rheap.c

linux 内核源代码

	/* Validate size */
	if (size <= 0)
		return (unsigned long) -EINVAL;

	/* The region must be aligned */
	s = start;
	e = s + size;
	m = info->alignment - 1;

	/* Round start up */
	s = (s + m) & ~m;

	/* Round end down */
	e = e & ~m;

	if (assure_empty(info, 1) < 0)
		return (unsigned long) -ENOMEM;

	blk = NULL;
	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);
		/* The range must lie entirely inside one free block */
		bs = blk->start;
		be = blk->start + blk->size;
		if (s >= bs && e <= be)
			break;
		blk = NULL;
	}

	if (blk == NULL)
		return (unsigned long) -ENOMEM;

	/* Perfect fit */
	if (bs == s && be == e) {
		/* Delete from free list, release slot */
		list_del(&blk->list);
		release_slot(info, blk);
		return s;
	}

	/* blk still in free list, with updated start and/or size */
	if (bs == s || be == e) {
		if (bs == s)
			blk->start += size;
		blk->size -= size;

	} else {
		/* The front free fragment */
		blk->size = s - bs;

		/* the back free fragment */
		newblk = get_slot(info);
		newblk->start = e;
		newblk->size = be - e;

		list_add(&newblk->list, &blk->list);
	}

	return s;
}
EXPORT_SYMBOL_GPL(rh_detach_region);

/* Allocate a block of memory at the specified alignment.  The value returned
 * is an offset into the buffer initialized by rh_init(), or a negative number
 * if there is an error.
 */
unsigned long rh_alloc_align(rh_info_t * info, int size, int alignment, const char *owner)
{
	struct list_head *l;
	rh_block_t *blk;
	rh_block_t *newblk;
	unsigned long start, sp_size;

	/* Validate size, and alignment must be power of two */
	if (size <= 0 || (alignment & (alignment - 1)) != 0)
		return (unsigned long) -EINVAL;

	/* Align to configured alignment */
	size = (size + (info->alignment - 1)) & ~(info->alignment - 1);

	if (assure_empty(info, 2) < 0)
		return (unsigned long) -ENOMEM;

	blk = NULL;
	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);
		if (size <= blk->size) {
			start = (blk->start + alignment - 1) & ~(alignment - 1);
			if (start + size <= blk->start + blk->size)
				break;
		}
		blk = NULL;
	}

	if (blk == NULL)
		return (unsigned long) -ENOMEM;

	/* Just fits */
	if (blk->size == size) {
		/* Move from free list to taken list */
		list_del(&blk->list);
		newblk = blk;
	} else {
		/* Fragment caused, split if needed */
		/* Create block for fragment in the beginning */
		sp_size = start - blk->start;
		if (sp_size) {
			rh_block_t *spblk;

			spblk = get_slot(info);
			spblk->start = blk->start;
			spblk->size = sp_size;
			/* add before the blk */
			list_add(&spblk->list, blk->list.prev);
		}
		newblk = get_slot(info);
		newblk->start = start;
		newblk->size = size;

		/* blk still in free list, with updated start and size
		 * for fragment in the end */
		blk->start = start + size;
		blk->size -= sp_size + size;
		/* No fragment in the end, remove blk */
		if (blk->size == 0) {
			list_del(&blk->list);
			release_slot(info, blk);
		}
	}

	newblk->owner = owner;
	attach_taken_block(info, newblk);

	return start;
}
EXPORT_SYMBOL_GPL(rh_alloc_align);

/* Allocate a block of memory at the default alignment.  The value returned is
 * an offset into the buffer initialized by rh_init(), or a negative number if
 * there is an error.
 */
unsigned long rh_alloc(rh_info_t * info, int size, const char *owner)
{
	return rh_alloc_align(info, size, info->alignment, owner);
}
EXPORT_SYMBOL_GPL(rh_alloc);

/* Allocate a block of memory at the given offset, rounded up to the default
 * alignment.  The value returned is an offset into the buffer initialized by
 * rh_init(), or a negative number if there is an error.
 */
unsigned long rh_alloc_fixed(rh_info_t * info, unsigned long start, int size, const char *owner)
{
	struct list_head *l;
	rh_block_t *blk, *newblk1, *newblk2;
	unsigned long s, e, m, bs = 0, be = 0;

	/* Validate size */
	if (size <= 0)
		return (unsigned long) -EINVAL;

	/* The region must be aligned */
	s = start;
	e = s + size;
	m = info->alignment - 1;

	/* Round start up */
	s = (s + m) & ~m;

	/* Round end down */
	e = e & ~m;

	if (assure_empty(info, 2) < 0)
		return (unsigned long) -ENOMEM;

	blk = NULL;
	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);
		/* The range must lie entirely inside one free block */
		bs = blk->start;
		be = blk->start + blk->size;
		if (s >= bs && e <= be)
			break;
	}

	if (blk == NULL)
		return (unsigned long) -ENOMEM;

	/* Perfect fit */
	if (bs == s && be == e) {
		/* Move from free list to taken list */
		list_del(&blk->list);
		blk->owner = owner;

		start = blk->start;
		attach_taken_block(info, blk);

		return start;

	}

	/* blk still in free list, with updated start and/or size */
	if (bs == s || be == e) {
		if (bs == s)
			blk->start += size;
		blk->size -= size;

	} else {
		/* The front free fragment */
		blk->size = s - bs;

		/* The back free fragment */
		newblk2 = get_slot(info);
		newblk2->start = e;
		newblk2->size = be - e;

		list_add(&newblk2->list, &blk->list);
	}

	newblk1 = get_slot(info);
	newblk1->start = s;
	newblk1->size = e - s;
	newblk1->owner = owner;

	start = newblk1->start;
	attach_taken_block(info, newblk1);

	return start;
}
EXPORT_SYMBOL_GPL(rh_alloc_fixed);

/* Deallocate the memory previously allocated by one of the rh_alloc functions.
 * The return value is the size of the deallocated block, or a negative number
 * if there is an error.
 */
int rh_free(rh_info_t * info, unsigned long start)
{
	rh_block_t *blk, *blk2;
	struct list_head *l;
	int size;

	/* Linear search for block */
	blk = NULL;
	list_for_each(l, &info->taken_list) {
		blk2 = list_entry(l, rh_block_t, list);
		if (start < blk2->start)
			break;
		blk = blk2;
	}

	if (blk == NULL || start > (blk->start + blk->size))
		return -EINVAL;

	/* Remove from taken list */
	list_del(&blk->list);

	/* Get size of freed block */
	size = blk->size;
	attach_free_block(info, blk);

	return size;
}
EXPORT_SYMBOL_GPL(rh_free);

int rh_get_stats(rh_info_t * info, int what, int max_stats, rh_stats_t * stats)
{
	rh_block_t *blk;
	struct list_head *l;
	struct list_head *h;
	int nr;

	switch (what) {

	case RHGS_FREE:
		h = &info->free_list;
		break;

	case RHGS_TAKEN:
		h = &info->taken_list;
		break;

	default:
		return -EINVAL;
	}

	/* Linear search for block */
	nr = 0;
	list_for_each(l, h) {
		blk = list_entry(l, rh_block_t, list);
		if (stats != NULL && nr < max_stats) {
			stats->start = blk->start;
			stats->size = blk->size;
			stats->owner = blk->owner;
			stats++;
		}
		nr++;
	}

	return nr;
}
EXPORT_SYMBOL_GPL(rh_get_stats);

int rh_set_owner(rh_info_t * info, unsigned long start, const char *owner)
{
	rh_block_t *blk, *blk2;
	struct list_head *l;
	int size;

	/* Linear search for block */
	blk = NULL;
	list_for_each(l, &info->taken_list) {
		blk2 = list_entry(l, rh_block_t, list);
		if (start < blk2->start)
			break;
		blk = blk2;
	}

	if (blk == NULL || start > (blk->start + blk->size))
		return -EINVAL;

	blk->owner = owner;
	size = blk->size;

	return size;
}
EXPORT_SYMBOL_GPL(rh_set_owner);

void rh_dump(rh_info_t * info)
{
	static rh_stats_t st[32];	/* XXX maximum 32 blocks */
	int maxnr;
	int i, nr;

	maxnr = ARRAY_SIZE(st);

	printk(KERN_INFO
	       "info @0x%p (%d slots empty / %d max)\n",
	       info, info->empty_slots, info->max_blocks);

	printk(KERN_INFO "  Free:\n");
	nr = rh_get_stats(info, RHGS_FREE, maxnr, st);
	if (nr > maxnr)
		nr = maxnr;
	for (i = 0; i < nr; i++)
		printk(KERN_INFO
		       "    0x%lx-0x%lx (%u)\n",
		       st[i].start, st[i].start + st[i].size,
		       st[i].size);
	printk(KERN_INFO "\n");

	printk(KERN_INFO "  Taken:\n");
	nr = rh_get_stats(info, RHGS_TAKEN, maxnr, st);
	if (nr > maxnr)
		nr = maxnr;
	for (i = 0; i < nr; i++)
		printk(KERN_INFO
		       "    0x%lx-0x%lx (%u) %s\n",
		       st[i].start, st[i].start + st[i].size,
		       st[i].size, st[i].owner != NULL ? st[i].owner : "");
	printk(KERN_INFO "\n");
}
EXPORT_SYMBOL_GPL(rh_dump);

void rh_dump_blk(rh_info_t * info, rh_block_t * blk)
{
	printk(KERN_INFO
	       "blk @0x%p: 0x%lx-0x%lx (%u)\n",
	       blk, blk->start, blk->start + blk->size, blk->size);
}
EXPORT_SYMBOL_GPL(rh_dump_blk);