460 lines
10 KiB
C
460 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2012 Red Hat, Inc.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include "dm.h"
|
|
#include "dm-bio-prison-v1.h"
|
|
#include "dm-bio-prison-v2.h"
|
|
|
|
#include <linux/spinlock.h>
|
|
#include <linux/mempool.h>
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
#define MIN_CELLS 1024
|
|
|
|
struct dm_bio_prison {
|
|
spinlock_t lock;
|
|
struct rb_root cells;
|
|
mempool_t cell_pool;
|
|
};
|
|
|
|
static struct kmem_cache *_cell_cache;
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
/*
|
|
* @nr_cells should be the number of cells you want in use _concurrently_.
|
|
* Don't confuse it with the number of distinct keys.
|
|
*/
|
|
struct dm_bio_prison *dm_bio_prison_create(void)
|
|
{
|
|
struct dm_bio_prison *prison = kzalloc(sizeof(*prison), GFP_KERNEL);
|
|
int ret;
|
|
|
|
if (!prison)
|
|
return NULL;
|
|
|
|
spin_lock_init(&prison->lock);
|
|
|
|
ret = mempool_init_slab_pool(&prison->cell_pool, MIN_CELLS, _cell_cache);
|
|
if (ret) {
|
|
kfree(prison);
|
|
return NULL;
|
|
}
|
|
|
|
prison->cells = RB_ROOT;
|
|
|
|
return prison;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_bio_prison_create);
|
|
|
|
void dm_bio_prison_destroy(struct dm_bio_prison *prison)
|
|
{
|
|
mempool_exit(&prison->cell_pool);
|
|
kfree(prison);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_bio_prison_destroy);
|
|
|
|
struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison, gfp_t gfp)
|
|
{
|
|
return mempool_alloc(&prison->cell_pool, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_bio_prison_alloc_cell);
|
|
|
|
void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
mempool_free(cell, &prison->cell_pool);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_bio_prison_free_cell);
|
|
|
|
static void __setup_new_cell(struct dm_cell_key *key,
|
|
struct bio *holder,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
memcpy(&cell->key, key, sizeof(cell->key));
|
|
cell->holder = holder;
|
|
bio_list_init(&cell->bios);
|
|
}
|
|
|
|
static int cmp_keys(struct dm_cell_key *lhs,
|
|
struct dm_cell_key *rhs)
|
|
{
|
|
if (lhs->virtual < rhs->virtual)
|
|
return -1;
|
|
|
|
if (lhs->virtual > rhs->virtual)
|
|
return 1;
|
|
|
|
if (lhs->dev < rhs->dev)
|
|
return -1;
|
|
|
|
if (lhs->dev > rhs->dev)
|
|
return 1;
|
|
|
|
if (lhs->block_end <= rhs->block_begin)
|
|
return -1;
|
|
|
|
if (lhs->block_begin >= rhs->block_end)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __bio_detain(struct dm_bio_prison *prison,
|
|
struct dm_cell_key *key,
|
|
struct bio *inmate,
|
|
struct dm_bio_prison_cell *cell_prealloc,
|
|
struct dm_bio_prison_cell **cell_result)
|
|
{
|
|
int r;
|
|
struct rb_node **new = &prison->cells.rb_node, *parent = NULL;
|
|
|
|
while (*new) {
|
|
struct dm_bio_prison_cell *cell =
|
|
rb_entry(*new, struct dm_bio_prison_cell, node);
|
|
|
|
r = cmp_keys(key, &cell->key);
|
|
|
|
parent = *new;
|
|
if (r < 0)
|
|
new = &((*new)->rb_left);
|
|
else if (r > 0)
|
|
new = &((*new)->rb_right);
|
|
else {
|
|
if (inmate)
|
|
bio_list_add(&cell->bios, inmate);
|
|
*cell_result = cell;
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
__setup_new_cell(key, inmate, cell_prealloc);
|
|
*cell_result = cell_prealloc;
|
|
|
|
rb_link_node(&cell_prealloc->node, parent, new);
|
|
rb_insert_color(&cell_prealloc->node, &prison->cells);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bio_detain(struct dm_bio_prison *prison,
|
|
struct dm_cell_key *key,
|
|
struct bio *inmate,
|
|
struct dm_bio_prison_cell *cell_prealloc,
|
|
struct dm_bio_prison_cell **cell_result)
|
|
{
|
|
int r;
|
|
|
|
spin_lock_irq(&prison->lock);
|
|
r = __bio_detain(prison, key, inmate, cell_prealloc, cell_result);
|
|
spin_unlock_irq(&prison->lock);
|
|
|
|
return r;
|
|
}
|
|
|
|
int dm_bio_detain(struct dm_bio_prison *prison,
|
|
struct dm_cell_key *key,
|
|
struct bio *inmate,
|
|
struct dm_bio_prison_cell *cell_prealloc,
|
|
struct dm_bio_prison_cell **cell_result)
|
|
{
|
|
return bio_detain(prison, key, inmate, cell_prealloc, cell_result);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_bio_detain);
|
|
|
|
int dm_get_cell(struct dm_bio_prison *prison,
|
|
struct dm_cell_key *key,
|
|
struct dm_bio_prison_cell *cell_prealloc,
|
|
struct dm_bio_prison_cell **cell_result)
|
|
{
|
|
return bio_detain(prison, key, NULL, cell_prealloc, cell_result);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_get_cell);
|
|
|
|
/*
|
|
* @inmates must have been initialised prior to this call
|
|
*/
|
|
static void __cell_release(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell,
|
|
struct bio_list *inmates)
|
|
{
|
|
rb_erase(&cell->node, &prison->cells);
|
|
|
|
if (inmates) {
|
|
if (cell->holder)
|
|
bio_list_add(inmates, cell->holder);
|
|
bio_list_merge(inmates, &cell->bios);
|
|
}
|
|
}
|
|
|
|
void dm_cell_release(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell,
|
|
struct bio_list *bios)
|
|
{
|
|
spin_lock_irq(&prison->lock);
|
|
__cell_release(prison, cell, bios);
|
|
spin_unlock_irq(&prison->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_cell_release);
|
|
|
|
/*
|
|
* Sometimes we don't want the holder, just the additional bios.
|
|
*/
|
|
static void __cell_release_no_holder(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell,
|
|
struct bio_list *inmates)
|
|
{
|
|
rb_erase(&cell->node, &prison->cells);
|
|
bio_list_merge(inmates, &cell->bios);
|
|
}
|
|
|
|
void dm_cell_release_no_holder(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell,
|
|
struct bio_list *inmates)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&prison->lock, flags);
|
|
__cell_release_no_holder(prison, cell, inmates);
|
|
spin_unlock_irqrestore(&prison->lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_cell_release_no_holder);
|
|
|
|
void dm_cell_error(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell, blk_status_t error)
|
|
{
|
|
struct bio_list bios;
|
|
struct bio *bio;
|
|
|
|
bio_list_init(&bios);
|
|
dm_cell_release(prison, cell, &bios);
|
|
|
|
while ((bio = bio_list_pop(&bios))) {
|
|
bio->bi_status = error;
|
|
bio_endio(bio);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_cell_error);
|
|
|
|
void dm_cell_visit_release(struct dm_bio_prison *prison,
|
|
void (*visit_fn)(void *, struct dm_bio_prison_cell *),
|
|
void *context,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
spin_lock_irq(&prison->lock);
|
|
visit_fn(context, cell);
|
|
rb_erase(&cell->node, &prison->cells);
|
|
spin_unlock_irq(&prison->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_cell_visit_release);
|
|
|
|
static int __promote_or_release(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
if (bio_list_empty(&cell->bios)) {
|
|
rb_erase(&cell->node, &prison->cells);
|
|
return 1;
|
|
}
|
|
|
|
cell->holder = bio_list_pop(&cell->bios);
|
|
return 0;
|
|
}
|
|
|
|
int dm_cell_promote_or_release(struct dm_bio_prison *prison,
|
|
struct dm_bio_prison_cell *cell)
|
|
{
|
|
int r;
|
|
|
|
spin_lock_irq(&prison->lock);
|
|
r = __promote_or_release(prison, cell);
|
|
spin_unlock_irq(&prison->lock);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_cell_promote_or_release);
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
#define DEFERRED_SET_SIZE 64
|
|
|
|
struct dm_deferred_entry {
|
|
struct dm_deferred_set *ds;
|
|
unsigned int count;
|
|
struct list_head work_items;
|
|
};
|
|
|
|
struct dm_deferred_set {
|
|
spinlock_t lock;
|
|
unsigned int current_entry;
|
|
unsigned int sweeper;
|
|
struct dm_deferred_entry entries[DEFERRED_SET_SIZE];
|
|
};
|
|
|
|
struct dm_deferred_set *dm_deferred_set_create(void)
|
|
{
|
|
int i;
|
|
struct dm_deferred_set *ds;
|
|
|
|
ds = kmalloc(sizeof(*ds), GFP_KERNEL);
|
|
if (!ds)
|
|
return NULL;
|
|
|
|
spin_lock_init(&ds->lock);
|
|
ds->current_entry = 0;
|
|
ds->sweeper = 0;
|
|
for (i = 0; i < DEFERRED_SET_SIZE; i++) {
|
|
ds->entries[i].ds = ds;
|
|
ds->entries[i].count = 0;
|
|
INIT_LIST_HEAD(&ds->entries[i].work_items);
|
|
}
|
|
|
|
return ds;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_deferred_set_create);
|
|
|
|
void dm_deferred_set_destroy(struct dm_deferred_set *ds)
|
|
{
|
|
kfree(ds);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_deferred_set_destroy);
|
|
|
|
struct dm_deferred_entry *dm_deferred_entry_inc(struct dm_deferred_set *ds)
|
|
{
|
|
unsigned long flags;
|
|
struct dm_deferred_entry *entry;
|
|
|
|
spin_lock_irqsave(&ds->lock, flags);
|
|
entry = ds->entries + ds->current_entry;
|
|
entry->count++;
|
|
spin_unlock_irqrestore(&ds->lock, flags);
|
|
|
|
return entry;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_deferred_entry_inc);
|
|
|
|
static unsigned int ds_next(unsigned int index)
|
|
{
|
|
return (index + 1) % DEFERRED_SET_SIZE;
|
|
}
|
|
|
|
static void __sweep(struct dm_deferred_set *ds, struct list_head *head)
|
|
{
|
|
while ((ds->sweeper != ds->current_entry) &&
|
|
!ds->entries[ds->sweeper].count) {
|
|
list_splice_init(&ds->entries[ds->sweeper].work_items, head);
|
|
ds->sweeper = ds_next(ds->sweeper);
|
|
}
|
|
|
|
if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count)
|
|
list_splice_init(&ds->entries[ds->sweeper].work_items, head);
|
|
}
|
|
|
|
void dm_deferred_entry_dec(struct dm_deferred_entry *entry, struct list_head *head)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&entry->ds->lock, flags);
|
|
BUG_ON(!entry->count);
|
|
--entry->count;
|
|
__sweep(entry->ds, head);
|
|
spin_unlock_irqrestore(&entry->ds->lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_deferred_entry_dec);
|
|
|
|
/*
|
|
* Returns 1 if deferred or 0 if no pending items to delay job.
|
|
*/
|
|
int dm_deferred_set_add_work(struct dm_deferred_set *ds, struct list_head *work)
|
|
{
|
|
int r = 1;
|
|
unsigned int next_entry;
|
|
|
|
spin_lock_irq(&ds->lock);
|
|
if ((ds->sweeper == ds->current_entry) &&
|
|
!ds->entries[ds->current_entry].count)
|
|
r = 0;
|
|
else {
|
|
list_add(work, &ds->entries[ds->current_entry].work_items);
|
|
next_entry = ds_next(ds->current_entry);
|
|
if (!ds->entries[next_entry].count)
|
|
ds->current_entry = next_entry;
|
|
}
|
|
spin_unlock_irq(&ds->lock);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_deferred_set_add_work);
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
static int __init dm_bio_prison_init_v1(void)
|
|
{
|
|
_cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
|
|
if (!_cell_cache)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void dm_bio_prison_exit_v1(void)
|
|
{
|
|
kmem_cache_destroy(_cell_cache);
|
|
_cell_cache = NULL;
|
|
}
|
|
|
|
static int (*_inits[])(void) __initdata = {
|
|
dm_bio_prison_init_v1,
|
|
dm_bio_prison_init_v2,
|
|
};
|
|
|
|
static void (*_exits[])(void) = {
|
|
dm_bio_prison_exit_v1,
|
|
dm_bio_prison_exit_v2,
|
|
};
|
|
|
|
static int __init dm_bio_prison_init(void)
|
|
{
|
|
const int count = ARRAY_SIZE(_inits);
|
|
|
|
int r, i;
|
|
|
|
for (i = 0; i < count; i++) {
|
|
r = _inits[i]();
|
|
if (r)
|
|
goto bad;
|
|
}
|
|
|
|
return 0;
|
|
|
|
bad:
|
|
while (i--)
|
|
_exits[i]();
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_bio_prison_exit(void)
|
|
{
|
|
int i = ARRAY_SIZE(_exits);
|
|
|
|
while (i--)
|
|
_exits[i]();
|
|
}
|
|
|
|
/*
|
|
* module hooks
|
|
*/
|
|
module_init(dm_bio_prison_init);
|
|
module_exit(dm_bio_prison_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " bio prison");
|
|
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|