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Add hash_list_size() and simplify slightly.

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This commit is contained in:
rmind 2012-06-05 20:51:36 +00:00
parent 6ebd147b51
commit 533522e2c8
1 changed files with 64 additions and 71 deletions
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135
sys/kern/subr_hash.c
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@ -1,4 +1,4 @@
/* $NetBSD: subr_hash.c,v 1.4 2011/12/25 02:23:09 christos Exp $ */
/* $NetBSD: subr_hash.c,v 1.5 2012/06/05 20:51:36 rmind Exp $ */
/*
* Copyright (c) 1982, 1986, 1991, 1993
@ -37,81 +37,14 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_hash.c,v 1.4 2011/12/25 02:23:09 christos Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_hash.c,v 1.5 2012/06/05 20:51:36 rmind Exp $");
#include <sys/param.h>
#include <sys/kmem.h>
#include <sys/systm.h>
/*
* General routine to allocate a hash table.
* Allocate enough memory to hold at least `elements' list-head pointers.
* Return a pointer to the allocated space and set *hashmask to a pattern
* suitable for masking a value to use as an index into the returned array.
*/
void *
hashinit(u_int elements, enum hashtype htype, bool waitok, u_long *hashmask)
{
u_long hashsize, i;
LIST_HEAD(, generic) *hashtbl_list;
SLIST_HEAD(, generic) *hashtbl_slist;
TAILQ_HEAD(, generic) *hashtbl_tailq;
size_t esize;
void *p;
if (elements == 0)
panic("hashinit: bad cnt");
#define MAXELEMENTS (1U << ((sizeof(elements) * NBBY) - 1))
if (elements > MAXELEMENTS)
elements = MAXELEMENTS;
for (hashsize = 1; hashsize < elements; hashsize <<= 1)
continue;
switch (htype) {
case HASH_LIST:
esize = sizeof(*hashtbl_list);
break;
case HASH_SLIST:
esize = sizeof(*hashtbl_slist);
break;
case HASH_TAILQ:
esize = sizeof(*hashtbl_tailq);
break;
default:
panic("hashinit: invalid table type");
}
p = kmem_alloc(hashsize * esize, (waitok ? KM_SLEEP : KM_NOSLEEP));
if (p == NULL)
return (NULL);
switch (htype) {
case HASH_LIST:
hashtbl_list = p;
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl_list[i]);
break;
case HASH_SLIST:
hashtbl_slist = p;
for (i = 0; i < hashsize; i++)
SLIST_INIT(&hashtbl_slist[i]);
break;
case HASH_TAILQ:
hashtbl_tailq = p;
for (i = 0; i < hashsize; i++)
TAILQ_INIT(&hashtbl_tailq[i]);
break;
}
*hashmask = hashsize - 1;
return (p);
}
/*
* Free memory from hash table previosly allocated via hashinit().
*/
void
hashdone(void *hashtbl, enum hashtype htype, u_long hashmask)
static size_t
hash_list_size(enum hashtype htype)
{
LIST_HEAD(, generic) *hashtbl_list;
SLIST_HEAD(, generic) *hashtbl_slist;
@ -131,6 +64,66 @@ hashdone(void *hashtbl, enum hashtype htype, u_long hashmask)
default:
panic("hashdone: invalid table type");
}
return esize;
}
/*
* General routine to allocate a hash table.
* Allocate enough memory to hold at least `elements' list-head pointers.
* Return a pointer to the allocated space and set *hashmask to a pattern
* suitable for masking a value to use as an index into the returned array.
*/
void *
hashinit(u_int elements, enum hashtype htype, bool waitok, u_long *hashmask)
{
LIST_HEAD(, generic) *hashtbl_list;
SLIST_HEAD(, generic) *hashtbl_slist;
TAILQ_HEAD(, generic) *hashtbl_tailq;
u_long hashsize, i;
size_t esize;
void *p;
KASSERT(elements > 0);
#define MAXELEMENTS (1U << ((sizeof(elements) * NBBY) - 1))
if (elements > MAXELEMENTS)
elements = MAXELEMENTS;
for (hashsize = 1; hashsize < elements; hashsize <<= 1)
continue;
esize = hash_list_size(htype);
p = kmem_alloc(hashsize * esize, waitok ? KM_SLEEP : KM_NOSLEEP);
if (p == NULL)
return NULL;
switch (htype) {
case HASH_LIST:
hashtbl_list = p;
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl_list[i]);
break;
case HASH_SLIST:
hashtbl_slist = p;
for (i = 0; i < hashsize; i++)
SLIST_INIT(&hashtbl_slist[i]);
break;
case HASH_TAILQ:
hashtbl_tailq = p;
for (i = 0; i < hashsize; i++)
TAILQ_INIT(&hashtbl_tailq[i]);
break;
}
*hashmask = hashsize - 1;
return p;
}
/*
* Free memory from hash table previosly allocated via hashinit().
*/
void
hashdone(void *hashtbl, enum hashtype htype, u_long hashmask)
{
const size_t esize = hash_list_size(htype);
kmem_free(hashtbl, esize * (hashmask + 1));
}