [diff] [blame] | 470 | return 0; |
| 471 | |
| 472 | /* Schedule async rehash to retry allocation in process context. */ |
| 473 | if (err == -ENOMEM) |
| 474 | schedule_work(&ht->run_work); |
| 475 | |
| 476 | return err; |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 477 | } |
Herbert Xu | ccd57b1 | 2015-03-24 00:50:28 +1100 | [diff] [blame] | 478 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 479 | static void *rhashtable_lookup_one(struct rhashtable *ht, |
| 480 | struct bucket_table *tbl, unsigned int hash, |
| 481 | const void *key, struct rhash_head *obj) |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 482 | { |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 483 | struct rhashtable_compare_arg arg = { |
| 484 | .ht = ht, |
| 485 | .key = key, |
| 486 | }; |
| 487 | struct rhash_head __rcu **pprev; |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 488 | struct rhash_head *head; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 489 | int elasticity; |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 490 | |
Florian Westphal | 5f8ddea | 2017-04-16 02:55:09 +0200 | [diff] [blame] | 491 | elasticity = RHT_ELASTICITY; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 492 | pprev = rht_bucket_var(tbl, hash); |
| 493 | rht_for_each_continue(head, *pprev, tbl, hash) { |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 494 | struct rhlist_head *list; |
| 495 | struct rhlist_head *plist; |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 496 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 497 | elasticity--; |
| 498 | if (!key || |
| 499 | (ht->p.obj_cmpfn ? |
| 500 | ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : |
Paul Blakey | d3dcf8e | 2018-03-04 17:29:48 +0200 | [diff] [blame] | 501 | rhashtable_compare(&arg, rht_obj(ht, head)))) { |
| 502 | pprev = &head->next; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 503 | continue; |
Paul Blakey | d3dcf8e | 2018-03-04 17:29:48 +0200 | [diff] [blame] | 504 | } |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 505 | |
| 506 | if (!ht->rhlist) |
| 507 | return rht_obj(ht, head); |
| 508 | |
| 509 | list = container_of(obj, struct rhlist_head, rhead); |
| 510 | plist = container_of(head, struct rhlist_head, rhead); |
| 511 | |
| 512 | RCU_INIT_POINTER(list->next, plist); |
| 513 | head = rht_dereference_bucket(head->next, tbl, hash); |
| 514 | RCU_INIT_POINTER(list->rhead.next, head); |
| 515 | rcu_assign_pointer(*pprev, obj); |
| 516 | |
| 517 | return NULL; |
Pablo Neira Ayuso | 5ca8cc5 | 2016-08-24 12:31:31 +0200 | [diff] [blame] | 518 | } |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 519 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 520 | if (elasticity <= 0) |
| 521 | return ERR_PTR(-EAGAIN); |
| 522 | |
| 523 | return ERR_PTR(-ENOENT); |
| 524 | } |
| 525 | |
| 526 | static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, |
| 527 | struct bucket_table *tbl, |
| 528 | unsigned int hash, |
| 529 | struct rhash_head *obj, |
| 530 | void *data) |
| 531 | { |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 532 | struct rhash_head __rcu **pprev; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 533 | struct bucket_table *new_tbl; |
| 534 | struct rhash_head *head; |
| 535 | |
| 536 | if (!IS_ERR_OR_NULL(data)) |
| 537 | return ERR_PTR(-EEXIST); |
| 538 | |
| 539 | if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) |
| 540 | return ERR_CAST(data); |
| 541 | |
NeilBrown | c069001 | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 542 | new_tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 543 | if (new_tbl) |
| 544 | return new_tbl; |
| 545 | |
| 546 | if (PTR_ERR(data) != -ENOENT) |
| 547 | return ERR_CAST(data); |
| 548 | |
Herbert Xu | 07ee072 | 2015-05-15 11:30:47 +0800 | [diff] [blame] | 549 | if (unlikely(rht_grow_above_max(ht, tbl))) |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 550 | return ERR_PTR(-E2BIG); |
Herbert Xu | 07ee072 | 2015-05-15 11:30:47 +0800 | [diff] [blame] | 551 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 552 | if (unlikely(rht_grow_above_100(ht, tbl))) |
| 553 | return ERR_PTR(-EAGAIN); |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 554 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 555 | pprev = rht_bucket_insert(ht, tbl, hash); |
| 556 | if (!pprev) |
| 557 | return ERR_PTR(-ENOMEM); |
| 558 | |
| 559 | head = rht_dereference_bucket(*pprev, tbl, hash); |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 560 | |
| 561 | RCU_INIT_POINTER(obj->next, head); |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 562 | if (ht->rhlist) { |
| 563 | struct rhlist_head *list; |
| 564 | |
| 565 | list = container_of(obj, struct rhlist_head, rhead); |
| 566 | RCU_INIT_POINTER(list->next, NULL); |
| 567 | } |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 568 | |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 569 | rcu_assign_pointer(*pprev, obj); |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 570 | |
| 571 | atomic_inc(&ht->nelems); |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 572 | if (rht_grow_above_75(ht, tbl)) |
| 573 | schedule_work(&ht->run_work); |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 574 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 575 | return NULL; |
| 576 | } |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 577 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 578 | static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, |
| 579 | struct rhash_head *obj) |
| 580 | { |
| 581 | struct bucket_table *new_tbl; |
| 582 | struct bucket_table *tbl; |
| 583 | unsigned int hash; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 584 | void *data; |
| 585 | |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 586 | new_tbl = rcu_dereference(ht->tbl); |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 587 | |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 588 | do { |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 589 | tbl = new_tbl; |
| 590 | hash = rht_head_hashfn(ht, tbl, obj, ht->p); |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 591 | spin_lock_bh(rht_bucket_lock(tbl, hash)); |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 592 | |
| 593 | data = rhashtable_lookup_one(ht, tbl, hash, key, obj); |
| 594 | new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); |
| 595 | if (PTR_ERR(new_tbl) != -EEXIST) |
| 596 | data = ERR_CAST(new_tbl); |
| 597 | |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 598 | spin_unlock_bh(rht_bucket_lock(tbl, hash)); |
| 599 | } while (!IS_ERR_OR_NULL(new_tbl)); |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 600 | |
| 601 | if (PTR_ERR(data) == -EAGAIN) |
| 602 | data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: |
| 603 | -EAGAIN); |
| 604 | |
| 605 | return data; |
| 606 | } |
| 607 | |
| 608 | void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, |
| 609 | struct rhash_head *obj) |
| 610 | { |
| 611 | void *data; |
| 612 | |
| 613 | do { |
| 614 | rcu_read_lock(); |
| 615 | data = rhashtable_try_insert(ht, key, obj); |
| 616 | rcu_read_unlock(); |
| 617 | } while (PTR_ERR(data) == -EAGAIN); |
| 618 | |
| 619 | return data; |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 620 | } |
| 621 | EXPORT_SYMBOL_GPL(rhashtable_insert_slow); |
| 622 | |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 623 | /** |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 624 | * rhashtable_walk_enter - Initialise an iterator |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 625 | * @ht: Table to walk over |
| 626 | * @iter: Hash table Iterator |
| 627 | * |
| 628 | * This function prepares a hash table walk. |
| 629 | * |
| 630 | * Note that if you restart a walk after rhashtable_walk_stop you |
| 631 | * may see the same object twice. Also, you may miss objects if |
| 632 | * there are removals in between rhashtable_walk_stop and the next |
| 633 | * call to rhashtable_walk_start. |
| 634 | * |
| 635 | * For a completely stable walk you should construct your own data |
| 636 | * structure outside the hash table. |
| 637 | * |
NeilBrown | 82266e9 | 2018-04-24 08:29:13 +1000 | [diff] [blame] | 638 | * This function may be called from any process context, including |
| 639 | * non-preemptable context, but cannot be called from softirq or |
| 640 | * hardirq context. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 641 | * |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 642 | * You must call rhashtable_walk_exit after this function returns. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 643 | */ |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 644 | void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 645 | { |
| 646 | iter->ht = ht; |
| 647 | iter->p = NULL; |
| 648 | iter->slot = 0; |
| 649 | iter->skip = 0; |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 650 | iter->end_of_table = 0; |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 651 | |
Herbert Xu | c6ff526 | 2015-12-16 16:45:54 +0800 | [diff] [blame] | 652 | spin_lock(&ht->lock); |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 653 | iter->walker.tbl = |
Herbert Xu | 179ccc0 | 2015-12-19 10:45:28 +0800 | [diff] [blame] | 654 | rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 655 | list_add(&iter->walker.list, &iter->walker.tbl->walkers); |
Herbert Xu | c6ff526 | 2015-12-16 16:45:54 +0800 | [diff] [blame] | 656 | spin_unlock(&ht->lock); |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 657 | } |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 658 | EXPORT_SYMBOL_GPL(rhashtable_walk_enter); |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 659 | |
| 660 | /** |
| 661 | * rhashtable_walk_exit - Free an iterator |
| 662 | * @iter: Hash table Iterator |
| 663 | * |
Herbert Xu | 6c4128f | 2019-02-14 22:03:27 +0800 | [diff] [blame] | 664 | * This function frees resources allocated by rhashtable_walk_enter. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 665 | */ |
| 666 | void rhashtable_walk_exit(struct rhashtable_iter *iter) |
| 667 | { |
Herbert Xu | c6ff526 | 2015-12-16 16:45:54 +0800 | [diff] [blame] | 668 | spin_lock(&iter->ht->lock); |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 669 | if (iter->walker.tbl) |
| 670 | list_del(&iter->walker.list); |
Herbert Xu | c6ff526 | 2015-12-16 16:45:54 +0800 | [diff] [blame] | 671 | spin_unlock(&iter->ht->lock); |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 672 | } |
| 673 | EXPORT_SYMBOL_GPL(rhashtable_walk_exit); |
| 674 | |
| 675 | /** |
Tom Herbert | 97a6ec4 | 2017-12-04 10:31:41 -0800 | [diff] [blame] | 676 | * rhashtable_walk_start_check - Start a hash table walk |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 677 | * @iter: Hash table iterator |
| 678 | * |
Andreas Gruenbacher | 0647169 | 2017-09-19 12:41:37 +0200 | [diff] [blame] | 679 | * Start a hash table walk at the current iterator position. Note that we take |
| 680 | * the RCU lock in all cases including when we return an error. So you must |
| 681 | * always call rhashtable_walk_stop to clean up. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 682 | * |
| 683 | * Returns zero if successful. |
| 684 | * |
| 685 | * Returns -EAGAIN if resize event occured. Note that the iterator |
| 686 | * will rewind back to the beginning and you may use it immediately |
| 687 | * by calling rhashtable_walk_next. |
Tom Herbert | 97a6ec4 | 2017-12-04 10:31:41 -0800 | [diff] [blame] | 688 | * |
| 689 | * rhashtable_walk_start is defined as an inline variant that returns |
| 690 | * void. This is preferred in cases where the caller would ignore |
| 691 | * resize events and always continue. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 692 | */ |
Tom Herbert | 97a6ec4 | 2017-12-04 10:31:41 -0800 | [diff] [blame] | 693 | int rhashtable_walk_start_check(struct rhashtable_iter *iter) |
Thomas Graf | db4374f | 2015-03-16 10:42:27 +0100 | [diff] [blame] | 694 | __acquires(RCU) |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 695 | { |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 696 | struct rhashtable *ht = iter->ht; |
NeilBrown | 5d240a8 | 2018-04-24 08:29:13 +1000 | [diff] [blame] | 697 | bool rhlist = ht->rhlist; |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 698 | |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 699 | rcu_read_lock(); |
| 700 | |
Herbert Xu | c6ff526 | 2015-12-16 16:45:54 +0800 | [diff] [blame] | 701 | spin_lock(&ht->lock); |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 702 | if (iter->walker.tbl) |
| 703 | list_del(&iter->walker.list); |
Herbert Xu | c6ff526 | 2015-12-16 16:45:54 +0800 | [diff] [blame] | 704 | spin_unlock(&ht->lock); |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 705 | |
NeilBrown | 5d240a8 | 2018-04-24 08:29:13 +1000 | [diff] [blame] | 706 | if (iter->end_of_table) |
| 707 | return 0; |
| 708 | if (!iter->walker.tbl) { |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 709 | iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); |
NeilBrown | b41cc04 | 2018-04-24 08:29:13 +1000 | [diff] [blame] | 710 | iter->slot = 0; |
| 711 | iter->skip = 0; |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 712 | return -EAGAIN; |
| 713 | } |
| 714 | |
NeilBrown | 5d240a8 | 2018-04-24 08:29:13 +1000 | [diff] [blame] | 715 | if (iter->p && !rhlist) { |
| 716 | /* |
| 717 | * We need to validate that 'p' is still in the table, and |
| 718 | * if so, update 'skip' |
| 719 | */ |
| 720 | struct rhash_head *p; |
| 721 | int skip = 0; |
| 722 | rht_for_each_rcu(p, iter->walker.tbl, iter->slot) { |
| 723 | skip++; |
| 724 | if (p == iter->p) { |
| 725 | iter->skip = skip; |
| 726 | goto found; |
| 727 | } |
| 728 | } |
| 729 | iter->p = NULL; |
| 730 | } else if (iter->p && rhlist) { |
| 731 | /* Need to validate that 'list' is still in the table, and |
| 732 | * if so, update 'skip' and 'p'. |
| 733 | */ |
| 734 | struct rhash_head *p; |
| 735 | struct rhlist_head *list; |
| 736 | int skip = 0; |
| 737 | rht_for_each_rcu(p, iter->walker.tbl, iter->slot) { |
| 738 | for (list = container_of(p, struct rhlist_head, rhead); |
| 739 | list; |
| 740 | list = rcu_dereference(list->next)) { |
| 741 | skip++; |
| 742 | if (list == iter->list) { |
| 743 | iter->p = p; |
Rishabh Bhatnagar | c643ecf | 2018-07-02 09:35:34 -0700 | [diff] [blame] | 744 | iter->skip = skip; |
NeilBrown | 5d240a8 | 2018-04-24 08:29:13 +1000 | [diff] [blame] | 745 | goto found; |
| 746 | } |
| 747 | } |
| 748 | } |
| 749 | iter->p = NULL; |
| 750 | } |
| 751 | found: |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 752 | return 0; |
| 753 | } |
Tom Herbert | 97a6ec4 | 2017-12-04 10:31:41 -0800 | [diff] [blame] | 754 | EXPORT_SYMBOL_GPL(rhashtable_walk_start_check); |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 755 | |
| 756 | /** |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 757 | * __rhashtable_walk_find_next - Find the next element in a table (or the first |
| 758 | * one in case of a new walk). |
| 759 | * |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 760 | * @iter: Hash table iterator |
| 761 | * |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 762 | * Returns the found object or NULL when the end of the table is reached. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 763 | * |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 764 | * Returns -EAGAIN if resize event occurred. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 765 | */ |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 766 | static void *__rhashtable_walk_find_next(struct rhashtable_iter *iter) |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 767 | { |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 768 | struct bucket_table *tbl = iter->walker.tbl; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 769 | struct rhlist_head *list = iter->list; |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 770 | struct rhashtable *ht = iter->ht; |
| 771 | struct rhash_head *p = iter->p; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 772 | bool rhlist = ht->rhlist; |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 773 | |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 774 | if (!tbl) |
| 775 | return NULL; |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 776 | |
| 777 | for (; iter->slot < tbl->size; iter->slot++) { |
| 778 | int skip = iter->skip; |
| 779 | |
| 780 | rht_for_each_rcu(p, tbl, iter->slot) { |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 781 | if (rhlist) { |
| 782 | list = container_of(p, struct rhlist_head, |
| 783 | rhead); |
| 784 | do { |
| 785 | if (!skip) |
| 786 | goto next; |
| 787 | skip--; |
| 788 | list = rcu_dereference(list->next); |
| 789 | } while (list); |
| 790 | |
| 791 | continue; |
| 792 | } |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 793 | if (!skip) |
| 794 | break; |
| 795 | skip--; |
| 796 | } |
| 797 | |
| 798 | next: |
| 799 | if (!rht_is_a_nulls(p)) { |
| 800 | iter->skip++; |
| 801 | iter->p = p; |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 802 | iter->list = list; |
| 803 | return rht_obj(ht, rhlist ? &list->rhead : p); |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 804 | } |
| 805 | |
| 806 | iter->skip = 0; |
| 807 | } |
| 808 | |
Phil Sutter | 142b942 | 2015-07-06 15:51:20 +0200 | [diff] [blame] | 809 | iter->p = NULL; |
| 810 | |
Herbert Xu | d88252f | 2015-03-24 00:50:19 +1100 | [diff] [blame] | 811 | /* Ensure we see any new tables. */ |
| 812 | smp_rmb(); |
| 813 | |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 814 | iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); |
| 815 | if (iter->walker.tbl) { |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 816 | iter->slot = 0; |
| 817 | iter->skip = 0; |
| 818 | return ERR_PTR(-EAGAIN); |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 819 | } else { |
| 820 | iter->end_of_table = true; |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 821 | } |
| 822 | |
Thomas Graf | c936a79 | 2015-05-05 02:22:53 +0200 | [diff] [blame] | 823 | return NULL; |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 824 | } |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 825 | |
| 826 | /** |
| 827 | * rhashtable_walk_next - Return the next object and advance the iterator |
| 828 | * @iter: Hash table iterator |
| 829 | * |
| 830 | * Note that you must call rhashtable_walk_stop when you are finished |
| 831 | * with the walk. |
| 832 | * |
| 833 | * Returns the next object or NULL when the end of the table is reached. |
| 834 | * |
| 835 | * Returns -EAGAIN if resize event occurred. Note that the iterator |
| 836 | * will rewind back to the beginning and you may continue to use it. |
| 837 | */ |
| 838 | void *rhashtable_walk_next(struct rhashtable_iter *iter) |
| 839 | { |
| 840 | struct rhlist_head *list = iter->list; |
| 841 | struct rhashtable *ht = iter->ht; |
| 842 | struct rhash_head *p = iter->p; |
| 843 | bool rhlist = ht->rhlist; |
| 844 | |
| 845 | if (p) { |
| 846 | if (!rhlist || !(list = rcu_dereference(list->next))) { |
| 847 | p = rcu_dereference(p->next); |
| 848 | list = container_of(p, struct rhlist_head, rhead); |
| 849 | } |
| 850 | if (!rht_is_a_nulls(p)) { |
| 851 | iter->skip++; |
| 852 | iter->p = p; |
| 853 | iter->list = list; |
| 854 | return rht_obj(ht, rhlist ? &list->rhead : p); |
| 855 | } |
| 856 | |
| 857 | /* At the end of this slot, switch to next one and then find |
| 858 | * next entry from that point. |
| 859 | */ |
| 860 | iter->skip = 0; |
| 861 | iter->slot++; |
| 862 | } |
| 863 | |
| 864 | return __rhashtable_walk_find_next(iter); |
| 865 | } |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 866 | EXPORT_SYMBOL_GPL(rhashtable_walk_next); |
| 867 | |
| 868 | /** |
Tom Herbert | 2db54b4 | 2017-12-04 10:31:42 -0800 | [diff] [blame] | 869 | * rhashtable_walk_peek - Return the next object but don't advance the iterator |
| 870 | * @iter: Hash table iterator |
| 871 | * |
| 872 | * Returns the next object or NULL when the end of the table is reached. |
| 873 | * |
| 874 | * Returns -EAGAIN if resize event occurred. Note that the iterator |
| 875 | * will rewind back to the beginning and you may continue to use it. |
| 876 | */ |
| 877 | void *rhashtable_walk_peek(struct rhashtable_iter *iter) |
| 878 | { |
| 879 | struct rhlist_head *list = iter->list; |
| 880 | struct rhashtable *ht = iter->ht; |
| 881 | struct rhash_head *p = iter->p; |
| 882 | |
| 883 | if (p) |
| 884 | return rht_obj(ht, ht->rhlist ? &list->rhead : p); |
| 885 | |
| 886 | /* No object found in current iter, find next one in the table. */ |
| 887 | |
| 888 | if (iter->skip) { |
| 889 | /* A nonzero skip value points to the next entry in the table |
| 890 | * beyond that last one that was found. Decrement skip so |
| 891 | * we find the current value. __rhashtable_walk_find_next |
| 892 | * will restore the original value of skip assuming that |
| 893 | * the table hasn't changed. |
| 894 | */ |
| 895 | iter->skip--; |
| 896 | } |
| 897 | |
| 898 | return __rhashtable_walk_find_next(iter); |
| 899 | } |
| 900 | EXPORT_SYMBOL_GPL(rhashtable_walk_peek); |
| 901 | |
| 902 | /** |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 903 | * rhashtable_walk_stop - Finish a hash table walk |
| 904 | * @iter: Hash table iterator |
| 905 | * |
Andreas Gruenbacher | 0647169 | 2017-09-19 12:41:37 +0200 | [diff] [blame] | 906 | * Finish a hash table walk. Does not reset the iterator to the start of the |
| 907 | * hash table. |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 908 | */ |
| 909 | void rhashtable_walk_stop(struct rhashtable_iter *iter) |
Thomas Graf | db4374f | 2015-03-16 10:42:27 +0100 | [diff] [blame] | 910 | __releases(RCU) |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 911 | { |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 912 | struct rhashtable *ht; |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 913 | struct bucket_table *tbl = iter->walker.tbl; |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 914 | |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 915 | if (!tbl) |
Herbert Xu | 963ecbd | 2015-03-15 21:12:04 +1100 | [diff] [blame] | 916 | goto out; |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 917 | |
| 918 | ht = iter->ht; |
| 919 | |
Herbert Xu | ba7c95e | 2015-03-24 09:53:17 +1100 | [diff] [blame] | 920 | spin_lock(&ht->lock); |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 921 | if (rcu_head_after_call_rcu(&tbl->rcu, bucket_table_free_rcu)) |
| 922 | /* This bucket table is being freed, don't re-link it. */ |
Herbert Xu | 246779d | 2016-08-18 16:50:56 +0800 | [diff] [blame] | 923 | iter->walker.tbl = NULL; |
NeilBrown | 4feb7c7 | 2019-03-21 14:42:40 +1100 | [diff] [blame^] | 924 | else |
| 925 | list_add(&iter->walker.list, &tbl->walkers); |
Herbert Xu | ba7c95e | 2015-03-24 09:53:17 +1100 | [diff] [blame] | 926 | spin_unlock(&ht->lock); |
Herbert Xu | eddee5ba | 2015-03-14 13:57:20 +1100 | [diff] [blame] | 927 | |
Herbert Xu | 963ecbd | 2015-03-15 21:12:04 +1100 | [diff] [blame] | 928 | out: |
| 929 | rcu_read_unlock(); |
Herbert Xu | f2dba9c | 2015-02-04 07:33:23 +1100 | [diff] [blame] | 930 | } |
| 931 | EXPORT_SYMBOL_GPL(rhashtable_walk_stop); |
| 932 | |
Herbert Xu | 488fb86e | 2015-03-20 21:56:59 +1100 | [diff] [blame] | 933 | static size_t rounded_hashtable_size(const struct rhashtable_params *params) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 934 | { |
Davidlohr Bueso | 107d01f | 2018-07-16 13:26:13 -0700 | [diff] [blame] | 935 | size_t retsize; |
| 936 | |
| 937 | if (params->nelem_hint) |
| 938 | retsize = max(roundup_pow_of_two(params->nelem_hint * 4 / 3), |
| 939 | (unsigned long)params->min_size); |
| 940 | else |
| 941 | retsize = max(HASH_DEFAULT_SIZE, |
| 942 | (unsigned long)params->min_size); |
| 943 | |
| 944 | return retsize; |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 945 | } |
| 946 | |
Herbert Xu | 31ccde2 | 2015-03-24 00:50:21 +1100 | [diff] [blame] | 947 | static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) |
| 948 | { |
| 949 | return jhash2(key, length, seed); |
| 950 | } |
| 951 | |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 952 | /** |
| 953 | * rhashtable_init - initialize a new hash table |
| 954 | * @ht: hash table to be initialized |
| 955 | * @params: configuration parameters |
| 956 | * |
| 957 | * Initializes a new hash table based on the provided configuration |
| 958 | * parameters. A table can be configured either with a variable or |
| 959 | * fixed length key: |
| 960 | * |
| 961 | * Configuration Example 1: Fixed length keys |
| 962 | * struct test_obj { |
| 963 | * int key; |
| 964 | * void * my_member; |
| 965 | * struct rhash_head node; |
| 966 | * }; |
| 967 | * |
| 968 | * struct rhashtable_params params = { |
| 969 | * .head_offset = offsetof(struct test_obj, node), |
| 970 | * .key_offset = offsetof(struct test_obj, key), |
| 971 | * .key_len = sizeof(int), |
Daniel Borkmann | 8754589 | 2014-12-10 16:33:11 +0100 | [diff] [blame] | 972 | * .hashfn = jhash, |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 973 | * }; |
| 974 | * |
| 975 | * Configuration Example 2: Variable length keys |
| 976 | * struct test_obj { |
| 977 | * [...] |
| 978 | * struct rhash_head node; |
| 979 | * }; |
| 980 | * |
Patrick McHardy | 49f7b33 | 2015-03-25 13:07:45 +0000 | [diff] [blame] | 981 | * u32 my_hash_fn(const void *data, u32 len, u32 seed) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 982 | * { |
| 983 | * struct test_obj *obj = data; |
| 984 | * |
| 985 | * return [... hash ...]; |
| 986 | * } |
| 987 | * |
| 988 | * struct rhashtable_params params = { |
| 989 | * .head_offset = offsetof(struct test_obj, node), |
Daniel Borkmann | 8754589 | 2014-12-10 16:33:11 +0100 | [diff] [blame] | 990 | * .hashfn = jhash, |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 991 | * .obj_hashfn = my_hash_fn, |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 992 | * }; |
| 993 | */ |
Herbert Xu | 488fb86e | 2015-03-20 21:56:59 +1100 | [diff] [blame] | 994 | int rhashtable_init(struct rhashtable *ht, |
| 995 | const struct rhashtable_params *params) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 996 | { |
| 997 | struct bucket_table *tbl; |
| 998 | size_t size; |
| 999 | |
Herbert Xu | 31ccde2 | 2015-03-24 00:50:21 +1100 | [diff] [blame] | 1000 | if ((!params->key_len && !params->obj_hashfn) || |
Herbert Xu | 02fd97c | 2015-03-20 21:57:00 +1100 | [diff] [blame] | 1001 | (params->obj_hashfn && !params->obj_cmpfn)) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1002 | return -EINVAL; |
| 1003 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1004 | memset(ht, 0, sizeof(*ht)); |
| 1005 | mutex_init(&ht->mutex); |
Herbert Xu | ba7c95e | 2015-03-24 09:53:17 +1100 | [diff] [blame] | 1006 | spin_lock_init(&ht->lock); |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1007 | memcpy(&ht->p, params, sizeof(*params)); |
| 1008 | |
Thomas Graf | a998f71 | 2015-03-19 22:31:13 +0000 | [diff] [blame] | 1009 | if (params->min_size) |
| 1010 | ht->p.min_size = roundup_pow_of_two(params->min_size); |
| 1011 | |
Herbert Xu | 6d684e5 | 2017-04-27 13:44:51 +0800 | [diff] [blame] | 1012 | /* Cap total entries at 2^31 to avoid nelems overflow. */ |
| 1013 | ht->max_elems = 1u << 31; |
Herbert Xu | 2d2ab65 | 2017-04-28 14:10:48 +0800 | [diff] [blame] | 1014 | |
| 1015 | if (params->max_size) { |
| 1016 | ht->p.max_size = rounddown_pow_of_two(params->max_size); |
| 1017 | if (ht->p.max_size < ht->max_elems / 2) |
| 1018 | ht->max_elems = ht->p.max_size * 2; |
| 1019 | } |
Herbert Xu | 6d684e5 | 2017-04-27 13:44:51 +0800 | [diff] [blame] | 1020 | |
Florian Westphal | 48e75b43 | 2017-05-01 22:18:01 +0200 | [diff] [blame] | 1021 | ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); |
Thomas Graf | a998f71 | 2015-03-19 22:31:13 +0000 | [diff] [blame] | 1022 | |
Davidlohr Bueso | 107d01f | 2018-07-16 13:26:13 -0700 | [diff] [blame] | 1023 | size = rounded_hashtable_size(&ht->p); |
Herbert Xu | 3a32460 | 2015-12-16 18:13:14 +0800 | [diff] [blame] | 1024 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1025 | if (params->locks_mul) |
| 1026 | ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); |
| 1027 | else |
| 1028 | ht->p.locks_mul = BUCKET_LOCKS_PER_CPU; |
| 1029 | |
Herbert Xu | 31ccde2 | 2015-03-24 00:50:21 +1100 | [diff] [blame] | 1030 | ht->key_len = ht->p.key_len; |
| 1031 | if (!params->hashfn) { |
| 1032 | ht->p.hashfn = jhash; |
| 1033 | |
| 1034 | if (!(ht->key_len & (sizeof(u32) - 1))) { |
| 1035 | ht->key_len /= sizeof(u32); |
| 1036 | ht->p.hashfn = rhashtable_jhash2; |
| 1037 | } |
| 1038 | } |
| 1039 | |
Davidlohr Bueso | 2d22ecf | 2018-08-21 22:01:48 -0700 | [diff] [blame] | 1040 | /* |
| 1041 | * This is api initialization and thus we need to guarantee the |
| 1042 | * initial rhashtable allocation. Upon failure, retry with the |
| 1043 | * smallest possible size with __GFP_NOFAIL semantics. |
| 1044 | */ |
Herbert Xu | b9ecfda | 2015-03-24 00:50:27 +1100 | [diff] [blame] | 1045 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL); |
Davidlohr Bueso | 2d22ecf | 2018-08-21 22:01:48 -0700 | [diff] [blame] | 1046 | if (unlikely(tbl == NULL)) { |
| 1047 | size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); |
| 1048 | tbl = bucket_table_alloc(ht, size, GFP_KERNEL | __GFP_NOFAIL); |
| 1049 | } |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1050 | |
Ying Xue | 545a148 | 2015-01-07 13:41:57 +0800 | [diff] [blame] | 1051 | atomic_set(&ht->nelems, 0); |
Daniel Borkmann | a5b6846 | 2015-03-12 15:28:40 +0100 | [diff] [blame] | 1052 | |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1053 | RCU_INIT_POINTER(ht->tbl, tbl); |
| 1054 | |
Daniel Borkmann | 4c4b52d | 2015-02-25 16:31:54 +0100 | [diff] [blame] | 1055 | INIT_WORK(&ht->run_work, rht_deferred_worker); |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1056 | |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1057 | return 0; |
| 1058 | } |
| 1059 | EXPORT_SYMBOL_GPL(rhashtable_init); |
| 1060 | |
| 1061 | /** |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 1062 | * rhltable_init - initialize a new hash list table |
| 1063 | * @hlt: hash list table to be initialized |
| 1064 | * @params: configuration parameters |
| 1065 | * |
| 1066 | * Initializes a new hash list table. |
| 1067 | * |
| 1068 | * See documentation for rhashtable_init. |
| 1069 | */ |
| 1070 | int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) |
| 1071 | { |
| 1072 | int err; |
| 1073 | |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 1074 | err = rhashtable_init(&hlt->ht, params); |
| 1075 | hlt->ht.rhlist = true; |
| 1076 | return err; |
| 1077 | } |
| 1078 | EXPORT_SYMBOL_GPL(rhltable_init); |
| 1079 | |
| 1080 | static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, |
| 1081 | void (*free_fn)(void *ptr, void *arg), |
| 1082 | void *arg) |
| 1083 | { |
| 1084 | struct rhlist_head *list; |
| 1085 | |
| 1086 | if (!ht->rhlist) { |
| 1087 | free_fn(rht_obj(ht, obj), arg); |
| 1088 | return; |
| 1089 | } |
| 1090 | |
| 1091 | list = container_of(obj, struct rhlist_head, rhead); |
| 1092 | do { |
| 1093 | obj = &list->rhead; |
| 1094 | list = rht_dereference(list->next, ht); |
| 1095 | free_fn(rht_obj(ht, obj), arg); |
| 1096 | } while (list); |
| 1097 | } |
| 1098 | |
| 1099 | /** |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1100 | * rhashtable_free_and_destroy - free elements and destroy hash table |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1101 | * @ht: the hash table to destroy |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1102 | * @free_fn: callback to release resources of element |
| 1103 | * @arg: pointer passed to free_fn |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1104 | * |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1105 | * Stops an eventual async resize. If defined, invokes free_fn for each |
| 1106 | * element to releasal resources. Please note that RCU protected |
| 1107 | * readers may still be accessing the elements. Releasing of resources |
| 1108 | * must occur in a compatible manner. Then frees the bucket array. |
| 1109 | * |
| 1110 | * This function will eventually sleep to wait for an async resize |
| 1111 | * to complete. The caller is responsible that no further write operations |
| 1112 | * occurs in parallel. |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1113 | */ |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1114 | void rhashtable_free_and_destroy(struct rhashtable *ht, |
| 1115 | void (*free_fn)(void *ptr, void *arg), |
| 1116 | void *arg) |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1117 | { |
Taehee Yoo | 0026129 | 2018-07-08 11:55:51 +0900 | [diff] [blame] | 1118 | struct bucket_table *tbl, *next_tbl; |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1119 | unsigned int i; |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1120 | |
Daniel Borkmann | 4c4b52d | 2015-02-25 16:31:54 +0100 | [diff] [blame] | 1121 | cancel_work_sync(&ht->run_work); |
Ying Xue | 57699a4 | 2015-01-16 11:13:09 +0800 | [diff] [blame] | 1122 | |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1123 | mutex_lock(&ht->mutex); |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1124 | tbl = rht_dereference(ht->tbl, ht); |
Taehee Yoo | 0026129 | 2018-07-08 11:55:51 +0900 | [diff] [blame] | 1125 | restart: |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1126 | if (free_fn) { |
| 1127 | for (i = 0; i < tbl->size; i++) { |
| 1128 | struct rhash_head *pos, *next; |
| 1129 | |
Eric Dumazet | ae6da1f | 2018-03-31 12:58:48 -0700 | [diff] [blame] | 1130 | cond_resched(); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1131 | for (pos = rht_dereference(*rht_bucket(tbl, i), ht), |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1132 | next = !rht_is_a_nulls(pos) ? |
| 1133 | rht_dereference(pos->next, ht) : NULL; |
| 1134 | !rht_is_a_nulls(pos); |
| 1135 | pos = next, |
| 1136 | next = !rht_is_a_nulls(pos) ? |
| 1137 | rht_dereference(pos->next, ht) : NULL) |
Herbert Xu | ca26893 | 2016-09-19 19:00:09 +0800 | [diff] [blame] | 1138 | rhashtable_free_one(ht, pos, free_fn, arg); |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1139 | } |
| 1140 | } |
| 1141 | |
Taehee Yoo | 0026129 | 2018-07-08 11:55:51 +0900 | [diff] [blame] | 1142 | next_tbl = rht_dereference(tbl->future_tbl, ht); |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1143 | bucket_table_free(tbl); |
Taehee Yoo | 0026129 | 2018-07-08 11:55:51 +0900 | [diff] [blame] | 1144 | if (next_tbl) { |
| 1145 | tbl = next_tbl; |
| 1146 | goto restart; |
| 1147 | } |
Thomas Graf | 97defe1 | 2015-01-02 23:00:20 +0100 | [diff] [blame] | 1148 | mutex_unlock(&ht->mutex); |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1149 | } |
Thomas Graf | 6b6f302 | 2015-03-24 14:18:20 +0100 | [diff] [blame] | 1150 | EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); |
| 1151 | |
| 1152 | void rhashtable_destroy(struct rhashtable *ht) |
| 1153 | { |
| 1154 | return rhashtable_free_and_destroy(ht, NULL, NULL); |
| 1155 | } |
Thomas Graf | 7e1e776 | 2014-08-02 11:47:44 +0200 | [diff] [blame] | 1156 | EXPORT_SYMBOL_GPL(rhashtable_destroy); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1157 | |
| 1158 | struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl, |
| 1159 | unsigned int hash) |
| 1160 | { |
| 1161 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); |
NeilBrown | 82208d0d | 2018-11-30 10:26:50 +1100 | [diff] [blame] | 1162 | static struct rhash_head __rcu *rhnull; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1163 | unsigned int index = hash & ((1 << tbl->nest) - 1); |
| 1164 | unsigned int size = tbl->size >> tbl->nest; |
| 1165 | unsigned int subhash = hash; |
| 1166 | union nested_table *ntbl; |
| 1167 | |
| 1168 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); |
Herbert Xu | c4d2603 | 2017-02-25 22:39:50 +0800 | [diff] [blame] | 1169 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1170 | subhash >>= tbl->nest; |
| 1171 | |
| 1172 | while (ntbl && size > (1 << shift)) { |
| 1173 | index = subhash & ((1 << shift) - 1); |
Herbert Xu | c4d2603 | 2017-02-25 22:39:50 +0800 | [diff] [blame] | 1174 | ntbl = rht_dereference_bucket_rcu(ntbl[index].table, |
| 1175 | tbl, hash); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1176 | size >>= shift; |
| 1177 | subhash >>= shift; |
| 1178 | } |
| 1179 | |
NeilBrown | 82208d0d | 2018-11-30 10:26:50 +1100 | [diff] [blame] | 1180 | if (!ntbl) { |
| 1181 | if (!rhnull) |
| 1182 | INIT_RHT_NULLS_HEAD(rhnull); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1183 | return &rhnull; |
NeilBrown | 82208d0d | 2018-11-30 10:26:50 +1100 | [diff] [blame] | 1184 | } |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1185 | |
| 1186 | return &ntbl[subhash].bucket; |
| 1187 | |
| 1188 | } |
| 1189 | EXPORT_SYMBOL_GPL(rht_bucket_nested); |
| 1190 | |
| 1191 | struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, |
| 1192 | struct bucket_table *tbl, |
| 1193 | unsigned int hash) |
| 1194 | { |
| 1195 | const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); |
| 1196 | unsigned int index = hash & ((1 << tbl->nest) - 1); |
| 1197 | unsigned int size = tbl->size >> tbl->nest; |
| 1198 | union nested_table *ntbl; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1199 | |
| 1200 | ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); |
| 1201 | hash >>= tbl->nest; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1202 | ntbl = nested_table_alloc(ht, &ntbl[index].table, |
NeilBrown | 5af68ef | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 1203 | size <= (1 << shift)); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1204 | |
| 1205 | while (ntbl && size > (1 << shift)) { |
| 1206 | index = hash & ((1 << shift) - 1); |
| 1207 | size >>= shift; |
| 1208 | hash >>= shift; |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1209 | ntbl = nested_table_alloc(ht, &ntbl[index].table, |
NeilBrown | 5af68ef | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 1210 | size <= (1 << shift)); |
Herbert Xu | da20420 | 2017-02-11 19:26:47 +0800 | [diff] [blame] | 1211 | } |
| 1212 | |
| 1213 | if (!ntbl) |
| 1214 | return NULL; |
| 1215 | |
| 1216 | return &ntbl[hash].bucket; |
| 1217 | |
| 1218 | } |
| 1219 | EXPORT_SYMBOL_GPL(rht_bucket_nested_insert); |