drm_mm.c

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/**************************************************************************
 *
 * 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.
 *
 *
 **************************************************************************/

/*
 * Generic simple memory manager implementation. Intended to be used as a base
 * class implementation for more advanced memory managers.
 *
 * Note that the algorithm used is quite simple and there might be substantial
 * performance gains if a smarter free list is implemented. Currently it is just an
 * unordered stack of free regions. This could easily be improved if an RB-tree
 * is used instead. At least if we expect heavy fragmentation.
 *
 * Aligned allocations can also see improvement.
 *
 * Authors:
 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
 */

#include <drm/drmP.h>
#include <drm/drm_mm.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/export.h>

#define MM_UNUSED_TARGET 4

static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
{
    struct drm_mm_node *child;

    if (atomic)
        child = kzalloc(sizeof(*child), GFP_ATOMIC);
    else
        child = kzalloc(sizeof(*child), GFP_KERNEL);

    if (unlikely(child == NULL)) {
        spin_lock(&mm->unused_lock);
        if (list_empty(&mm->unused_nodes))
            child = NULL;
        else {
            child =
                list_entry(mm->unused_nodes.next,
                       struct drm_mm_node, node_list);
            list_del(&child->node_list);
            --mm->num_unused;
        }
        spin_unlock(&mm->unused_lock);
    }
    return child;
}

/* drm_mm_pre_get() - pre allocate drm_mm_node structure
 * drm_mm:  memory manager struct we are pre-allocating for
 *
 * Returns 0 on success or -ENOMEM if allocation fails.
 */
int drm_mm_pre_get(struct drm_mm *mm)
{
    struct drm_mm_node *node;

    spin_lock(&mm->unused_lock);
    while (mm->num_unused < MM_UNUSED_TARGET) {
        spin_unlock(&mm->unused_lock);
        node = kzalloc(sizeof(*node), GFP_KERNEL);
        spin_lock(&mm->unused_lock);

        if (unlikely(node == NULL)) {
            int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
            spin_unlock(&mm->unused_lock);
            return ret;
        }
        ++mm->num_unused;
        list_add_tail(&node->node_list, &mm->unused_nodes);
    }
    spin_unlock(&mm->unused_lock);
    return 0;
}
EXPORT_SYMBOL(drm_mm_pre_get);

static inline unsigned long drm_mm_hole_node_start(struct drm_mm_node *hole_node)
{
    return hole_node->start + hole_node->size;
}

static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
{
    struct drm_mm_node *next_node =
        list_entry(hole_node->node_list.next, struct drm_mm_node,
               node_list);

    return next_node->start;
}

static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
                 struct drm_mm_node *node,
                 unsigned long size, unsigned alignment,
                 unsigned long color)
{
    struct drm_mm *mm = hole_node->mm;
    unsigned long hole_start = drm_mm_hole_node_start(hole_node);
    unsigned long hole_end = drm_mm_hole_node_end(hole_node);
    unsigned long adj_start = hole_start;
    unsigned long adj_end = hole_end;

    BUG_ON(!hole_node->hole_follows || node->allocated);

    if (mm->color_adjust)
        mm->color_adjust(hole_node, color, &adj_start, &adj_end);

    if (alignment) {
        unsigned tmp = adj_start % alignment;
        if (tmp)
            adj_start += alignment - tmp;
    }

    if (adj_start == hole_start) {
        hole_node->hole_follows = 0;
        list_del(&hole_node->hole_stack);
    }

    node->start = adj_start;
    node->size = size;
    node->mm = mm;
    node->color = color;
    node->allocated = 1;

    INIT_LIST_HEAD(&node->hole_stack);
    list_add(&node->node_list, &hole_node->node_list);

    BUG_ON(node->start + node->size > adj_end);

    node->hole_follows = 0;
    if (node->start + node->size < hole_end) {
        list_add(&node->hole_stack, &mm->hole_stack);
        node->hole_follows = 1;
    }
}

struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *hole_node,
                         unsigned long size,
                         unsigned alignment,
                         unsigned long color,
                         int atomic)
{
    struct drm_mm_node *node;

    node = drm_mm_kmalloc(hole_node->mm, atomic);
    if (unlikely(node == NULL))
        return NULL;

    drm_mm_insert_helper(hole_node, node, size, alignment, color);

    return node;
}
EXPORT_SYMBOL(drm_mm_get_block_generic);

int drm_mm_insert_node(struct drm_mm *mm, struct drm_mm_node *node,
               unsigned long size, unsigned alignment)
{
    struct drm_mm_node *hole_node;

    hole_node = drm_mm_search_free(mm, size, alignment, false);
    if (!hole_node)
        return -ENOSPC;

    drm_mm_insert_helper(hole_node, node, size, alignment, 0);

    return 0;
}
EXPORT_SYMBOL(drm_mm_insert_node);

static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
                       struct drm_mm_node *node,
                       unsigned long size, unsigned alignment,
                       unsigned long color,
                       unsigned long start, unsigned long end)
{
    struct drm_mm *mm = hole_node->mm;
    unsigned long hole_start = drm_mm_hole_node_start(hole_node);
    unsigned long hole_end = drm_mm_hole_node_end(hole_node);
    unsigned long adj_start = hole_start;
    unsigned long adj_end = hole_end;

    BUG_ON(!hole_node->hole_follows || node->allocated);

    if (mm->color_adjust)
        mm->color_adjust(hole_node, color, &adj_start, &adj_end);

    if (adj_start < start)
        adj_start = start;

    if (alignment) {
        unsigned tmp = adj_start % alignment;
        if (tmp)
            adj_start += alignment - tmp;
    }

    if (adj_start == hole_start) {
        hole_node->hole_follows = 0;
        list_del(&hole_node->hole_stack);
    }

    node->start = adj_start;
    node->size = size;
    node->mm = mm;
    node->color = color;
    node->allocated = 1;

    INIT_LIST_HEAD(&node->hole_stack);
    list_add(&node->node_list, &hole_node->node_list);

    BUG_ON(node->start + node->size > adj_end);
    BUG_ON(node->start + node->size > end);

    node->hole_follows = 0;
    if (node->start + node->size < hole_end) {
        list_add(&node->hole_stack, &mm->hole_stack);
        node->hole_follows = 1;
    }
}

struct drm_mm_node *drm_mm_get_block_range_generic(struct drm_mm_node *hole_node,
                        unsigned long size,
                        unsigned alignment,
                        unsigned long color,
                        unsigned long start,
                        unsigned long end,
                        int atomic)
{
    struct drm_mm_node *node;

    node = drm_mm_kmalloc(hole_node->mm, atomic);
    if (unlikely(node == NULL))
        return NULL;

    drm_mm_insert_helper_range(hole_node, node, size, alignment, color,
                   start, end);

    return node;
}
EXPORT_SYMBOL(drm_mm_get_block_range_generic);

int drm_mm_insert_node_in_range(struct drm_mm *mm, struct drm_mm_node *node,
                unsigned long size, unsigned alignment,
                unsigned long start, unsigned long end)
{
    struct drm_mm_node *hole_node;

    hole_node = drm_mm_search_free_in_range(mm, size, alignment,
                        start, end, false);
    if (!hole_node)
        return -ENOSPC;

    drm_mm_insert_helper_range(hole_node, node, size, alignment, 0,
                   start, end);

    return 0;
}
EXPORT_SYMBOL(drm_mm_insert_node_in_range);

void drm_mm_remove_node(struct drm_mm_node *node)
{
    struct drm_mm *mm = node->mm;
    struct drm_mm_node *prev_node;

    BUG_ON(node->scanned_block || node->scanned_prev_free
                   || node->scanned_next_free);

    prev_node =
        list_entry(node->node_list.prev, struct drm_mm_node, node_list);

    if (node->hole_follows) {
        BUG_ON(drm_mm_hole_node_start(node)
                == drm_mm_hole_node_end(node));
        list_del(&node->hole_stack);
    } else
        BUG_ON(drm_mm_hole_node_start(node)
                != drm_mm_hole_node_end(node));

    if (!prev_node->hole_follows) {
        prev_node->hole_follows = 1;
        list_add(&prev_node->hole_stack, &mm->hole_stack);
    } else
        list_move(&prev_node->hole_stack, &mm->hole_stack);

    list_del(&node->node_list);
    node->allocated = 0;
}
EXPORT_SYMBOL(drm_mm_remove_node);

/*
 * Remove a memory node from the allocator and free the allocated struct
 * drm_mm_node. Only to be used on a struct drm_mm_node obtained by one of the
 * drm_mm_get_block functions.
 */
void drm_mm_put_block(struct drm_mm_node *node)
{

    struct drm_mm *mm = node->mm;

    drm_mm_remove_node(node);

    spin_lock(&mm->unused_lock);
    if (mm->num_unused < MM_UNUSED_TARGET) {
        list_add(&node->node_list, &mm->unused_nodes);
        ++mm->num_unused;
    } else
        kfree(node);
    spin_unlock(&mm->unused_lock);
}
EXPORT_SYMBOL(drm_mm_put_block);

static int check_free_hole(unsigned long start, unsigned long end,
               unsigned long size, unsigned alignment)
{
    if (end - start < size)
        return 0;

    if (alignment) {
        unsigned tmp = start % alignment;
        if (tmp)
            start += alignment - tmp;
    }

    return end >= start + size;
}

struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
                           unsigned long size,
                           unsigned alignment,
                           unsigned long color,
                           bool best_match)
{
    struct drm_mm_node *entry;
    struct drm_mm_node *best;
    unsigned long best_size;

    BUG_ON(mm->scanned_blocks);

    best = NULL;
    best_size = ~0UL;

    list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
        unsigned long adj_start = drm_mm_hole_node_start(entry);
        unsigned long adj_end = drm_mm_hole_node_end(entry);

        if (mm->color_adjust) {
            mm->color_adjust(entry, color, &adj_start, &adj_end);
            if (adj_end <= adj_start)
                continue;
        }

        BUG_ON(!entry->hole_follows);
        if (!check_free_hole(adj_start, adj_end, size, alignment))
            continue;

        if (!best_match)
            return entry;

        if (entry->size < best_size) {
            best = entry;
            best_size = entry->size;
        }
    }

    return best;
}
EXPORT_SYMBOL(drm_mm_search_free_generic);

struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
                            unsigned long size,
                            unsigned alignment,
                            unsigned long color,
                            unsigned long start,
                            unsigned long end,
                            bool best_match)
{
    struct drm_mm_node *entry;
    struct drm_mm_node *best;
    unsigned long best_size;

    BUG_ON(mm->scanned_blocks);

    best = NULL;
    best_size = ~0UL;

    list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
        unsigned long adj_start = drm_mm_hole_node_start(entry) < start ?
            start : drm_mm_hole_node_start(entry);
        unsigned long adj_end = drm_mm_hole_node_end(entry) > end ?
            end : drm_mm_hole_node_end(entry);

        BUG_ON(!entry->hole_follows);

        if (mm->color_adjust) {
            mm->color_adjust(entry, color, &adj_start, &adj_end);
            if (adj_end <= adj_start)
                continue;
        }

        if (!check_free_hole(adj_start, adj_end, size, alignment))
            continue;

        if (!best_match)
            return entry;

        if (entry->size < best_size) {
            best = entry;
            best_size = entry->size;
        }
    }

    return best;
}
EXPORT_SYMBOL(drm_mm_search_free_in_range_generic);

void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
{
    list_replace(&old->node_list, &new->node_list);
    list_replace(&old->hole_stack, &new->hole_stack);
    new->hole_follows = old->hole_follows;
    new->mm = old->mm;
    new->start = old->start;
    new->size = old->size;
    new->color = old->color;

    old->allocated = 0;
    new->allocated = 1;
}
EXPORT_SYMBOL(drm_mm_replace_node);

void drm_mm_init_scan(struct drm_mm *mm,
              unsigned long size,
              unsigned alignment,
              unsigned long color)
{
    mm->scan_color = color;
    mm->scan_alignment = alignment;
    mm->scan_size = size;
    mm->scanned_blocks = 0;
    mm->scan_hit_start = 0;
    mm->scan_hit_size = 0;
    mm->scan_check_range = 0;
    mm->prev_scanned_node = NULL;
}
EXPORT_SYMBOL(drm_mm_init_scan);

void drm_mm_init_scan_with_range(struct drm_mm *mm,
                 unsigned long size,
                 unsigned alignment,
                 unsigned long color,
                 unsigned long start,
                 unsigned long end)
{
    mm->scan_color = color;
    mm->scan_alignment = alignment;
    mm->scan_size = size;
    mm->scanned_blocks = 0;
    mm->scan_hit_start = 0;
    mm->scan_hit_size = 0;
    mm->scan_start = start;
    mm->scan_end = end;
    mm->scan_check_range = 1;
    mm->prev_scanned_node = NULL;
}
EXPORT_SYMBOL(drm_mm_init_scan_with_range);

int drm_mm_scan_add_block(struct drm_mm_node *node)
{
    struct drm_mm *mm = node->mm;
    struct drm_mm_node *prev_node;
    unsigned long hole_start, hole_end;
    unsigned long adj_start;
    unsigned long adj_end;

    mm->scanned_blocks++;

    BUG_ON(node->scanned_block);
    node->scanned_block = 1;

    prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
                   node_list);

    node->scanned_preceeds_hole = prev_node->hole_follows;
    prev_node->hole_follows = 1;
    list_del(&node->node_list);
    node->node_list.prev = &prev_node->node_list;
    node->node_list.next = &mm->prev_scanned_node->node_list;
    mm->prev_scanned_node = node;

    hole_start = drm_mm_hole_node_start(prev_node);
    hole_end = drm_mm_hole_node_end(prev_node);

    adj_start = hole_start;
    adj_end = hole_end;

    if (mm->color_adjust)
        mm->color_adjust(prev_node, mm->scan_color, &adj_start, &adj_end);

    if (mm->scan_check_range) {
        if (adj_start < mm->scan_start)
            adj_start = mm->scan_start;
        if (adj_end > mm->scan_end)
            adj_end = mm->scan_end;
    }

    if (check_free_hole(adj_start, adj_end,
                mm->scan_size, mm->scan_alignment)) {
        mm->scan_hit_start = hole_start;
        mm->scan_hit_size = hole_end;

        return 1;
    }

    return 0;
}
EXPORT_SYMBOL(drm_mm_scan_add_block);

int drm_mm_scan_remove_block(struct drm_mm_node *node)
{
    struct drm_mm *mm = node->mm;
    struct drm_mm_node *prev_node;

    mm->scanned_blocks--;

    BUG_ON(!node->scanned_block);
    node->scanned_block = 0;

    prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
                   node_list);

    prev_node->hole_follows = node->scanned_preceeds_hole;
    INIT_LIST_HEAD(&node->node_list);
    list_add(&node->node_list, &prev_node->node_list);

    /* Only need to check for containement because start&size for the
     * complete resulting free block (not just the desired part) is
     * stored. */
    if (node->start >= mm->scan_hit_start &&
        node->start + node->size
                <= mm->scan_hit_start + mm->scan_hit_size) {
        return 1;
    }

    return 0;
}
EXPORT_SYMBOL(drm_mm_scan_remove_block);

int drm_mm_clean(struct drm_mm * mm)
{
    struct list_head *head = &mm->head_node.node_list;

    return (head->next->next == head);
}
EXPORT_SYMBOL(drm_mm_clean);

int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
{
    INIT_LIST_HEAD(&mm->hole_stack);
    INIT_LIST_HEAD(&mm->unused_nodes);
    mm->num_unused = 0;
    mm->scanned_blocks = 0;
    spin_lock_init(&mm->unused_lock);

    /* Clever trick to avoid a special case in the free hole tracking. */
    INIT_LIST_HEAD(&mm->head_node.node_list);
    INIT_LIST_HEAD(&mm->head_node.hole_stack);
    mm->head_node.hole_follows = 1;
    mm->head_node.scanned_block = 0;
    mm->head_node.scanned_prev_free = 0;
    mm->head_node.scanned_next_free = 0;
    mm->head_node.mm = mm;
    mm->head_node.start = start + size;
    mm->head_node.size = start - mm->head_node.start;
    list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);

    mm->color_adjust = NULL;

    return 0;
}
EXPORT_SYMBOL(drm_mm_init);

void drm_mm_takedown(struct drm_mm * mm)
{
    struct drm_mm_node *entry, *next;

    if (!list_empty(&mm->head_node.node_list)) {
        DRM_ERROR("Memory manager not clean. Delaying takedown\n");
        return;
    }

    spin_lock(&mm->unused_lock);
    list_for_each_entry_safe(entry, next, &mm->unused_nodes, node_list) {
        list_del(&entry->node_list);
        kfree(entry);
        --mm->num_unused;
    }
    spin_unlock(&mm->unused_lock);

    BUG_ON(mm->num_unused != 0);
}
EXPORT_SYMBOL(drm_mm_takedown);

void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
{
    struct drm_mm_node *entry;
    unsigned long total_used = 0, total_free = 0, total = 0;
    unsigned long hole_start, hole_end, hole_size;

    hole_start = drm_mm_hole_node_start(&mm->head_node);
    hole_end = drm_mm_hole_node_end(&mm->head_node);
    hole_size = hole_end - hole_start;
    if (hole_size)
        printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
            prefix, hole_start, hole_end,
            hole_size);
    total_free += hole_size;

    drm_mm_for_each_node(entry, mm) {
        printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",
            prefix, entry->start, entry->start + entry->size,
            entry->size);
        total_used += entry->size;

        if (entry->hole_follows) {
            hole_start = drm_mm_hole_node_start(entry);
            hole_end = drm_mm_hole_node_end(entry);
            hole_size = hole_end - hole_start;
            printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
                prefix, hole_start, hole_end,
                hole_size);
            total_free += hole_size;
        }
    }
    total = total_free + total_used;

    printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,
        total_used, total_free);
}
EXPORT_SYMBOL(drm_mm_debug_table);

#if defined(CONFIG_DEBUG_FS)
int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
{
    struct drm_mm_node *entry;
    unsigned long total_used = 0, total_free = 0, total = 0;
    unsigned long hole_start, hole_end, hole_size;

    hole_start = drm_mm_hole_node_start(&mm->head_node);
    hole_end = drm_mm_hole_node_end(&mm->head_node);
    hole_size = hole_end - hole_start;
    if (hole_size)
        seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
                hole_start, hole_end, hole_size);
    total_free += hole_size;

    drm_mm_for_each_node(entry, mm) {
        seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",
                entry->start, entry->start + entry->size,
                entry->size);
        total_used += entry->size;
        if (entry->hole_follows) {
            hole_start = drm_mm_hole_node_start(entry);
            hole_end = drm_mm_hole_node_end(entry);
            hole_size = hole_end - hole_start;
            seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
                    hole_start, hole_end, hole_size);
            total_free += hole_size;
        }
    }
    total = total_free + total_used;

    seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);
    return 0;
}
EXPORT_SYMBOL(drm_mm_dump_table);
#endif