1
2
3
4
5
6
7#include "dm.h"
8#include "dm-bio-prison-v2.h"
9
10#include <linux/spinlock.h>
11#include <linux/mempool.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/rwsem.h>
15
16
17
18#define MIN_CELLS 1024
19
20struct dm_bio_prison_v2 {
21 struct workqueue_struct *wq;
22
23 spinlock_t lock;
24 struct rb_root cells;
25 mempool_t cell_pool;
26};
27
28static struct kmem_cache *_cell_cache;
29
30
31
32
33
34
35
36struct dm_bio_prison_v2 *dm_bio_prison_create_v2(struct workqueue_struct *wq)
37{
38 struct dm_bio_prison_v2 *prison = kzalloc(sizeof(*prison), GFP_KERNEL);
39 int ret;
40
41 if (!prison)
42 return NULL;
43
44 prison->wq = wq;
45 spin_lock_init(&prison->lock);
46
47 ret = mempool_init_slab_pool(&prison->cell_pool, MIN_CELLS, _cell_cache);
48 if (ret) {
49 kfree(prison);
50 return NULL;
51 }
52
53 prison->cells = RB_ROOT;
54
55 return prison;
56}
57EXPORT_SYMBOL_GPL(dm_bio_prison_create_v2);
58
59void dm_bio_prison_destroy_v2(struct dm_bio_prison_v2 *prison)
60{
61 mempool_exit(&prison->cell_pool);
62 kfree(prison);
63}
64EXPORT_SYMBOL_GPL(dm_bio_prison_destroy_v2);
65
66struct dm_bio_prison_cell_v2 *dm_bio_prison_alloc_cell_v2(struct dm_bio_prison_v2 *prison, gfp_t gfp)
67{
68 return mempool_alloc(&prison->cell_pool, gfp);
69}
70EXPORT_SYMBOL_GPL(dm_bio_prison_alloc_cell_v2);
71
72void dm_bio_prison_free_cell_v2(struct dm_bio_prison_v2 *prison,
73 struct dm_bio_prison_cell_v2 *cell)
74{
75 mempool_free(cell, &prison->cell_pool);
76}
77EXPORT_SYMBOL_GPL(dm_bio_prison_free_cell_v2);
78
79static void __setup_new_cell(struct dm_cell_key_v2 *key,
80 struct dm_bio_prison_cell_v2 *cell)
81{
82 memset(cell, 0, sizeof(*cell));
83 memcpy(&cell->key, key, sizeof(cell->key));
84 bio_list_init(&cell->bios);
85}
86
87static int cmp_keys(struct dm_cell_key_v2 *lhs,
88 struct dm_cell_key_v2 *rhs)
89{
90 if (lhs->virtual < rhs->virtual)
91 return -1;
92
93 if (lhs->virtual > rhs->virtual)
94 return 1;
95
96 if (lhs->dev < rhs->dev)
97 return -1;
98
99 if (lhs->dev > rhs->dev)
100 return 1;
101
102 if (lhs->block_end <= rhs->block_begin)
103 return -1;
104
105 if (lhs->block_begin >= rhs->block_end)
106 return 1;
107
108 return 0;
109}
110
111
112
113
114static bool __find_or_insert(struct dm_bio_prison_v2 *prison,
115 struct dm_cell_key_v2 *key,
116 struct dm_bio_prison_cell_v2 *cell_prealloc,
117 struct dm_bio_prison_cell_v2 **result)
118{
119 int r;
120 struct rb_node **new = &prison->cells.rb_node, *parent = NULL;
121
122 while (*new) {
123 struct dm_bio_prison_cell_v2 *cell =
124 rb_entry(*new, struct dm_bio_prison_cell_v2, node);
125
126 r = cmp_keys(key, &cell->key);
127
128 parent = *new;
129 if (r < 0)
130 new = &((*new)->rb_left);
131
132 else if (r > 0)
133 new = &((*new)->rb_right);
134
135 else {
136 *result = cell;
137 return true;
138 }
139 }
140
141 __setup_new_cell(key, cell_prealloc);
142 *result = cell_prealloc;
143 rb_link_node(&cell_prealloc->node, parent, new);
144 rb_insert_color(&cell_prealloc->node, &prison->cells);
145
146 return false;
147}
148
149static bool __get(struct dm_bio_prison_v2 *prison,
150 struct dm_cell_key_v2 *key,
151 unsigned lock_level,
152 struct bio *inmate,
153 struct dm_bio_prison_cell_v2 *cell_prealloc,
154 struct dm_bio_prison_cell_v2 **cell)
155{
156 if (__find_or_insert(prison, key, cell_prealloc, cell)) {
157 if ((*cell)->exclusive_lock) {
158 if (lock_level <= (*cell)->exclusive_level) {
159 bio_list_add(&(*cell)->bios, inmate);
160 return false;
161 }
162 }
163
164 (*cell)->shared_count++;
165
166 } else
167 (*cell)->shared_count = 1;
168
169 return true;
170}
171
172bool dm_cell_get_v2(struct dm_bio_prison_v2 *prison,
173 struct dm_cell_key_v2 *key,
174 unsigned lock_level,
175 struct bio *inmate,
176 struct dm_bio_prison_cell_v2 *cell_prealloc,
177 struct dm_bio_prison_cell_v2 **cell_result)
178{
179 int r;
180
181 spin_lock_irq(&prison->lock);
182 r = __get(prison, key, lock_level, inmate, cell_prealloc, cell_result);
183 spin_unlock_irq(&prison->lock);
184
185 return r;
186}
187EXPORT_SYMBOL_GPL(dm_cell_get_v2);
188
189static bool __put(struct dm_bio_prison_v2 *prison,
190 struct dm_bio_prison_cell_v2 *cell)
191{
192 BUG_ON(!cell->shared_count);
193 cell->shared_count--;
194
195
196 if (!cell->shared_count) {
197 if (cell->exclusive_lock){
198 if (cell->quiesce_continuation) {
199 queue_work(prison->wq, cell->quiesce_continuation);
200 cell->quiesce_continuation = NULL;
201 }
202 } else {
203 rb_erase(&cell->node, &prison->cells);
204 return true;
205 }
206 }
207
208 return false;
209}
210
211bool dm_cell_put_v2(struct dm_bio_prison_v2 *prison,
212 struct dm_bio_prison_cell_v2 *cell)
213{
214 bool r;
215 unsigned long flags;
216
217 spin_lock_irqsave(&prison->lock, flags);
218 r = __put(prison, cell);
219 spin_unlock_irqrestore(&prison->lock, flags);
220
221 return r;
222}
223EXPORT_SYMBOL_GPL(dm_cell_put_v2);
224
225static int __lock(struct dm_bio_prison_v2 *prison,
226 struct dm_cell_key_v2 *key,
227 unsigned lock_level,
228 struct dm_bio_prison_cell_v2 *cell_prealloc,
229 struct dm_bio_prison_cell_v2 **cell_result)
230{
231 struct dm_bio_prison_cell_v2 *cell;
232
233 if (__find_or_insert(prison, key, cell_prealloc, &cell)) {
234 if (cell->exclusive_lock)
235 return -EBUSY;
236
237 cell->exclusive_lock = true;
238 cell->exclusive_level = lock_level;
239 *cell_result = cell;
240
241
242
243 return cell->shared_count > 0;
244
245 } else {
246 cell = cell_prealloc;
247 cell->shared_count = 0;
248 cell->exclusive_lock = true;
249 cell->exclusive_level = lock_level;
250 *cell_result = cell;
251 }
252
253 return 0;
254}
255
256int dm_cell_lock_v2(struct dm_bio_prison_v2 *prison,
257 struct dm_cell_key_v2 *key,
258 unsigned lock_level,
259 struct dm_bio_prison_cell_v2 *cell_prealloc,
260 struct dm_bio_prison_cell_v2 **cell_result)
261{
262 int r;
263
264 spin_lock_irq(&prison->lock);
265 r = __lock(prison, key, lock_level, cell_prealloc, cell_result);
266 spin_unlock_irq(&prison->lock);
267
268 return r;
269}
270EXPORT_SYMBOL_GPL(dm_cell_lock_v2);
271
272static void __quiesce(struct dm_bio_prison_v2 *prison,
273 struct dm_bio_prison_cell_v2 *cell,
274 struct work_struct *continuation)
275{
276 if (!cell->shared_count)
277 queue_work(prison->wq, continuation);
278 else
279 cell->quiesce_continuation = continuation;
280}
281
282void dm_cell_quiesce_v2(struct dm_bio_prison_v2 *prison,
283 struct dm_bio_prison_cell_v2 *cell,
284 struct work_struct *continuation)
285{
286 spin_lock_irq(&prison->lock);
287 __quiesce(prison, cell, continuation);
288 spin_unlock_irq(&prison->lock);
289}
290EXPORT_SYMBOL_GPL(dm_cell_quiesce_v2);
291
292static int __promote(struct dm_bio_prison_v2 *prison,
293 struct dm_bio_prison_cell_v2 *cell,
294 unsigned new_lock_level)
295{
296 if (!cell->exclusive_lock)
297 return -EINVAL;
298
299 cell->exclusive_level = new_lock_level;
300 return cell->shared_count > 0;
301}
302
303int dm_cell_lock_promote_v2(struct dm_bio_prison_v2 *prison,
304 struct dm_bio_prison_cell_v2 *cell,
305 unsigned new_lock_level)
306{
307 int r;
308
309 spin_lock_irq(&prison->lock);
310 r = __promote(prison, cell, new_lock_level);
311 spin_unlock_irq(&prison->lock);
312
313 return r;
314}
315EXPORT_SYMBOL_GPL(dm_cell_lock_promote_v2);
316
317static bool __unlock(struct dm_bio_prison_v2 *prison,
318 struct dm_bio_prison_cell_v2 *cell,
319 struct bio_list *bios)
320{
321 BUG_ON(!cell->exclusive_lock);
322
323 bio_list_merge(bios, &cell->bios);
324 bio_list_init(&cell->bios);
325
326 if (cell->shared_count) {
327 cell->exclusive_lock = false;
328 return false;
329 }
330
331 rb_erase(&cell->node, &prison->cells);
332 return true;
333}
334
335bool dm_cell_unlock_v2(struct dm_bio_prison_v2 *prison,
336 struct dm_bio_prison_cell_v2 *cell,
337 struct bio_list *bios)
338{
339 bool r;
340
341 spin_lock_irq(&prison->lock);
342 r = __unlock(prison, cell, bios);
343 spin_unlock_irq(&prison->lock);
344
345 return r;
346}
347EXPORT_SYMBOL_GPL(dm_cell_unlock_v2);
348
349
350
351int __init dm_bio_prison_init_v2(void)
352{
353 _cell_cache = KMEM_CACHE(dm_bio_prison_cell_v2, 0);
354 if (!_cell_cache)
355 return -ENOMEM;
356
357 return 0;
358}
359
360void dm_bio_prison_exit_v2(void)
361{
362 kmem_cache_destroy(_cell_cache);
363 _cell_cache = NULL;
364}
365
