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authorLinus Torvalds <torvalds@linux-foundation.org>2011-04-23 22:32:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-04-23 22:32:03 -0700
commitb07ad9967f40b164af77205027352ba53729cf5a (patch)
tree33ce9c53602f1983cff5dd5f209bb668fb7ffca5
parent0f1d9f78ce41a8874d30271ef8480e6f8f7f1fce (diff)
downloadlinux-b07ad9967f40b164af77205027352ba53729cf5a.tar.gz
vfs: get rid of 'struct dcache_hash_bucket' abstraction
It's a useless abstraction for 'hlist_bl_head', and it doesn't actually help anything - quite the reverse. All the users end up having to know about the hlist_bl_head details anyway, using 'struct hlist_bl_node *' etc. So it just makes the code look confusing. And the cost of it is extra '&b->head' syntactic noise, but more importantly it spuriously makes the hash table dentry list look different from the per-superblock DCACHE_DISCONNECTED dentry list. As a result, the code ended up using ad-hoc locking for one case and special helper functions for what is really another totally identical case in the very same function. Make it all look and work the same. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/dcache.c45
1 files changed, 21 insertions, 24 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 129a3573099..7108c15685d 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -99,12 +99,9 @@ static struct kmem_cache *dentry_cache __read_mostly;
static unsigned int d_hash_mask __read_mostly;
static unsigned int d_hash_shift __read_mostly;
-struct dcache_hash_bucket {
- struct hlist_bl_head head;
-};
-static struct dcache_hash_bucket *dentry_hashtable __read_mostly;
+static struct hlist_bl_head *dentry_hashtable __read_mostly;
-static inline struct dcache_hash_bucket *d_hash(struct dentry *parent,
+static inline struct hlist_bl_head *d_hash(struct dentry *parent,
unsigned long hash)
{
hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
@@ -112,14 +109,14 @@ static inline struct dcache_hash_bucket *d_hash(struct dentry *parent,
return dentry_hashtable + (hash & D_HASHMASK);
}
-static inline void spin_lock_bucket(struct dcache_hash_bucket *b)
+static inline void spin_lock_bucket(struct hlist_bl_head *b)
{
- bit_spin_lock(0, (unsigned long *)&b->head.first);
+ bit_spin_lock(0, (unsigned long *)&b->first);
}
-static inline void spin_unlock_bucket(struct dcache_hash_bucket *b)
+static inline void spin_unlock_bucket(struct hlist_bl_head *b)
{
- __bit_spin_unlock(0, (unsigned long *)&b->head.first);
+ __bit_spin_unlock(0, (unsigned long *)&b->first);
}
/* Statistics gathering. */
@@ -331,15 +328,15 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
void __d_drop(struct dentry *dentry)
{
if (!(dentry->d_flags & DCACHE_UNHASHED)) {
+ struct hlist_bl_head *b;
if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) {
- bit_spin_lock(0,
- (unsigned long *)&dentry->d_sb->s_anon.first);
+ b = &dentry->d_sb->s_anon;
+ spin_lock_bucket(b);
dentry->d_flags |= DCACHE_UNHASHED;
hlist_bl_del_init(&dentry->d_hash);
- __bit_spin_unlock(0,
- (unsigned long *)&dentry->d_sb->s_anon.first);
+ spin_unlock_bucket(b);
} else {
- struct dcache_hash_bucket *b;
+ struct hlist_bl_head *b;
b = d_hash(dentry->d_parent, dentry->d_name.hash);
spin_lock_bucket(b);
/*
@@ -1789,7 +1786,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
unsigned int len = name->len;
unsigned int hash = name->hash;
const unsigned char *str = name->name;
- struct dcache_hash_bucket *b = d_hash(parent, hash);
+ struct hlist_bl_head *b = d_hash(parent, hash);
struct hlist_bl_node *node;
struct dentry *dentry;
@@ -1813,7 +1810,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
*
* See Documentation/filesystems/path-lookup.txt for more details.
*/
- hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
+ hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
struct inode *i;
const char *tname;
int tlen;
@@ -1908,7 +1905,7 @@ struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
unsigned int len = name->len;
unsigned int hash = name->hash;
const unsigned char *str = name->name;
- struct dcache_hash_bucket *b = d_hash(parent, hash);
+ struct hlist_bl_head *b = d_hash(parent, hash);
struct hlist_bl_node *node;
struct dentry *found = NULL;
struct dentry *dentry;
@@ -1935,7 +1932,7 @@ struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
*/
rcu_read_lock();
- hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
+ hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
const char *tname;
int tlen;
@@ -2086,12 +2083,12 @@ again:
}
EXPORT_SYMBOL(d_delete);
-static void __d_rehash(struct dentry * entry, struct dcache_hash_bucket *b)
+static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b)
{
BUG_ON(!d_unhashed(entry));
spin_lock_bucket(b);
entry->d_flags &= ~DCACHE_UNHASHED;
- hlist_bl_add_head_rcu(&entry->d_hash, &b->head);
+ hlist_bl_add_head_rcu(&entry->d_hash, b);
spin_unlock_bucket(b);
}
@@ -3025,7 +3022,7 @@ static void __init dcache_init_early(void)
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
- sizeof(struct dcache_hash_bucket),
+ sizeof(struct hlist_bl_head),
dhash_entries,
13,
HASH_EARLY,
@@ -3034,7 +3031,7 @@ static void __init dcache_init_early(void)
0);
for (loop = 0; loop < (1 << d_hash_shift); loop++)
- INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
+ INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
}
static void __init dcache_init(void)
@@ -3057,7 +3054,7 @@ static void __init dcache_init(void)
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
- sizeof(struct dcache_hash_bucket),
+ sizeof(struct hlist_bl_head),
dhash_entries,
13,
0,
@@ -3066,7 +3063,7 @@ static void __init dcache_init(void)
0);
for (loop = 0; loop < (1 << d_hash_shift); loop++)
- INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
+ INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
}
/* SLAB cache for __getname() consumers */