1 // SPDX-License-Identifier: GPL-2.0-only <<
2 #include <linux/spinlock.h> 1 #include <linux/spinlock.h>
3 #include <linux/slab.h> 2 #include <linux/slab.h>
4 #include <linux/list.h> 3 #include <linux/list.h>
5 #include <linux/list_bl.h> 4 #include <linux/list_bl.h>
6 #include <linux/module.h> 5 #include <linux/module.h>
7 #include <linux/sched.h> 6 #include <linux/sched.h>
8 #include <linux/workqueue.h> 7 #include <linux/workqueue.h>
9 #include <linux/mbcache.h> 8 #include <linux/mbcache.h>
10 9
11 /* 10 /*
12 * Mbcache is a simple key-value store. Keys n 11 * Mbcache is a simple key-value store. Keys need not be unique, however
13 * key-value pairs are expected to be unique ( 12 * key-value pairs are expected to be unique (we use this fact in
14 * mb_cache_entry_delete_or_get()). !! 13 * mb_cache_entry_delete()).
15 * 14 *
16 * Ext2 and ext4 use this cache for deduplicat 15 * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
17 * Ext4 also uses it for deduplication of xatt 16 * Ext4 also uses it for deduplication of xattr values stored in inodes.
18 * They use hash of data as a key and provide 17 * They use hash of data as a key and provide a value that may represent a
19 * block or inode number. That's why keys need 18 * block or inode number. That's why keys need not be unique (hash of different
20 * data may be the same). However user provide 19 * data may be the same). However user provided value always uniquely
21 * identifies a cache entry. 20 * identifies a cache entry.
22 * 21 *
23 * We provide functions for creation and remov 22 * We provide functions for creation and removal of entries, search by key,
24 * and a special "delete entry with given key- 23 * and a special "delete entry with given key-value pair" operation. Fixed
25 * size hash table is used for fast key lookup 24 * size hash table is used for fast key lookups.
26 */ 25 */
27 26
28 struct mb_cache { 27 struct mb_cache {
29 /* Hash table of entries */ 28 /* Hash table of entries */
30 struct hlist_bl_head *c_hash; 29 struct hlist_bl_head *c_hash;
31 /* log2 of hash table size */ 30 /* log2 of hash table size */
32 int c_bucket_bits; 31 int c_bucket_bits;
33 /* Maximum entries in cache to avoid d 32 /* Maximum entries in cache to avoid degrading hash too much */
34 unsigned long c_max_entries; 33 unsigned long c_max_entries;
35 /* Protects c_list, c_entry_count */ 34 /* Protects c_list, c_entry_count */
36 spinlock_t c_list_lock; 35 spinlock_t c_list_lock;
37 struct list_head c_list; 36 struct list_head c_list;
38 /* Number of entries in cache */ 37 /* Number of entries in cache */
39 unsigned long c_entry_count; 38 unsigned long c_entry_count;
40 struct shrinker *c_shrink; !! 39 struct shrinker c_shrink;
41 /* Work for shrinking when the cache h 40 /* Work for shrinking when the cache has too many entries */
42 struct work_struct c_shrink_work; 41 struct work_struct c_shrink_work;
43 }; 42 };
44 43
45 static struct kmem_cache *mb_entry_cache; 44 static struct kmem_cache *mb_entry_cache;
46 45
47 static unsigned long mb_cache_shrink(struct mb 46 static unsigned long mb_cache_shrink(struct mb_cache *cache,
48 unsigned 47 unsigned long nr_to_scan);
49 48
50 static inline struct hlist_bl_head *mb_cache_e 49 static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
51 50 u32 key)
52 { 51 {
53 return &cache->c_hash[hash_32(key, cac 52 return &cache->c_hash[hash_32(key, cache->c_bucket_bits)];
54 } 53 }
55 54
56 /* 55 /*
57 * Number of entries to reclaim synchronously 56 * Number of entries to reclaim synchronously when there are too many entries
58 * in cache 57 * in cache
59 */ 58 */
60 #define SYNC_SHRINK_BATCH 64 59 #define SYNC_SHRINK_BATCH 64
61 60
62 /* 61 /*
63 * mb_cache_entry_create - create entry in cac 62 * mb_cache_entry_create - create entry in cache
64 * @cache - cache where the entry should be cr 63 * @cache - cache where the entry should be created
65 * @mask - gfp mask with which the entry shoul 64 * @mask - gfp mask with which the entry should be allocated
66 * @key - key of the entry 65 * @key - key of the entry
67 * @value - value of the entry 66 * @value - value of the entry
68 * @reusable - is the entry reusable by others 67 * @reusable - is the entry reusable by others?
69 * 68 *
70 * Creates entry in @cache with key @key and v 69 * Creates entry in @cache with key @key and value @value. The function returns
71 * -EBUSY if entry with the same key and value 70 * -EBUSY if entry with the same key and value already exists in cache.
72 * Otherwise 0 is returned. 71 * Otherwise 0 is returned.
73 */ 72 */
74 int mb_cache_entry_create(struct mb_cache *cac 73 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
75 u64 value, bool reus 74 u64 value, bool reusable)
76 { 75 {
77 struct mb_cache_entry *entry, *dup; 76 struct mb_cache_entry *entry, *dup;
78 struct hlist_bl_node *dup_node; 77 struct hlist_bl_node *dup_node;
79 struct hlist_bl_head *head; 78 struct hlist_bl_head *head;
80 79
81 /* Schedule background reclaim if ther 80 /* Schedule background reclaim if there are too many entries */
82 if (cache->c_entry_count >= cache->c_m 81 if (cache->c_entry_count >= cache->c_max_entries)
83 schedule_work(&cache->c_shrink 82 schedule_work(&cache->c_shrink_work);
84 /* Do some sync reclaim if background 83 /* Do some sync reclaim if background reclaim cannot keep up */
85 if (cache->c_entry_count >= 2*cache->c 84 if (cache->c_entry_count >= 2*cache->c_max_entries)
86 mb_cache_shrink(cache, SYNC_SH 85 mb_cache_shrink(cache, SYNC_SHRINK_BATCH);
87 86
88 entry = kmem_cache_alloc(mb_entry_cach 87 entry = kmem_cache_alloc(mb_entry_cache, mask);
89 if (!entry) 88 if (!entry)
90 return -ENOMEM; 89 return -ENOMEM;
91 90
92 INIT_LIST_HEAD(&entry->e_list); 91 INIT_LIST_HEAD(&entry->e_list);
93 /* !! 92 /* One ref for hash, one ref returned */
94 * We create entry with two references !! 93 atomic_set(&entry->e_refcnt, 1);
95 * hash table, the other reference is <<
96 * mb_cache_entry_delete_or_get() unti <<
97 * avoids nesting of cache->c_list_loc <<
98 * is problematic for RT. <<
99 */ <<
100 atomic_set(&entry->e_refcnt, 2); <<
101 entry->e_key = key; 94 entry->e_key = key;
102 entry->e_value = value; 95 entry->e_value = value;
103 entry->e_flags = 0; !! 96 entry->e_reusable = reusable;
104 if (reusable) !! 97 entry->e_referenced = 0;
105 set_bit(MBE_REUSABLE_B, &entry <<
106 head = mb_cache_entry_head(cache, key) 98 head = mb_cache_entry_head(cache, key);
107 hlist_bl_lock(head); 99 hlist_bl_lock(head);
108 hlist_bl_for_each_entry(dup, dup_node, 100 hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) {
109 if (dup->e_key == key && dup-> 101 if (dup->e_key == key && dup->e_value == value) {
110 hlist_bl_unlock(head); 102 hlist_bl_unlock(head);
111 kmem_cache_free(mb_ent 103 kmem_cache_free(mb_entry_cache, entry);
112 return -EBUSY; 104 return -EBUSY;
113 } 105 }
114 } 106 }
115 hlist_bl_add_head(&entry->e_hash_list, 107 hlist_bl_add_head(&entry->e_hash_list, head);
116 hlist_bl_unlock(head); 108 hlist_bl_unlock(head);
>> 109
117 spin_lock(&cache->c_list_lock); 110 spin_lock(&cache->c_list_lock);
118 list_add_tail(&entry->e_list, &cache-> 111 list_add_tail(&entry->e_list, &cache->c_list);
>> 112 /* Grab ref for LRU list */
>> 113 atomic_inc(&entry->e_refcnt);
119 cache->c_entry_count++; 114 cache->c_entry_count++;
120 spin_unlock(&cache->c_list_lock); 115 spin_unlock(&cache->c_list_lock);
121 mb_cache_entry_put(cache, entry); <<
122 116
123 return 0; 117 return 0;
124 } 118 }
125 EXPORT_SYMBOL(mb_cache_entry_create); 119 EXPORT_SYMBOL(mb_cache_entry_create);
126 120
127 void __mb_cache_entry_free(struct mb_cache *ca !! 121 void __mb_cache_entry_free(struct mb_cache_entry *entry)
128 { 122 {
129 struct hlist_bl_head *head; <<
130 <<
131 head = mb_cache_entry_head(cache, entr <<
132 hlist_bl_lock(head); <<
133 hlist_bl_del(&entry->e_hash_list); <<
134 hlist_bl_unlock(head); <<
135 kmem_cache_free(mb_entry_cache, entry) 123 kmem_cache_free(mb_entry_cache, entry);
136 } 124 }
137 EXPORT_SYMBOL(__mb_cache_entry_free); 125 EXPORT_SYMBOL(__mb_cache_entry_free);
138 126
139 /* <<
140 * mb_cache_entry_wait_unused - wait to be the <<
141 * <<
142 * @entry - entry to work on <<
143 * <<
144 * Wait to be the last user of the entry. <<
145 */ <<
146 void mb_cache_entry_wait_unused(struct mb_cach <<
147 { <<
148 wait_var_event(&entry->e_refcnt, atomi <<
149 } <<
150 EXPORT_SYMBOL(mb_cache_entry_wait_unused); <<
151 <<
152 static struct mb_cache_entry *__entry_find(str 127 static struct mb_cache_entry *__entry_find(struct mb_cache *cache,
153 str 128 struct mb_cache_entry *entry,
154 u32 129 u32 key)
155 { 130 {
156 struct mb_cache_entry *old_entry = ent 131 struct mb_cache_entry *old_entry = entry;
157 struct hlist_bl_node *node; 132 struct hlist_bl_node *node;
158 struct hlist_bl_head *head; 133 struct hlist_bl_head *head;
159 134
160 head = mb_cache_entry_head(cache, key) 135 head = mb_cache_entry_head(cache, key);
161 hlist_bl_lock(head); 136 hlist_bl_lock(head);
162 if (entry && !hlist_bl_unhashed(&entry 137 if (entry && !hlist_bl_unhashed(&entry->e_hash_list))
163 node = entry->e_hash_list.next 138 node = entry->e_hash_list.next;
164 else 139 else
165 node = hlist_bl_first(head); 140 node = hlist_bl_first(head);
166 while (node) { 141 while (node) {
167 entry = hlist_bl_entry(node, s 142 entry = hlist_bl_entry(node, struct mb_cache_entry,
168 e_hash_ 143 e_hash_list);
169 if (entry->e_key == key && !! 144 if (entry->e_key == key && entry->e_reusable) {
170 test_bit(MBE_REUSABLE_B, & !! 145 atomic_inc(&entry->e_refcnt);
171 atomic_inc_not_zero(&entry <<
172 goto out; 146 goto out;
>> 147 }
173 node = node->next; 148 node = node->next;
174 } 149 }
175 entry = NULL; 150 entry = NULL;
176 out: 151 out:
177 hlist_bl_unlock(head); 152 hlist_bl_unlock(head);
178 if (old_entry) 153 if (old_entry)
179 mb_cache_entry_put(cache, old_ 154 mb_cache_entry_put(cache, old_entry);
180 155
181 return entry; 156 return entry;
182 } 157 }
183 158
184 /* 159 /*
185 * mb_cache_entry_find_first - find the first 160 * mb_cache_entry_find_first - find the first reusable entry with the given key
186 * @cache: cache where we should search 161 * @cache: cache where we should search
187 * @key: key to look for 162 * @key: key to look for
188 * 163 *
189 * Search in @cache for a reusable entry with 164 * Search in @cache for a reusable entry with key @key. Grabs reference to the
190 * first reusable entry found and returns the 165 * first reusable entry found and returns the entry.
191 */ 166 */
192 struct mb_cache_entry *mb_cache_entry_find_fir 167 struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
193 168 u32 key)
194 { 169 {
195 return __entry_find(cache, NULL, key); 170 return __entry_find(cache, NULL, key);
196 } 171 }
197 EXPORT_SYMBOL(mb_cache_entry_find_first); 172 EXPORT_SYMBOL(mb_cache_entry_find_first);
198 173
199 /* 174 /*
200 * mb_cache_entry_find_next - find next reusab 175 * mb_cache_entry_find_next - find next reusable entry with the same key
201 * @cache: cache where we should search 176 * @cache: cache where we should search
202 * @entry: entry to start search from 177 * @entry: entry to start search from
203 * 178 *
204 * Finds next reusable entry in the hash chain 179 * Finds next reusable entry in the hash chain which has the same key as @entry.
205 * If @entry is unhashed (which can happen whe 180 * If @entry is unhashed (which can happen when deletion of entry races with the
206 * search), finds the first reusable entry in 181 * search), finds the first reusable entry in the hash chain. The function drops
207 * reference to @entry and returns with a refe 182 * reference to @entry and returns with a reference to the found entry.
208 */ 183 */
209 struct mb_cache_entry *mb_cache_entry_find_nex 184 struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
210 185 struct mb_cache_entry *entry)
211 { 186 {
212 return __entry_find(cache, entry, entr 187 return __entry_find(cache, entry, entry->e_key);
213 } 188 }
214 EXPORT_SYMBOL(mb_cache_entry_find_next); 189 EXPORT_SYMBOL(mb_cache_entry_find_next);
215 190
216 /* 191 /*
217 * mb_cache_entry_get - get a cache entry by v 192 * mb_cache_entry_get - get a cache entry by value (and key)
218 * @cache - cache we work with 193 * @cache - cache we work with
219 * @key - key 194 * @key - key
220 * @value - value 195 * @value - value
221 */ 196 */
222 struct mb_cache_entry *mb_cache_entry_get(stru 197 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
223 u64 198 u64 value)
224 { 199 {
225 struct hlist_bl_node *node; 200 struct hlist_bl_node *node;
226 struct hlist_bl_head *head; 201 struct hlist_bl_head *head;
227 struct mb_cache_entry *entry; 202 struct mb_cache_entry *entry;
228 203
229 head = mb_cache_entry_head(cache, key) 204 head = mb_cache_entry_head(cache, key);
230 hlist_bl_lock(head); 205 hlist_bl_lock(head);
231 hlist_bl_for_each_entry(entry, node, h 206 hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
232 if (entry->e_key == key && ent !! 207 if (entry->e_key == key && entry->e_value == value) {
233 atomic_inc_not_zero(&entry !! 208 atomic_inc(&entry->e_refcnt);
234 goto out; 209 goto out;
>> 210 }
235 } 211 }
236 entry = NULL; 212 entry = NULL;
237 out: 213 out:
238 hlist_bl_unlock(head); 214 hlist_bl_unlock(head);
239 return entry; 215 return entry;
240 } 216 }
241 EXPORT_SYMBOL(mb_cache_entry_get); 217 EXPORT_SYMBOL(mb_cache_entry_get);
242 218
243 /* mb_cache_entry_delete_or_get - remove a cac !! 219 /* mb_cache_entry_delete - remove a cache entry
244 * @cache - cache we work with 220 * @cache - cache we work with
245 * @key - key 221 * @key - key
246 * @value - value 222 * @value - value
247 * 223 *
248 * Remove entry from cache @cache with key @ke !! 224 * Remove entry from cache @cache with key @key and value @value.
249 * happens only if the entry is unused. The fu <<
250 * entry was successfully removed or there's n <<
251 * function grabs reference of the entry that <<
252 * still has users and return it. <<
253 */ 225 */
254 struct mb_cache_entry *mb_cache_entry_delete_o !! 226 void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value)
255 <<
256 { 227 {
>> 228 struct hlist_bl_node *node;
>> 229 struct hlist_bl_head *head;
257 struct mb_cache_entry *entry; 230 struct mb_cache_entry *entry;
258 231
259 entry = mb_cache_entry_get(cache, key, !! 232 head = mb_cache_entry_head(cache, key);
260 if (!entry) !! 233 hlist_bl_lock(head);
261 return NULL; !! 234 hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
262 !! 235 if (entry->e_key == key && entry->e_value == value) {
263 /* !! 236 /* We keep hash list reference to keep entry alive */
264 * Drop the ref we got from mb_cache_e !! 237 hlist_bl_del_init(&entry->e_hash_list);
265 * ref if we are the last user !! 238 hlist_bl_unlock(head);
266 */ !! 239 spin_lock(&cache->c_list_lock);
267 if (atomic_cmpxchg(&entry->e_refcnt, 2 !! 240 if (!list_empty(&entry->e_list)) {
268 return entry; !! 241 list_del_init(&entry->e_list);
269 !! 242 if (!WARN_ONCE(cache->c_entry_count == 0,
270 spin_lock(&cache->c_list_lock); !! 243 "mbcache: attempt to decrement c_entry_count past zero"))
271 if (!list_empty(&entry->e_list)) !! 244 cache->c_entry_count--;
272 list_del_init(&entry->e_list); !! 245 atomic_dec(&entry->e_refcnt);
273 cache->c_entry_count--; !! 246 }
274 spin_unlock(&cache->c_list_lock); !! 247 spin_unlock(&cache->c_list_lock);
275 __mb_cache_entry_free(cache, entry); !! 248 mb_cache_entry_put(cache, entry);
276 return NULL; !! 249 return;
>> 250 }
>> 251 }
>> 252 hlist_bl_unlock(head);
277 } 253 }
278 EXPORT_SYMBOL(mb_cache_entry_delete_or_get); !! 254 EXPORT_SYMBOL(mb_cache_entry_delete);
279 255
280 /* mb_cache_entry_touch - cache entry got used 256 /* mb_cache_entry_touch - cache entry got used
281 * @cache - cache the entry belongs to 257 * @cache - cache the entry belongs to
282 * @entry - entry that got used 258 * @entry - entry that got used
283 * 259 *
284 * Marks entry as used to give hit higher chan 260 * Marks entry as used to give hit higher chances of surviving in cache.
285 */ 261 */
286 void mb_cache_entry_touch(struct mb_cache *cac 262 void mb_cache_entry_touch(struct mb_cache *cache,
287 struct mb_cache_entr 263 struct mb_cache_entry *entry)
288 { 264 {
289 set_bit(MBE_REFERENCED_B, &entry->e_fl !! 265 entry->e_referenced = 1;
290 } 266 }
291 EXPORT_SYMBOL(mb_cache_entry_touch); 267 EXPORT_SYMBOL(mb_cache_entry_touch);
292 268
293 static unsigned long mb_cache_count(struct shr 269 static unsigned long mb_cache_count(struct shrinker *shrink,
294 struct shr 270 struct shrink_control *sc)
295 { 271 {
296 struct mb_cache *cache = shrink->priva !! 272 struct mb_cache *cache = container_of(shrink, struct mb_cache,
>> 273 c_shrink);
297 274
298 return cache->c_entry_count; 275 return cache->c_entry_count;
299 } 276 }
300 277
301 /* Shrink number of entries in cache */ 278 /* Shrink number of entries in cache */
302 static unsigned long mb_cache_shrink(struct mb 279 static unsigned long mb_cache_shrink(struct mb_cache *cache,
303 unsigned 280 unsigned long nr_to_scan)
304 { 281 {
305 struct mb_cache_entry *entry; 282 struct mb_cache_entry *entry;
>> 283 struct hlist_bl_head *head;
306 unsigned long shrunk = 0; 284 unsigned long shrunk = 0;
307 285
308 spin_lock(&cache->c_list_lock); 286 spin_lock(&cache->c_list_lock);
309 while (nr_to_scan-- && !list_empty(&ca 287 while (nr_to_scan-- && !list_empty(&cache->c_list)) {
310 entry = list_first_entry(&cach 288 entry = list_first_entry(&cache->c_list,
311 struc 289 struct mb_cache_entry, e_list);
312 /* Drop initial hash reference !! 290 if (entry->e_referenced) {
313 if (test_bit(MBE_REFERENCED_B, !! 291 entry->e_referenced = 0;
314 atomic_cmpxchg(&entry->e_r <<
315 clear_bit(MBE_REFERENC <<
316 list_move_tail(&entry- 292 list_move_tail(&entry->e_list, &cache->c_list);
317 continue; 293 continue;
318 } 294 }
319 list_del_init(&entry->e_list); 295 list_del_init(&entry->e_list);
320 cache->c_entry_count--; 296 cache->c_entry_count--;
>> 297 /*
>> 298 * We keep LRU list reference so that entry doesn't go away
>> 299 * from under us.
>> 300 */
321 spin_unlock(&cache->c_list_loc 301 spin_unlock(&cache->c_list_lock);
322 __mb_cache_entry_free(cache, e !! 302 head = mb_cache_entry_head(cache, entry->e_key);
323 shrunk++; !! 303 hlist_bl_lock(head);
>> 304 if (!hlist_bl_unhashed(&entry->e_hash_list)) {
>> 305 hlist_bl_del_init(&entry->e_hash_list);
>> 306 atomic_dec(&entry->e_refcnt);
>> 307 }
>> 308 hlist_bl_unlock(head);
>> 309 if (mb_cache_entry_put(cache, entry))
>> 310 shrunk++;
324 cond_resched(); 311 cond_resched();
325 spin_lock(&cache->c_list_lock) 312 spin_lock(&cache->c_list_lock);
326 } 313 }
327 spin_unlock(&cache->c_list_lock); 314 spin_unlock(&cache->c_list_lock);
328 315
329 return shrunk; 316 return shrunk;
330 } 317 }
331 318
332 static unsigned long mb_cache_scan(struct shri 319 static unsigned long mb_cache_scan(struct shrinker *shrink,
333 struct shri 320 struct shrink_control *sc)
334 { 321 {
335 struct mb_cache *cache = shrink->priva !! 322 struct mb_cache *cache = container_of(shrink, struct mb_cache,
>> 323 c_shrink);
336 return mb_cache_shrink(cache, sc->nr_t 324 return mb_cache_shrink(cache, sc->nr_to_scan);
337 } 325 }
338 326
339 /* We shrink 1/X of the cache when we have too 327 /* We shrink 1/X of the cache when we have too many entries in it */
340 #define SHRINK_DIVISOR 16 328 #define SHRINK_DIVISOR 16
341 329
342 static void mb_cache_shrink_worker(struct work 330 static void mb_cache_shrink_worker(struct work_struct *work)
343 { 331 {
344 struct mb_cache *cache = container_of( 332 struct mb_cache *cache = container_of(work, struct mb_cache,
345 333 c_shrink_work);
346 mb_cache_shrink(cache, cache->c_max_en 334 mb_cache_shrink(cache, cache->c_max_entries / SHRINK_DIVISOR);
347 } 335 }
348 336
349 /* 337 /*
350 * mb_cache_create - create cache 338 * mb_cache_create - create cache
351 * @bucket_bits: log2 of the hash table size 339 * @bucket_bits: log2 of the hash table size
352 * 340 *
353 * Create cache for keys with 2^bucket_bits ha 341 * Create cache for keys with 2^bucket_bits hash entries.
354 */ 342 */
355 struct mb_cache *mb_cache_create(int bucket_bi 343 struct mb_cache *mb_cache_create(int bucket_bits)
356 { 344 {
357 struct mb_cache *cache; 345 struct mb_cache *cache;
358 unsigned long bucket_count = 1UL << bu 346 unsigned long bucket_count = 1UL << bucket_bits;
359 unsigned long i; 347 unsigned long i;
360 348
361 cache = kzalloc(sizeof(struct mb_cache 349 cache = kzalloc(sizeof(struct mb_cache), GFP_KERNEL);
362 if (!cache) 350 if (!cache)
363 goto err_out; 351 goto err_out;
364 cache->c_bucket_bits = bucket_bits; 352 cache->c_bucket_bits = bucket_bits;
365 cache->c_max_entries = bucket_count << 353 cache->c_max_entries = bucket_count << 4;
366 INIT_LIST_HEAD(&cache->c_list); 354 INIT_LIST_HEAD(&cache->c_list);
367 spin_lock_init(&cache->c_list_lock); 355 spin_lock_init(&cache->c_list_lock);
368 cache->c_hash = kmalloc_array(bucket_c 356 cache->c_hash = kmalloc_array(bucket_count,
369 sizeof(s 357 sizeof(struct hlist_bl_head),
370 GFP_KERN 358 GFP_KERNEL);
371 if (!cache->c_hash) { 359 if (!cache->c_hash) {
372 kfree(cache); 360 kfree(cache);
373 goto err_out; 361 goto err_out;
374 } 362 }
375 for (i = 0; i < bucket_count; i++) 363 for (i = 0; i < bucket_count; i++)
376 INIT_HLIST_BL_HEAD(&cache->c_h 364 INIT_HLIST_BL_HEAD(&cache->c_hash[i]);
377 365
378 cache->c_shrink = shrinker_alloc(0, "m !! 366 cache->c_shrink.count_objects = mb_cache_count;
379 if (!cache->c_shrink) { !! 367 cache->c_shrink.scan_objects = mb_cache_scan;
>> 368 cache->c_shrink.seeks = DEFAULT_SEEKS;
>> 369 if (register_shrinker(&cache->c_shrink)) {
380 kfree(cache->c_hash); 370 kfree(cache->c_hash);
381 kfree(cache); 371 kfree(cache);
382 goto err_out; 372 goto err_out;
383 } 373 }
384 374
385 cache->c_shrink->count_objects = mb_ca <<
386 cache->c_shrink->scan_objects = mb_cac <<
387 cache->c_shrink->private_data = cache; <<
388 <<
389 shrinker_register(cache->c_shrink); <<
390 <<
391 INIT_WORK(&cache->c_shrink_work, mb_ca 375 INIT_WORK(&cache->c_shrink_work, mb_cache_shrink_worker);
392 376
393 return cache; 377 return cache;
394 378
395 err_out: 379 err_out:
396 return NULL; 380 return NULL;
397 } 381 }
398 EXPORT_SYMBOL(mb_cache_create); 382 EXPORT_SYMBOL(mb_cache_create);
399 383
400 /* 384 /*
401 * mb_cache_destroy - destroy cache 385 * mb_cache_destroy - destroy cache
402 * @cache: the cache to destroy 386 * @cache: the cache to destroy
403 * 387 *
404 * Free all entries in cache and cache itself. 388 * Free all entries in cache and cache itself. Caller must make sure nobody
405 * (except shrinker) can reach @cache when cal 389 * (except shrinker) can reach @cache when calling this.
406 */ 390 */
407 void mb_cache_destroy(struct mb_cache *cache) 391 void mb_cache_destroy(struct mb_cache *cache)
408 { 392 {
409 struct mb_cache_entry *entry, *next; 393 struct mb_cache_entry *entry, *next;
410 394
411 shrinker_free(cache->c_shrink); !! 395 unregister_shrinker(&cache->c_shrink);
412 396
413 /* 397 /*
414 * We don't bother with any locking. C 398 * We don't bother with any locking. Cache must not be used at this
415 * point. 399 * point.
416 */ 400 */
417 list_for_each_entry_safe(entry, next, 401 list_for_each_entry_safe(entry, next, &cache->c_list, e_list) {
>> 402 if (!hlist_bl_unhashed(&entry->e_hash_list)) {
>> 403 hlist_bl_del_init(&entry->e_hash_list);
>> 404 atomic_dec(&entry->e_refcnt);
>> 405 } else
>> 406 WARN_ON(1);
418 list_del(&entry->e_list); 407 list_del(&entry->e_list);
419 WARN_ON(atomic_read(&entry->e_ 408 WARN_ON(atomic_read(&entry->e_refcnt) != 1);
420 mb_cache_entry_put(cache, entr 409 mb_cache_entry_put(cache, entry);
421 } 410 }
422 kfree(cache->c_hash); 411 kfree(cache->c_hash);
423 kfree(cache); 412 kfree(cache);
424 } 413 }
425 EXPORT_SYMBOL(mb_cache_destroy); 414 EXPORT_SYMBOL(mb_cache_destroy);
426 415
427 static int __init mbcache_init(void) 416 static int __init mbcache_init(void)
428 { 417 {
429 mb_entry_cache = KMEM_CACHE(mb_cache_e !! 418 mb_entry_cache = kmem_cache_create("mbcache",
>> 419 sizeof(struct mb_cache_entry), 0,
>> 420 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL);
430 if (!mb_entry_cache) 421 if (!mb_entry_cache)
431 return -ENOMEM; 422 return -ENOMEM;
432 return 0; 423 return 0;
433 } 424 }
434 425
435 static void __exit mbcache_exit(void) 426 static void __exit mbcache_exit(void)
436 { 427 {
437 kmem_cache_destroy(mb_entry_cache); 428 kmem_cache_destroy(mb_entry_cache);
438 } 429 }
439 430
440 module_init(mbcache_init) 431 module_init(mbcache_init)
441 module_exit(mbcache_exit) 432 module_exit(mbcache_exit)
442 433
443 MODULE_AUTHOR("Jan Kara <jack@suse.cz>"); 434 MODULE_AUTHOR("Jan Kara <jack@suse.cz>");
444 MODULE_DESCRIPTION("Meta block cache (for exte 435 MODULE_DESCRIPTION("Meta block cache (for extended attributes)");
445 MODULE_LICENSE("GPL"); 436 MODULE_LICENSE("GPL");
446 437
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