299 lines
7.0 KiB
C
299 lines
7.0 KiB
C
/**************************************************************************
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*
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* Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*
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**************************************************************************/
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/*
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* Generic simple memory manager implementation. Intended to be used as a base
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* class implementation for more advanced memory managers.
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*
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* Note that the algorithm used is quite simple and there might be substantial
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* performance gains if a smarter free list is implemented. Currently it is just an
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* unordered stack of free regions. This could easily be improved if an RB-tree
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* is used instead. At least if we expect heavy fragmentation.
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*
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* Aligned allocations can also see improvement.
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*
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* Authors:
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* Thomas Hellström <thomas-at-tungstengraphics-dot-com>
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*/
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#include "drmP.h"
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#include <linux/slab.h>
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unsigned long drm_mm_tail_space(drm_mm_t *mm)
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{
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struct list_head *tail_node;
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drm_mm_node_t *entry;
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tail_node = mm->ml_entry.prev;
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entry = list_entry(tail_node, drm_mm_node_t, ml_entry);
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if (!entry->free)
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return 0;
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return entry->size;
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}
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int drm_mm_remove_space_from_tail(drm_mm_t *mm, unsigned long size)
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{
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struct list_head *tail_node;
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drm_mm_node_t *entry;
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tail_node = mm->ml_entry.prev;
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entry = list_entry(tail_node, drm_mm_node_t, ml_entry);
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if (!entry->free)
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return -ENOMEM;
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if (entry->size <= size)
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return -ENOMEM;
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entry->size -= size;
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return 0;
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}
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static int drm_mm_create_tail_node(drm_mm_t *mm,
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unsigned long start,
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unsigned long size)
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{
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drm_mm_node_t *child;
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child = (drm_mm_node_t *)
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drm_alloc(sizeof(*child), DRM_MEM_MM);
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if (!child)
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return -ENOMEM;
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child->free = 1;
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child->size = size;
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child->start = start;
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child->mm = mm;
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list_add_tail(&child->ml_entry, &mm->ml_entry);
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list_add_tail(&child->fl_entry, &mm->fl_entry);
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return 0;
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}
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int drm_mm_add_space_to_tail(drm_mm_t *mm, unsigned long size)
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{
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struct list_head *tail_node;
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drm_mm_node_t *entry;
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tail_node = mm->ml_entry.prev;
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entry = list_entry(tail_node, drm_mm_node_t, ml_entry);
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if (!entry->free) {
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return drm_mm_create_tail_node(mm, entry->start + entry->size, size);
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}
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entry->size += size;
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return 0;
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}
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static drm_mm_node_t *drm_mm_split_at_start(drm_mm_node_t *parent,
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unsigned long size)
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{
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drm_mm_node_t *child;
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child = (drm_mm_node_t *)
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drm_alloc(sizeof(*child), DRM_MEM_MM);
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if (!child)
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return NULL;
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INIT_LIST_HEAD(&child->fl_entry);
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child->free = 0;
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child->size = size;
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child->start = parent->start;
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child->mm = parent->mm;
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list_add_tail(&child->ml_entry, &parent->ml_entry);
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INIT_LIST_HEAD(&child->fl_entry);
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parent->size -= size;
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parent->start += size;
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return child;
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}
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drm_mm_node_t *drm_mm_get_block(drm_mm_node_t * parent,
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unsigned long size, unsigned alignment)
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{
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drm_mm_node_t *align_splitoff = NULL;
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drm_mm_node_t *child;
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unsigned tmp = 0;
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if (alignment)
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tmp = parent->start % alignment;
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if (tmp) {
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align_splitoff = drm_mm_split_at_start(parent, alignment - tmp);
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if (!align_splitoff)
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return NULL;
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}
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if (parent->size == size) {
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list_del_init(&parent->fl_entry);
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parent->free = 0;
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return parent;
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} else {
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child = drm_mm_split_at_start(parent, size);
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}
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if (align_splitoff)
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drm_mm_put_block(align_splitoff);
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return child;
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}
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/*
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* Put a block. Merge with the previous and / or next block if they are free.
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* Otherwise add to the free stack.
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*/
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void drm_mm_put_block(drm_mm_node_t * cur)
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{
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drm_mm_t *mm = cur->mm;
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struct list_head *cur_head = &cur->ml_entry;
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struct list_head *root_head = &mm->ml_entry;
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drm_mm_node_t *prev_node = NULL;
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drm_mm_node_t *next_node;
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int merged = 0;
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if (cur_head->prev != root_head) {
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prev_node = list_entry(cur_head->prev, drm_mm_node_t, ml_entry);
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if (prev_node->free) {
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prev_node->size += cur->size;
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merged = 1;
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}
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}
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if (cur_head->next != root_head) {
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next_node = list_entry(cur_head->next, drm_mm_node_t, ml_entry);
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if (next_node->free) {
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if (merged) {
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prev_node->size += next_node->size;
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list_del(&next_node->ml_entry);
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list_del(&next_node->fl_entry);
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drm_free(next_node, sizeof(*next_node),
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DRM_MEM_MM);
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} else {
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next_node->size += cur->size;
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next_node->start = cur->start;
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merged = 1;
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}
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}
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}
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if (!merged) {
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cur->free = 1;
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list_add(&cur->fl_entry, &mm->fl_entry);
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} else {
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list_del(&cur->ml_entry);
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drm_free(cur, sizeof(*cur), DRM_MEM_MM);
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}
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}
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drm_mm_node_t *drm_mm_search_free(const drm_mm_t * mm,
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unsigned long size,
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unsigned alignment, int best_match)
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{
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struct list_head *list;
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const struct list_head *free_stack = &mm->fl_entry;
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drm_mm_node_t *entry;
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drm_mm_node_t *best;
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unsigned long best_size;
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unsigned wasted;
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best = NULL;
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best_size = ~0UL;
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list_for_each(list, free_stack) {
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entry = list_entry(list, drm_mm_node_t, fl_entry);
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wasted = 0;
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if (entry->size < size)
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continue;
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if (alignment) {
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register unsigned tmp = entry->start % alignment;
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if (tmp)
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wasted += alignment - tmp;
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}
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if (entry->size >= size + wasted) {
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if (!best_match)
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return entry;
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if (size < best_size) {
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best = entry;
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best_size = entry->size;
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}
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}
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}
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return best;
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}
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int drm_mm_clean(drm_mm_t * mm)
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{
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struct list_head *head = &mm->ml_entry;
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return (head->next->next == head);
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}
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int drm_mm_init(drm_mm_t * mm, unsigned long start, unsigned long size)
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{
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INIT_LIST_HEAD(&mm->ml_entry);
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INIT_LIST_HEAD(&mm->fl_entry);
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return drm_mm_create_tail_node(mm, start, size);
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}
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EXPORT_SYMBOL(drm_mm_init);
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void drm_mm_takedown(drm_mm_t * mm)
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{
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struct list_head *bnode = mm->fl_entry.next;
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drm_mm_node_t *entry;
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entry = list_entry(bnode, drm_mm_node_t, fl_entry);
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if (entry->ml_entry.next != &mm->ml_entry ||
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entry->fl_entry.next != &mm->fl_entry) {
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DRM_ERROR("Memory manager not clean. Delaying takedown\n");
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return;
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}
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list_del(&entry->fl_entry);
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list_del(&entry->ml_entry);
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drm_free(entry, sizeof(*entry), DRM_MEM_MM);
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}
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EXPORT_SYMBOL(drm_mm_takedown);
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