/*
* Remove block from freelist. Index 'slindex' identifies the freelist.
*/
static void remove_block(struct xv_pool *pool, struct page *page, u32 offset,
struct block_header *block, u32 slindex)
{
u32 flindex;
struct block_header *tmpblock;
if (pool->freelist[slindex].page == page
&& pool->freelist[slindex].offset == offset) {
remove_block_head(pool, block, slindex);
return;
}
flindex = slindex / BITS_PER_LONG;
if (block->link.prev_page) {
tmpblock = get_ptr_atomic(block->link.prev_page,
block->link.prev_offset, KM_USER1);
tmpblock->link.next_page = block->link.next_page;
tmpblock->link.next_offset = block->link.next_offset;
put_ptr_atomic(tmpblock, KM_USER1);
}
if (block->link.next_page) {
tmpblock = get_ptr_atomic(block->link.next_page,
block->link.next_offset, KM_USER1);
tmpblock->link.prev_page = block->link.prev_page;
tmpblock->link.prev_offset = block->link.prev_offset;
put_ptr_atomic(tmpblock, KM_USER1);
}
}
/*
* Remove block from freelist. Index 'slindex' identifies the freelist.
*/
static void remove_block(struct xv_pool *pool, struct page *page, u32 offset,
struct block_header *block, u32 slindex)
{
u32 flindex = slindex / BITS_PER_LONG;
struct block_header *tmpblock;
if (block->link.prev_page) {
tmpblock = get_ptr_atomic(block->link.prev_page,
block->link.prev_offset, KM_USER1);
tmpblock->link.next_page = block->link.next_page;
tmpblock->link.next_offset = block->link.next_offset;
put_ptr_atomic(tmpblock, KM_USER1);
}
if (block->link.next_page) {
tmpblock = get_ptr_atomic(block->link.next_page,
block->link.next_offset, KM_USER1);
tmpblock->link.prev_page = block->link.prev_page;
tmpblock->link.prev_offset = block->link.prev_offset;
put_ptr_atomic(tmpblock, KM_USER1);
}
/* Is this block is at the head of the freelist? */
if (pool->freelist[slindex].page == page
&& pool->freelist[slindex].offset == offset) {
pool->freelist[slindex].page = block->link.next_page;
pool->freelist[slindex].offset = block->link.next_offset;
if (pool->freelist[slindex].page) {
struct block_header *tmpblock;
tmpblock = get_ptr_atomic(pool->freelist[slindex].page,
pool->freelist[slindex].offset,
KM_USER1);
tmpblock->link.prev_page = NULL;
tmpblock->link.prev_offset = 0;
put_ptr_atomic(tmpblock, KM_USER1);
} else {
/* This freelist bucket is empty */
__clear_bit(slindex % BITS_PER_LONG,
&pool->slbitmap[flindex]);
if (!pool->slbitmap[flindex])
__clear_bit(flindex, &pool->flbitmap);
}
}
block->link.prev_page = NULL;
block->link.prev_offset = 0;
block->link.next_page = NULL;
block->link.next_offset = 0;
}
/*
* Allocate a page and add it to freelist of given pool.
*/
static int grow_pool(struct xv_pool *pool, gfp_t flags)
{
struct page *page;
struct block_header *block;
page = alloc_page(flags);
if (unlikely(!page))
return -ENOMEM;
stat_inc(&pool->total_pages);
spin_lock(&pool->lock);
block = get_ptr_atomic(page, 0);
block->size = PAGE_SIZE - XV_ALIGN;
set_flag(block, BLOCK_FREE);
clear_flag(block, PREV_FREE);
set_blockprev(block, 0);
insert_block(pool, page, 0, block);
put_ptr_atomic(block);
spin_unlock(&pool->lock);
return 0;
}
/*
* Insert block at <page, offset> in freelist of given pool.
* freelist used depends on block size.
*/
static void insert_block(struct xv_pool *pool, struct page *page, u32 offset,
struct block_header *block)
{
u32 flindex, slindex;
struct block_header *nextblock;
slindex = get_index_for_insert(block->size);
flindex = slindex / BITS_PER_LONG;
block->link.prev_page = NULL;
block->link.prev_offset = 0;
block->link.next_page = pool->freelist[slindex].page;
block->link.next_offset = pool->freelist[slindex].offset;
pool->freelist[slindex].page = page;
pool->freelist[slindex].offset = offset;
if (block->link.next_page) {
nextblock = get_ptr_atomic(block->link.next_page,
block->link.next_offset);
nextblock->link.prev_page = page;
nextblock->link.prev_offset = offset;
put_ptr_atomic(nextblock);
/* If there was a next page then the free bits are set. */
return;
}
__set_bit(slindex % BITS_PER_LONG, &pool->slbitmap[flindex]);
__set_bit(flindex, &pool->flbitmap);
}
/*
* Remove block from head of freelist. Index 'slindex' identifies the freelist.
*/
static void remove_block_head(struct xv_pool *pool,
struct block_header *block, u32 slindex)
{
struct block_header *tmpblock;
u32 flindex = slindex / BITS_PER_LONG;
pool->freelist[slindex].page = block->link.next_page;
pool->freelist[slindex].offset = block->link.next_offset;
block->link.prev_page = 0;
block->link.prev_offset = 0;
if (!pool->freelist[slindex].page) {
__clear_bit(slindex % BITS_PER_LONG, &pool->slbitmap[flindex]);
if (!pool->slbitmap[flindex])
__clear_bit(flindex, &pool->flbitmap);
} else {
/*
* DEBUG ONLY: We need not reinitialize freelist head previous
* pointer to 0 - we never depend on its value. But just for
* sanity, lets do it.
*/
tmpblock = get_ptr_atomic(pool->freelist[slindex].page,
pool->freelist[slindex].offset, KM_USER1);
tmpblock->link.prev_page = 0;
tmpblock->link.prev_offset = 0;
put_ptr_atomic(tmpblock, KM_USER1);
}
}
/*
* Insert block at <pagenum, offset> in freelist of given pool.
* freelist used depends on block size.
*/
static void insert_block(struct xv_pool *pool, u32 pagenum, u32 offset,
struct block_header *block)
{
u32 flindex, slindex;
struct block_header *nextblock;
slindex = get_index_for_insert(block->size);
flindex = slindex / BITS_PER_LONG;
block->link.prev_pagenum = 0;
block->link.prev_offset = 0;
block->link.next_pagenum = pool->freelist[slindex].pagenum;
block->link.next_offset = pool->freelist[slindex].offset;
pool->freelist[slindex].pagenum = pagenum;
pool->freelist[slindex].offset = offset;
if (block->link.next_pagenum) {
nextblock = get_ptr_atomic(block->link.next_pagenum,
block->link.next_offset, KM_USER1);
nextblock->link.prev_pagenum = pagenum;
nextblock->link.prev_offset = offset;
put_ptr_atomic(nextblock, KM_USER1);
}
__set_bit(slindex % BITS_PER_LONG, &pool->slbitmap[flindex]);
__set_bit(flindex, &pool->flbitmap);
}
/*
* Free block identified with <page, offset>
*/
void xv_free(struct xv_pool *pool, struct page *page, u32 offset)
{
void *page_start;
struct block_header *block, *tmpblock;
offset -= XV_ALIGN;
spin_lock(&pool->lock);
page_start = get_ptr_atomic(page, 0);
block = (struct block_header *)((char *)page_start + offset);
/* Catch double free bugs */
BUG_ON(test_flag(block, BLOCK_FREE));
block->size = ALIGN(block->size, XV_ALIGN);
tmpblock = BLOCK_NEXT(block);
if (offset + block->size + XV_ALIGN == PAGE_SIZE)
tmpblock = NULL;
/* Merge next block if its free */
if (tmpblock && test_flag(tmpblock, BLOCK_FREE)) {
/*
* Blocks smaller than XV_MIN_ALLOC_SIZE
* are not inserted in any free list.
*/
if (tmpblock->size >= XV_MIN_ALLOC_SIZE) {
remove_block(pool, page,
offset + block->size + XV_ALIGN, tmpblock,
get_index_for_insert(tmpblock->size));
}
block->size += tmpblock->size + XV_ALIGN;
}
/* Merge previous block if its free */
if (test_flag(block, PREV_FREE)) {
tmpblock = (struct block_header *)((char *)(page_start) +
get_blockprev(block));
offset = offset - tmpblock->size - XV_ALIGN;
if (tmpblock->size >= XV_MIN_ALLOC_SIZE)
remove_block(pool, page, offset, tmpblock,
get_index_for_insert(tmpblock->size));
tmpblock->size += block->size + XV_ALIGN;
block = tmpblock;
}
/* No used objects in this page. Free it. */
if (block->size == PAGE_SIZE - XV_ALIGN) {
put_ptr_atomic(page_start);
spin_unlock(&pool->lock);
__free_page(page);
stat_dec(&pool->total_pages);
return;
}
set_flag(block, BLOCK_FREE);
if (block->size >= XV_MIN_ALLOC_SIZE)
insert_block(pool, page, offset, block);
if (offset + block->size + XV_ALIGN != PAGE_SIZE) {
tmpblock = BLOCK_NEXT(block);
set_flag(tmpblock, PREV_FREE);
set_blockprev(tmpblock, offset);
}
put_ptr_atomic(page_start);
spin_unlock(&pool->lock);
}
/**
* xv_malloc - Allocate block of given size from pool.
* @pool: pool to allocate from
* @size: size of block to allocate
* @page: page no. that holds the object
* @offset: location of object within page
*
* On success, <page, offset> identifies block allocated
* and 0 is returned. On failure, <page, offset> is set to
* 0 and -ENOMEM is returned.
*
* Allocation requests with size > XV_MAX_ALLOC_SIZE will fail.
*/
int xv_malloc(struct xv_pool *pool, u32 size, struct page **page,
u32 *offset, gfp_t flags)
{
int error;
u32 index, tmpsize, origsize, tmpoffset;
struct block_header *block, *tmpblock;
*page = NULL;
*offset = 0;
origsize = size;
if (unlikely(!size || size > XV_MAX_ALLOC_SIZE))
return -ENOMEM;
size = ALIGN(size, XV_ALIGN);
spin_lock(&pool->lock);
index = find_block(pool, size, page, offset);
if (!*page) {
spin_unlock(&pool->lock);
if (flags & GFP_NOWAIT)
return -ENOMEM;
error = grow_pool(pool, flags);
if (unlikely(error))
return error;
spin_lock(&pool->lock);
index = find_block(pool, size, page, offset);
}
if (!*page) {
spin_unlock(&pool->lock);
return -ENOMEM;
}
block = get_ptr_atomic(*page, *offset);
remove_block(pool, *page, *offset, block, index);
/* Split the block if required */
tmpoffset = *offset + size + XV_ALIGN;
tmpsize = block->size - size;
tmpblock = (struct block_header *)((char *)block + size + XV_ALIGN);
if (tmpsize) {
tmpblock->size = tmpsize - XV_ALIGN;
set_flag(tmpblock, BLOCK_FREE);
clear_flag(tmpblock, PREV_FREE);
set_blockprev(tmpblock, *offset);
if (tmpblock->size >= XV_MIN_ALLOC_SIZE)
insert_block(pool, *page, tmpoffset, tmpblock);
if (tmpoffset + XV_ALIGN + tmpblock->size != PAGE_SIZE) {
tmpblock = BLOCK_NEXT(tmpblock);
set_blockprev(tmpblock, tmpoffset);
}
} else {
/* This block is exact fit */
if (tmpoffset != PAGE_SIZE)
clear_flag(tmpblock, PREV_FREE);
}
block->size = origsize;
clear_flag(block, BLOCK_FREE);
put_ptr_atomic(block);
spin_unlock(&pool->lock);
*offset += XV_ALIGN;
return 0;
}
