[PATCH v7 12/16] dm: use new hashtable implementation

Sasha Levin
2012-10-28T19:05:27Z

Switch dm to use the new hashtable implementation. This reduces the amount of
generic unrelated code in the dm.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
drivers/md/dm-snap.c | 24 +++++------------
drivers/md/persistent-data/dm-block-manager.c | 1 -
.../persistent-data/dm-persistent-data-internal.h | 19 --------------
.../md/persistent-data/dm-transaction-manager.c | 30 +++++++---------------
4 files changed, 16 insertions(+), 58 deletions(-)
delete mode 100644 drivers/md/persistent-data/dm-persistent-data-internal.h

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 223e7eb..4b19fa0 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -34,9 +34,7 @@ static const char dm_snapshot_merge_target_name[] = "snapshot-merge";
*/
#define MIN_IOS 256

-#define DM_TRACKED_CHUNK_HASH_SIZE 16
-#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
- (DM_TRACKED_CHUNK_HASH_SIZE - 1))
+#define DM_TRACKED_CHUNK_HASH_BITS 4

struct dm_exception_table {
uint32_t hash_mask;
@@ -80,7 +78,7 @@ struct dm_snapshot {
/* Chunks with outstanding reads */
spinlock_t tracked_chunk_lock;
mempool_t *tracked_chunk_pool;
- struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
+ DECLARE_HASHTABLE(tracked_chunk_hash, DM_TRACKED_CHUNK_HASH_BITS);

/* The on disk metadata handler */
struct dm_exception_store *store;
@@ -202,8 +200,7 @@ static struct dm_snap_tracked_chunk *track_chunk(struct dm_snapshot *s,
c->chunk = chunk;

spin_lock_irq(&s->tracked_chunk_lock);
- hlist_add_head(&c->node,
- &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]);
+ hash_add(s->tracked_chunk_hash, &c->node, chunk);
spin_unlock_irq(&s->tracked_chunk_lock);

return c;
@@ -215,7 +212,7 @@ static void stop_tracking_chunk(struct dm_snapshot *s,
unsigned long flags;

spin_lock_irqsave(&s->tracked_chunk_lock, flags);
- hlist_del(&c->node);
+ hash_del(&c->node);
spin_unlock_irqrestore(&s->tracked_chunk_lock, flags);

mempool_free(c, s->tracked_chunk_pool);
@@ -229,8 +226,7 @@ static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk)

spin_lock_irq(&s->tracked_chunk_lock);

- hlist_for_each_entry(c, hn,
- &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)], node) {
+ hash_for_each_possible(s->tracked_chunk_hash, c, hn, node, chunk) {
if (c->chunk == chunk) {
found = 1;
break;
@@ -1032,7 +1028,6 @@ static void stop_merge(struct dm_snapshot *s)
static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct dm_snapshot *s;
- int i;
int r = -EINVAL;
char *origin_path, *cow_path;
unsigned args_used, num_flush_requests = 1;
@@ -1127,8 +1122,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_tracked_chunk_pool;
}

- for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++)
- INIT_HLIST_HEAD(&s->tracked_chunk_hash[i]);
+ hash_init(s->tracked_chunk_hash);

spin_lock_init(&s->tracked_chunk_lock);

@@ -1252,9 +1246,6 @@ static void __handover_exceptions(struct dm_snapshot *snap_src,

static void snapshot_dtr(struct dm_target *ti)
{
-#ifdef CONFIG_DM_DEBUG
- int i;
-#endif
struct dm_snapshot *s = ti->private;
struct dm_snapshot *snap_src = NULL, *snap_dest = NULL;

@@ -1285,8 +1276,7 @@ static void snapshot_dtr(struct dm_target *ti)
smp_mb();

#ifdef CONFIG_DM_DEBUG
- for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++)
- BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i]));
+ BUG_ON(!hash_empty(s->tracked_chunk_hash));
#endif

mempool_destroy(s->tracked_chunk_pool);
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 5ba2777..31edaf13 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -4,7 +4,6 @@
* This file is released under the GPL.
*/
#include "dm-block-manager.h"
-#include "dm-persistent-data-internal.h"
#include "../dm-bufio.h"

#include <linux/crc32c.h>
diff --git a/drivers/md/persistent-data/dm-persistent-data-internal.h b/drivers/md/persistent-data/dm-persistent-data-internal.h
deleted file mode 100644
index c49e26f..0000000
--- a/drivers/md/persistent-data/dm-persistent-data-internal.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * Copyright (C) 2011 Red Hat, Inc.
- *
- * This file is released under the GPL.
- */
-
-#ifndef _DM_PERSISTENT_DATA_INTERNAL_H
-#define _DM_PERSISTENT_DATA_INTERNAL_H
-
-#include "dm-block-manager.h"
-
-static inline unsigned dm_hash_block(dm_block_t b, unsigned hash_mask)
-{
- const unsigned BIG_PRIME = 4294967291UL;
-
- return (((unsigned) b) * BIG_PRIME) & hash_mask;
-}
-
-#endif /* _PERSISTENT_DATA_INTERNAL_H */
diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c
index d247a35..9eb9417 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.c
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -7,11 +7,11 @@
#include "dm-space-map.h"
#include "dm-space-map-disk.h"
#include "dm-space-map-metadata.h"
-#include "dm-persistent-data-internal.h"

#include <linux/export.h>
#include <linux/slab.h>
#include <linux/device-mapper.h>
+#include <linux/hashtable.h>

#define DM_MSG_PREFIX "transaction manager"

@@ -25,8 +25,7 @@ struct shadow_info {
/*
* It would be nice if we scaled with the size of transaction.
*/
-#define HASH_SIZE 256
-#define HASH_MASK (HASH_SIZE - 1)
+#define DM_HASH_BITS 8

struct dm_transaction_manager {
int is_clone;
@@ -36,7 +35,7 @@ struct dm_transaction_manager {
struct dm_space_map *sm;

spinlock_t lock;
- struct hlist_head buckets[HASH_SIZE];
+ DECLARE_HASHTABLE(hash, DM_HASH_BITS);
};

/*----------------------------------------------------------------*/
@@ -44,12 +43,11 @@ struct dm_transaction_manager {
static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
{
int r = 0;
- unsigned bucket = dm_hash_block(b, HASH_MASK);
struct shadow_info *si;
struct hlist_node *n;

spin_lock(&tm->lock);
- hlist_for_each_entry(si, n, tm->buckets + bucket, hlist)
+ hash_for_each_possible(tm->hash, si, n, hlist, b)
if (si->where == b) {
r = 1;
break;
@@ -65,15 +63,13 @@ static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
*/
static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b)
{
- unsigned bucket;
struct shadow_info *si;

si = kmalloc(sizeof(*si), GFP_NOIO);
if (si) {
si->where = b;
- bucket = dm_hash_block(b, HASH_MASK);
spin_lock(&tm->lock);
- hlist_add_head(&si->hlist, tm->buckets + bucket);
+ hash_add(tm->hash, &si->hlist, b);
spin_unlock(&tm->lock);
}
}
@@ -82,18 +78,12 @@ static void wipe_shadow_table(struct dm_transaction_manager *tm)
{
struct shadow_info *si;
struct hlist_node *n, *tmp;
- struct hlist_head *bucket;
int i;

spin_lock(&tm->lock);
- for (i = 0; i < HASH_SIZE; i++) {
- bucket = tm->buckets + i;
- hlist_for_each_entry_safe(si, n, tmp, bucket, hlist)
- kfree(si);
-
- INIT_HLIST_HEAD(bucket);
- }
-
+ hash_for_each_safe(tm->hash, i, n, tmp, si, hlist)
+ kfree(si);
+ hash_init(tm->hash);
spin_unlock(&tm->lock);
}

@@ -102,7 +92,6 @@ static void wipe_shadow_table(struct dm_transaction_manager *tm)
static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
struct dm_space_map *sm)
{
- int i;
struct dm_transaction_manager *tm;

tm = kmalloc(sizeof(*tm), GFP_KERNEL);
@@ -115,8 +104,7 @@ static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
tm->sm = sm;

spin_lock_init(&tm->lock);
- for (i = 0; i < HASH_SIZE; i++)
- INIT_HLIST_HEAD(tm->buckets + i);
+ hash_init(tm->hash);

return tm;
}
--
1.7.12.4