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Message-Id: <1398433668-16201-1-git-send-email-sasha.levin@oracle.com>
Date: Fri, 25 Apr 2014 09:47:48 -0400
From: Sasha Levin <sasha.levin@...cle.com>
To: viro@...iv.linux.org.uk
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
Sasha Levin <sasha.levin@...cle.com>
Subject: [PATCH] dcookies: use generic hashtable implementation
Switch dcookies to use the kernel's generic hashtable implementation
instead of a custom one. Less code, more readable and same result.
Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
fs/dcookies.c | 97 ++++++++++-----------------------------------------------
1 file changed, 16 insertions(+), 81 deletions(-)
diff --git a/fs/dcookies.c b/fs/dcookies.c
index ac44a69..65014b5 100644
--- a/fs/dcookies.c
+++ b/fs/dcookies.c
@@ -26,6 +26,7 @@
#include <linux/mutex.h>
#include <linux/path.h>
#include <linux/compat.h>
+#include <linux/hashtable.h>
#include <asm/uaccess.h>
/* The dcookies are allocated from a kmem_cache and
@@ -34,14 +35,13 @@
*/
struct dcookie_struct {
struct path path;
- struct list_head hash_list;
+ struct hlist_node hash_list;
};
static LIST_HEAD(dcookie_users);
static DEFINE_MUTEX(dcookie_mutex);
static struct kmem_cache *dcookie_cache __read_mostly;
-static struct list_head *dcookie_hashtable __read_mostly;
-static size_t hash_size __read_mostly;
+static __read_mostly DEFINE_HASHTABLE(dcookie_hashtable, 10);
static inline int is_live(void)
{
@@ -55,38 +55,21 @@ static inline unsigned long dcookie_value(struct dcookie_struct * dcs)
return (unsigned long)dcs->path.dentry;
}
-
-static size_t dcookie_hash(unsigned long dcookie)
-{
- return (dcookie >> L1_CACHE_SHIFT) & (hash_size - 1);
-}
-
-
static struct dcookie_struct * find_dcookie(unsigned long dcookie)
{
- struct dcookie_struct *found = NULL;
- struct dcookie_struct * dcs;
- struct list_head * pos;
- struct list_head * list;
+ struct dcookie_struct *dcs;
- list = dcookie_hashtable + dcookie_hash(dcookie);
+ hash_for_each_possible(dcookie_hashtable, dcs, hash_list, dcookie)
+ if (dcookie_value(dcs) == dcookie)
+ return dcs;
- list_for_each(pos, list) {
- dcs = list_entry(pos, struct dcookie_struct, hash_list);
- if (dcookie_value(dcs) == dcookie) {
- found = dcs;
- break;
- }
- }
-
- return found;
+ return NULL;
}
static void hash_dcookie(struct dcookie_struct * dcs)
{
- struct list_head * list = dcookie_hashtable + dcookie_hash(dcookie_value(dcs));
- list_add(&dcs->hash_list, list);
+ hash_add(dcookie_hashtable, &dcs->hash_list, dcookie_value(dcs));
}
@@ -216,55 +199,14 @@ COMPAT_SYSCALL_DEFINE4(lookup_dcookie, u32, w0, u32, w1, char __user *, buf, com
static int dcookie_init(void)
{
- struct list_head * d;
- unsigned int i, hash_bits;
- int err = -ENOMEM;
-
dcookie_cache = kmem_cache_create("dcookie_cache",
sizeof(struct dcookie_struct),
0, 0, NULL);
if (!dcookie_cache)
- goto out;
-
- dcookie_hashtable = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (!dcookie_hashtable)
- goto out_kmem;
+ return -ENOMEM;
- err = 0;
-
- /*
- * Find the power-of-two list-heads that can fit into the allocation..
- * We don't guarantee that "sizeof(struct list_head)" is necessarily
- * a power-of-two.
- */
- hash_size = PAGE_SIZE / sizeof(struct list_head);
- hash_bits = 0;
- do {
- hash_bits++;
- } while ((hash_size >> hash_bits) != 0);
- hash_bits--;
-
- /*
- * Re-calculate the actual number of entries and the mask
- * from the number of bits we can fit.
- */
- hash_size = 1UL << hash_bits;
-
- /* And initialize the newly allocated array */
- d = dcookie_hashtable;
- i = hash_size;
- do {
- INIT_LIST_HEAD(d);
- d++;
- i--;
- } while (i);
-
-out:
- return err;
-out_kmem:
- kmem_cache_destroy(dcookie_cache);
- goto out;
+ return 0;
}
@@ -283,22 +225,15 @@ static void free_dcookie(struct dcookie_struct * dcs)
static void dcookie_exit(void)
{
- struct list_head * list;
- struct list_head * pos;
- struct list_head * pos2;
- struct dcookie_struct * dcs;
+ struct hlist_node *pos;
+ struct dcookie_struct *dcs;
size_t i;
- for (i = 0; i < hash_size; ++i) {
- list = dcookie_hashtable + i;
- list_for_each_safe(pos, pos2, list) {
- dcs = list_entry(pos, struct dcookie_struct, hash_list);
- list_del(&dcs->hash_list);
- free_dcookie(dcs);
- }
+ hash_for_each_safe(dcookie_hashtable, i, pos, dcs, hash_list) {
+ hash_del(&dcs->hash_list);
+ free_dcookie(dcs);
}
- kfree(dcookie_hashtable);
kmem_cache_destroy(dcookie_cache);
}
--
1.7.10.4
--
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