[PATCH] md: tidy up raid5/6 hash table code
- replace open-coded hash chain with hlist macros
- Fix hash-table size at one page - it is already quite generous, so there
will never be a need to use multiple pages, so no need for __get_free_pages
No functional change.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 9fc5048..6e4db95 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -35,12 +35,10 @@
#define STRIPE_SHIFT (PAGE_SHIFT - 9)
#define STRIPE_SECTORS (STRIPE_SIZE>>9)
#define IO_THRESHOLD 1
-#define HASH_PAGES 1
-#define HASH_PAGES_ORDER 0
-#define NR_HASH (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *))
+#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
#define HASH_MASK (NR_HASH - 1)
-#define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])
+#define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
/* bio's attached to a stripe+device for I/O are linked together in bi_sector
* order without overlap. There may be several bio's per stripe+device, and
@@ -113,29 +111,21 @@
spin_unlock_irqrestore(&conf->device_lock, flags);
}
-static void remove_hash(struct stripe_head *sh)
+static inline void remove_hash(struct stripe_head *sh)
{
PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
- if (sh->hash_pprev) {
- if (sh->hash_next)
- sh->hash_next->hash_pprev = sh->hash_pprev;
- *sh->hash_pprev = sh->hash_next;
- sh->hash_pprev = NULL;
- }
+ hlist_del_init(&sh->hash);
}
-static __inline__ void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
+static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
{
- struct stripe_head **shp = &stripe_hash(conf, sh->sector);
+ struct hlist_head *hp = stripe_hash(conf, sh->sector);
PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
CHECK_DEVLOCK();
- if ((sh->hash_next = *shp) != NULL)
- (*shp)->hash_pprev = &sh->hash_next;
- *shp = sh;
- sh->hash_pprev = shp;
+ hlist_add_head(&sh->hash, hp);
}
@@ -228,10 +218,11 @@
static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector)
{
struct stripe_head *sh;
+ struct hlist_node *hn;
CHECK_DEVLOCK();
PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
- for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next)
+ hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
if (sh->sector == sector)
return sh;
PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
@@ -1835,9 +1826,8 @@
conf->mddev = mddev;
- if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL)
+ if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
goto abort;
- memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE);
spin_lock_init(&conf->device_lock);
init_waitqueue_head(&conf->wait_for_stripe);
@@ -1972,9 +1962,7 @@
abort:
if (conf) {
print_raid5_conf(conf);
- if (conf->stripe_hashtbl)
- free_pages((unsigned long) conf->stripe_hashtbl,
- HASH_PAGES_ORDER);
+ kfree(conf->stripe_hashtbl);
kfree(conf);
}
mddev->private = NULL;
@@ -1991,7 +1979,7 @@
md_unregister_thread(mddev->thread);
mddev->thread = NULL;
shrink_stripes(conf);
- free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);
+ kfree(conf->stripe_hashtbl);
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
kfree(conf);
@@ -2019,12 +2007,12 @@
static void printall (raid5_conf_t *conf)
{
struct stripe_head *sh;
+ struct hlist_node *hn;
int i;
spin_lock_irq(&conf->device_lock);
for (i = 0; i < NR_HASH; i++) {
- sh = conf->stripe_hashtbl[i];
- for (; sh; sh = sh->hash_next) {
+ hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
if (sh->raid_conf != conf)
continue;
print_sh(sh);