static void zram_free_page(struct zram *zram, size_t index)
{
u32 clen;
void *obj;
struct page *page = zram->table[index].page;
u32 offset = zram->table[index].offset;
if (unlikely(!page)) {
/*
* No memory is allocated for zero filled pages.
* Simply clear zero page flag.
*/
if (zram_test_flag(zram, index, ZRAM_ZERO)) {
zram_clear_flag(zram, index, ZRAM_ZERO);
zram_stat_dec(&zram->stats.pages_zero);
}
return;
}
if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
clen = PAGE_SIZE;
__free_page(page);
zram_clear_flag(zram, index, ZRAM_UNCOMPRESSED);
zram_stat_dec(&zram->stats.pages_expand);
goto out;
}
obj = kmap_atomic(page, KM_USER0) + offset;
clen = xv_get_object_size(obj) - sizeof(struct zobj_header);
kunmap_atomic(obj, KM_USER0);
xv_free(zram->mem_pool, page, offset);
if (clen <= PAGE_SIZE / 2)
zram_stat_dec(&zram->stats.good_compress);
out:
zram_stat64_sub(zram, &zram->stats.compr_size, clen);
zram_stat_dec(&zram->stats.pages_stored);
zram->table[index].page = NULL;
zram->table[index].offset = 0;
}
static void zram_free_page(struct zram *zram, size_t index)
{
int zlen;
void *obj;
u32 offset;
struct page *page;
/*
* No memory is allocated for zero filled pages.
* Simply clear corresponding table entry.
*/
if (zram_is_zero_page(zram, index)) {
zram_clear_zero_page(zram, index);
zram_dec_stat(zram, ZRAM_STAT_PAGES_ZERO);
return;
}
zram_find_obj(zram, index, &page, &offset);
if (!page)
return;
/* Uncompressed pages cosume whole page, so offset is zero */
if (unlikely(!offset)) {
zlen = PAGE_SIZE;
__free_page(page);
zram_dec_stat(zram, ZRAM_STAT_PAGES_EXPAND);
goto out;
}
obj = kmap_atomic(page, KM_USER0) + offset;
zlen = xv_get_object_size(obj);
kunmap_atomic(obj, KM_USER0);
xv_free(zram->mem_pool, page, offset);
out:
zram_add_stat(zram, ZRAM_STAT_COMPR_SIZE, -zlen);
zram_dec_stat(zram, ZRAM_STAT_PAGES_STORED);
zram->table[index].addr = 0;
}