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freebsd/sys/dev/drm/drm_hashtab.c
Robert Noland 05d841b38b Address some WITNESS panics that occur when using the via driver.
Some of these cases should be safe in a non-atomic fashion, however
since all of the driver ioctls are locked, a lot of work is required to
fix it correctly.  Just don't sleep now.

MFC after:	2 weeks
2010-04-23 14:48:30 +00:00

182 lines
4.7 KiB
C

/**************************************************************************
*
* Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*
**************************************************************************/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Simple open hash tab implementation.
*
* Authors:
* Thomas Hellström <thomas-at-tungstengraphics-dot-com>
*/
#include "dev/drm/drmP.h"
#include "dev/drm/drm_hashtab.h"
#include <sys/hash.h>
int drm_ht_create(struct drm_open_hash *ht, unsigned int order)
{
ht->size = 1 << order;
ht->order = order;
ht->table = NULL;
ht->table = hashinit_flags(ht->size, DRM_MEM_HASHTAB, &ht->mask,
HASH_NOWAIT);
if (!ht->table) {
DRM_ERROR("Out of memory for hash table\n");
return -ENOMEM;
}
return 0;
}
void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key)
{
struct drm_hash_item *entry;
struct drm_hash_item_list *h_list;
unsigned int hashed_key;
int count = 0;
hashed_key = hash32_buf(&key, sizeof(key), ht->order);
DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key);
h_list = &ht->table[hashed_key & ht->mask];
LIST_FOREACH(entry, h_list, head)
DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key);
}
static struct drm_hash_item *
drm_ht_find_key(struct drm_open_hash *ht, unsigned long key)
{
struct drm_hash_item *entry;
struct drm_hash_item_list *h_list;
unsigned int hashed_key;
hashed_key = hash32_buf(&key, sizeof(key), ht->order);
h_list = &ht->table[hashed_key & ht->mask];
LIST_FOREACH(entry, h_list, head) {
if (entry->key == key)
return entry;
if (entry->key > key)
break;
}
return NULL;
}
int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item)
{
struct drm_hash_item *entry, *parent;
struct drm_hash_item_list *h_list;
unsigned int hashed_key;
unsigned long key = item->key;
hashed_key = hash32_buf(&key, sizeof(key), ht->order);
h_list = &ht->table[hashed_key & ht->mask];
parent = NULL;
LIST_FOREACH(entry, h_list, head) {
if (entry->key == key)
return -EINVAL;
if (entry->key > key)
break;
parent = entry;
}
if (parent) {
LIST_INSERT_AFTER(parent, item, head);
} else {
LIST_INSERT_HEAD(h_list, item, head);
}
return 0;
}
/*
* Just insert an item and return any "bits" bit key that hasn't been
* used before.
*/
int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
unsigned long seed, int bits, int shift,
unsigned long add)
{
int ret;
unsigned long mask = (1 << bits) - 1;
unsigned long first, unshifted_key = 0;
unshifted_key = hash32_buf(&seed, sizeof(seed), unshifted_key);
first = unshifted_key;
do {
item->key = (unshifted_key << shift) + add;
ret = drm_ht_insert_item(ht, item);
if (ret)
unshifted_key = (unshifted_key + 1) & mask;
} while(ret && (unshifted_key != first));
if (ret) {
DRM_ERROR("Available key bit space exhausted\n");
return -EINVAL;
}
return 0;
}
int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key,
struct drm_hash_item **item)
{
struct drm_hash_item *entry;
entry = drm_ht_find_key(ht, key);
if (!entry)
return -EINVAL;
*item = entry;
return 0;
}
int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key)
{
struct drm_hash_item *entry;
entry = drm_ht_find_key(ht, key);
if (entry) {
LIST_REMOVE(entry, head);
return 0;
}
return -EINVAL;
}
int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item)
{
LIST_REMOVE(item, head);
return 0;
}
void drm_ht_remove(struct drm_open_hash *ht)
{
if (ht->table) {
hashdestroy(ht->table, DRM_MEM_HASHTAB, ht->mask);
ht->table = NULL;
}
}