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