2023-12-06 06:06:54

by Dave Chinner

Subject: [PATCH 06/11] vfs: factor out inode hash head calculation

From: Dave Chinner <[email protected]>

In preparation for changing the inode hash table implementation.

Signed-off-by: Dave Chinner <[email protected]>
---
fs/inode.c | 44 +++++++++++++++++++++++++-------------------
1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 3426691fa305..fead81550cf4 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -59,6 +59,22 @@ static unsigned int i_hash_shift __ro_after_init;
static struct hlist_head *inode_hashtable __ro_after_init;
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);

+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+ unsigned long tmp;
+
+ tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+ L1_CACHE_BYTES;
+ tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
+ return tmp & i_hash_mask;
+}
+
+static inline struct hlist_head *i_hash_head(struct super_block *sb,
+ unsigned int hashval)
+{
+ return inode_hashtable + hash(sb, hashval);
+}
+
/*
* Empty aops. Can be used for the cases where the user does not
* define any of the address_space operations.
@@ -502,16 +518,6 @@ static inline void inode_sb_list_del(struct inode *inode)
dlock_lists_del(&inode->i_sb_list);
}

-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
- unsigned long tmp;
-
- tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
- L1_CACHE_BYTES;
- tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
- return tmp & i_hash_mask;
-}
-
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
@@ -1187,7 +1193,7 @@ struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
+ struct hlist_head *head = i_hash_head(inode->i_sb, hashval);
struct inode *old;

again:
@@ -1291,7 +1297,7 @@ EXPORT_SYMBOL(iget5_locked);
*/
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
@@ -1359,7 +1365,7 @@ EXPORT_SYMBOL(iget_locked);
*/
static int test_inode_iunique(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *b = inode_hashtable + hash(sb, ino);
+ struct hlist_head *b = i_hash_head(sb, ino);
struct inode *inode;

hlist_for_each_entry_rcu(inode, b, i_hash) {
@@ -1446,7 +1452,7 @@ EXPORT_SYMBOL(igrab);
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_head *head = i_hash_head(sb, hashval);
struct inode *inode;

spin_lock(&inode_hash_lock);
@@ -1501,7 +1507,7 @@ EXPORT_SYMBOL(ilookup5);
*/
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
@@ -1550,7 +1556,7 @@ struct inode *find_inode_nowait(struct super_block *sb,
void *),
void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_head *head = i_hash_head(sb, hashval);
struct inode *inode, *ret_inode = NULL;
int mval;

@@ -1595,7 +1601,7 @@ EXPORT_SYMBOL(find_inode_nowait);
struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_head *head = i_hash_head(sb, hashval);
struct inode *inode;

RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
@@ -1633,7 +1639,7 @@ EXPORT_SYMBOL(find_inode_rcu);
struct inode *find_inode_by_ino_rcu(struct super_block *sb,
unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
struct inode *inode;

RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
@@ -1653,7 +1659,7 @@ int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);

while (1) {
struct inode *old = NULL;
--
2.42.0

2023-12-07 03:02:40

by Al Viro

Subject: Re: [PATCH 06/11] vfs: factor out inode hash head calculation

On Wed, Dec 06, 2023 at 05:05:35PM +1100, Dave Chinner wrote:
> From: Dave Chinner <[email protected]>
>
> In preparation for changing the inode hash table implementation.
>
> Signed-off-by: Dave Chinner <[email protected]>

ACKed-by: Al Viro <[email protected]>