1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Red Hat, Inc.
5 * This file is released under the GPL.
9 #include "dm-bio-prison-v1.h"
10 #include "dm-bio-prison-v2.h"
12 #include <linux/spinlock.h>
13 #include <linux/mempool.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
17 /*----------------------------------------------------------------*/
19 #define MIN_CELLS 1024
21 struct dm_bio_prison {
27 static struct kmem_cache *_cell_cache;
29 /*----------------------------------------------------------------*/
32 * @nr_cells should be the number of cells you want in use _concurrently_.
33 * Don't confuse it with the number of distinct keys.
35 struct dm_bio_prison *dm_bio_prison_create(void)
37 struct dm_bio_prison *prison = kzalloc(sizeof(*prison), GFP_KERNEL);
43 spin_lock_init(&prison->lock);
45 ret = mempool_init_slab_pool(&prison->cell_pool, MIN_CELLS, _cell_cache);
51 prison->cells = RB_ROOT;
55 EXPORT_SYMBOL_GPL(dm_bio_prison_create);
57 void dm_bio_prison_destroy(struct dm_bio_prison *prison)
59 mempool_exit(&prison->cell_pool);
62 EXPORT_SYMBOL_GPL(dm_bio_prison_destroy);
64 struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison, gfp_t gfp)
66 return mempool_alloc(&prison->cell_pool, gfp);
68 EXPORT_SYMBOL_GPL(dm_bio_prison_alloc_cell);
70 void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
71 struct dm_bio_prison_cell *cell)
73 mempool_free(cell, &prison->cell_pool);
75 EXPORT_SYMBOL_GPL(dm_bio_prison_free_cell);
77 static void __setup_new_cell(struct dm_cell_key *key,
79 struct dm_bio_prison_cell *cell)
81 memcpy(&cell->key, key, sizeof(cell->key));
82 cell->holder = holder;
83 bio_list_init(&cell->bios);
86 static int cmp_keys(struct dm_cell_key *lhs,
87 struct dm_cell_key *rhs)
89 if (lhs->virtual < rhs->virtual)
92 if (lhs->virtual > rhs->virtual)
95 if (lhs->dev < rhs->dev)
98 if (lhs->dev > rhs->dev)
101 if (lhs->block_end <= rhs->block_begin)
104 if (lhs->block_begin >= rhs->block_end)
110 static int __bio_detain(struct dm_bio_prison *prison,
111 struct dm_cell_key *key,
113 struct dm_bio_prison_cell *cell_prealloc,
114 struct dm_bio_prison_cell **cell_result)
117 struct rb_node **new = &prison->cells.rb_node, *parent = NULL;
120 struct dm_bio_prison_cell *cell =
121 rb_entry(*new, struct dm_bio_prison_cell, node);
123 r = cmp_keys(key, &cell->key);
127 new = &((*new)->rb_left);
129 new = &((*new)->rb_right);
132 bio_list_add(&cell->bios, inmate);
138 __setup_new_cell(key, inmate, cell_prealloc);
139 *cell_result = cell_prealloc;
141 rb_link_node(&cell_prealloc->node, parent, new);
142 rb_insert_color(&cell_prealloc->node, &prison->cells);
147 static int bio_detain(struct dm_bio_prison *prison,
148 struct dm_cell_key *key,
150 struct dm_bio_prison_cell *cell_prealloc,
151 struct dm_bio_prison_cell **cell_result)
155 spin_lock_irq(&prison->lock);
156 r = __bio_detain(prison, key, inmate, cell_prealloc, cell_result);
157 spin_unlock_irq(&prison->lock);
162 int dm_bio_detain(struct dm_bio_prison *prison,
163 struct dm_cell_key *key,
165 struct dm_bio_prison_cell *cell_prealloc,
166 struct dm_bio_prison_cell **cell_result)
168 return bio_detain(prison, key, inmate, cell_prealloc, cell_result);
170 EXPORT_SYMBOL_GPL(dm_bio_detain);
172 int dm_get_cell(struct dm_bio_prison *prison,
173 struct dm_cell_key *key,
174 struct dm_bio_prison_cell *cell_prealloc,
175 struct dm_bio_prison_cell **cell_result)
177 return bio_detain(prison, key, NULL, cell_prealloc, cell_result);
179 EXPORT_SYMBOL_GPL(dm_get_cell);
182 * @inmates must have been initialised prior to this call
184 static void __cell_release(struct dm_bio_prison *prison,
185 struct dm_bio_prison_cell *cell,
186 struct bio_list *inmates)
188 rb_erase(&cell->node, &prison->cells);
192 bio_list_add(inmates, cell->holder);
193 bio_list_merge(inmates, &cell->bios);
197 void dm_cell_release(struct dm_bio_prison *prison,
198 struct dm_bio_prison_cell *cell,
199 struct bio_list *bios)
201 spin_lock_irq(&prison->lock);
202 __cell_release(prison, cell, bios);
203 spin_unlock_irq(&prison->lock);
205 EXPORT_SYMBOL_GPL(dm_cell_release);
208 * Sometimes we don't want the holder, just the additional bios.
210 static void __cell_release_no_holder(struct dm_bio_prison *prison,
211 struct dm_bio_prison_cell *cell,
212 struct bio_list *inmates)
214 rb_erase(&cell->node, &prison->cells);
215 bio_list_merge(inmates, &cell->bios);
218 void dm_cell_release_no_holder(struct dm_bio_prison *prison,
219 struct dm_bio_prison_cell *cell,
220 struct bio_list *inmates)
224 spin_lock_irqsave(&prison->lock, flags);
225 __cell_release_no_holder(prison, cell, inmates);
226 spin_unlock_irqrestore(&prison->lock, flags);
228 EXPORT_SYMBOL_GPL(dm_cell_release_no_holder);
230 void dm_cell_error(struct dm_bio_prison *prison,
231 struct dm_bio_prison_cell *cell, blk_status_t error)
233 struct bio_list bios;
236 bio_list_init(&bios);
237 dm_cell_release(prison, cell, &bios);
239 while ((bio = bio_list_pop(&bios))) {
240 bio->bi_status = error;
244 EXPORT_SYMBOL_GPL(dm_cell_error);
246 void dm_cell_visit_release(struct dm_bio_prison *prison,
247 void (*visit_fn)(void *, struct dm_bio_prison_cell *),
249 struct dm_bio_prison_cell *cell)
251 spin_lock_irq(&prison->lock);
252 visit_fn(context, cell);
253 rb_erase(&cell->node, &prison->cells);
254 spin_unlock_irq(&prison->lock);
256 EXPORT_SYMBOL_GPL(dm_cell_visit_release);
258 static int __promote_or_release(struct dm_bio_prison *prison,
259 struct dm_bio_prison_cell *cell)
261 if (bio_list_empty(&cell->bios)) {
262 rb_erase(&cell->node, &prison->cells);
266 cell->holder = bio_list_pop(&cell->bios);
270 int dm_cell_promote_or_release(struct dm_bio_prison *prison,
271 struct dm_bio_prison_cell *cell)
275 spin_lock_irq(&prison->lock);
276 r = __promote_or_release(prison, cell);
277 spin_unlock_irq(&prison->lock);
281 EXPORT_SYMBOL_GPL(dm_cell_promote_or_release);
283 /*----------------------------------------------------------------*/
285 #define DEFERRED_SET_SIZE 64
287 struct dm_deferred_entry {
288 struct dm_deferred_set *ds;
290 struct list_head work_items;
293 struct dm_deferred_set {
295 unsigned int current_entry;
296 unsigned int sweeper;
297 struct dm_deferred_entry entries[DEFERRED_SET_SIZE];
300 struct dm_deferred_set *dm_deferred_set_create(void)
303 struct dm_deferred_set *ds;
305 ds = kmalloc(sizeof(*ds), GFP_KERNEL);
309 spin_lock_init(&ds->lock);
310 ds->current_entry = 0;
312 for (i = 0; i < DEFERRED_SET_SIZE; i++) {
313 ds->entries[i].ds = ds;
314 ds->entries[i].count = 0;
315 INIT_LIST_HEAD(&ds->entries[i].work_items);
320 EXPORT_SYMBOL_GPL(dm_deferred_set_create);
322 void dm_deferred_set_destroy(struct dm_deferred_set *ds)
326 EXPORT_SYMBOL_GPL(dm_deferred_set_destroy);
328 struct dm_deferred_entry *dm_deferred_entry_inc(struct dm_deferred_set *ds)
331 struct dm_deferred_entry *entry;
333 spin_lock_irqsave(&ds->lock, flags);
334 entry = ds->entries + ds->current_entry;
336 spin_unlock_irqrestore(&ds->lock, flags);
340 EXPORT_SYMBOL_GPL(dm_deferred_entry_inc);
342 static unsigned int ds_next(unsigned int index)
344 return (index + 1) % DEFERRED_SET_SIZE;
347 static void __sweep(struct dm_deferred_set *ds, struct list_head *head)
349 while ((ds->sweeper != ds->current_entry) &&
350 !ds->entries[ds->sweeper].count) {
351 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
352 ds->sweeper = ds_next(ds->sweeper);
355 if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count)
356 list_splice_init(&ds->entries[ds->sweeper].work_items, head);
359 void dm_deferred_entry_dec(struct dm_deferred_entry *entry, struct list_head *head)
363 spin_lock_irqsave(&entry->ds->lock, flags);
364 BUG_ON(!entry->count);
366 __sweep(entry->ds, head);
367 spin_unlock_irqrestore(&entry->ds->lock, flags);
369 EXPORT_SYMBOL_GPL(dm_deferred_entry_dec);
372 * Returns 1 if deferred or 0 if no pending items to delay job.
374 int dm_deferred_set_add_work(struct dm_deferred_set *ds, struct list_head *work)
377 unsigned int next_entry;
379 spin_lock_irq(&ds->lock);
380 if ((ds->sweeper == ds->current_entry) &&
381 !ds->entries[ds->current_entry].count)
384 list_add(work, &ds->entries[ds->current_entry].work_items);
385 next_entry = ds_next(ds->current_entry);
386 if (!ds->entries[next_entry].count)
387 ds->current_entry = next_entry;
389 spin_unlock_irq(&ds->lock);
393 EXPORT_SYMBOL_GPL(dm_deferred_set_add_work);
395 /*----------------------------------------------------------------*/
397 static int __init dm_bio_prison_init_v1(void)
399 _cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
406 static void dm_bio_prison_exit_v1(void)
408 kmem_cache_destroy(_cell_cache);
412 static int (*_inits[])(void) __initdata = {
413 dm_bio_prison_init_v1,
414 dm_bio_prison_init_v2,
417 static void (*_exits[])(void) = {
418 dm_bio_prison_exit_v1,
419 dm_bio_prison_exit_v2,
422 static int __init dm_bio_prison_init(void)
424 const int count = ARRAY_SIZE(_inits);
428 for (i = 0; i < count; i++) {
443 static void __exit dm_bio_prison_exit(void)
445 int i = ARRAY_SIZE(_exits);
454 module_init(dm_bio_prison_init);
455 module_exit(dm_bio_prison_exit);
457 MODULE_DESCRIPTION(DM_NAME " bio prison");
458 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
459 MODULE_LICENSE("GPL");