static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
int offset)
{
int ret = 0;
size_t clen;
unsigned long handle;
struct page *page;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
struct zram_meta *meta = zram->meta;
page = bvec->bv_page;
src = meta->compress_buffer;
if (is_partial_io(bvec)) {
/*
* This is a partial IO. We need to read the full page
* before to write the changes.
*/
uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
if (!uncmem) {
ret = -ENOMEM;
goto out;
}
ret = zram_decompress_page(zram, uncmem, index);
if (ret)
goto out;
}
/*
* System overwrites unused sectors. Free memory associated
* with this sector now.
*/
if (meta->table[index].handle ||
zram_test_flag(meta, index, ZRAM_ZERO))
zram_free_page(zram, index);
user_mem = kmap_atomic(page);
if (is_partial_io(bvec)) {
memcpy(uncmem + offset, user_mem + bvec->bv_offset,
bvec->bv_len);
kunmap_atomic(user_mem);
user_mem = NULL;
} else {
uncmem = user_mem;
}
if (page_zero_filled(uncmem)) {
kunmap_atomic(user_mem);
zram->stats.pages_zero++;
zram_set_flag(meta, index, ZRAM_ZERO);
ret = 0;
goto out;
}
ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
meta->compress_workmem);
if (!is_partial_io(bvec)) {
kunmap_atomic(user_mem);
user_mem = NULL;
uncmem = NULL;
}
if (unlikely(ret != LZO_E_OK)) {
pr_err("Compression failed! err=%d\n", ret);
goto out;
}
if (unlikely(clen > max_zpage_size)) {
zram->stats.bad_compress++;
clen = PAGE_SIZE;
src = NULL;
if (is_partial_io(bvec))
src = uncmem;
}
handle = zs_malloc(meta->mem_pool, clen);
if (!handle) {
pr_info("Error allocating memory for compressed "
"page: %u, size=%zu\n", index, clen);
ret = -ENOMEM;
goto out;
}
cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
src = kmap_atomic(page);
memcpy(cmem, src, clen);
if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
kunmap_atomic(src);
zs_unmap_object(meta->mem_pool, handle);
meta->table[index].handle = handle;
meta->table[index].size = clen;
/* Update stats */
zram_stat64_add(zram, &zram->stats.compr_size, clen);
zram->stats.pages_stored++;
if (clen <= PAGE_SIZE / 2)
zram->stats.good_compress++;
out:
if (is_partial_io(bvec))
kfree(uncmem);
if (ret)
zram_stat64_inc(zram, &zram->stats.failed_writes);
return ret;
}
static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
int offset)
{
int ret;
u32 store_offset;
size_t clen;
struct zobj_header *zheader;
struct page *page, *page_store;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
page = bvec->bv_page;
src = zram->compress_buffer;
if (is_partial_io(bvec)) {
/*
* This is a partial IO. We need to read the full page
* before to write the changes.
*/
uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!uncmem) {
pr_info("Error allocating temp memory!\n");
ret = -ENOMEM;
goto out;
}
ret = zram_read_before_write(zram, uncmem, index);
if (ret) {
kfree(uncmem);
goto out;
}
}
/*
* System overwrites unused sectors. Free memory associated
* with this sector now.
*/
if (zram->table[index].page ||
zram_test_flag(zram, index, ZRAM_ZERO))
zram_free_page(zram, index);
user_mem = kmap_atomic(page, KM_USER0);
if (is_partial_io(bvec))
memcpy(uncmem + offset, user_mem + bvec->bv_offset,
bvec->bv_len);
else
uncmem = user_mem;
if (page_zero_filled(uncmem)) {
kunmap_atomic(user_mem, KM_USER0);
if (is_partial_io(bvec))
kfree(uncmem);
zram_stat_inc(&zram->stats.pages_zero);
zram_set_flag(zram, index, ZRAM_ZERO);
ret = 0;
goto out;
}
COMPRESS(uncmem, PAGE_SIZE, src, &clen,
zram->compress_workmem);
ret = 0;
kunmap_atomic(user_mem, KM_USER0);
if (is_partial_io(bvec))
kfree(uncmem);
if (unlikely(ret != 0)) {
pr_err("Compression failed! err=%d\n", ret);
goto out;
}
/*
* Page is incompressible. Store it as-is (uncompressed)
* since we do not want to return too many disk write
* errors which has side effect of hanging the system.
*/
if (unlikely(clen > max_zpage_size)) {
clen = PAGE_SIZE;
page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
if (unlikely(!page_store)) {
pr_info("Error allocating memory for "
"incompressible page: %u\n", index);
ret = -ENOMEM;
goto out;
}
store_offset = 0;
zram_set_flag(zram, index, ZRAM_UNCOMPRESSED);
zram_stat_inc(&zram->stats.pages_expand);
zram->table[index].page = page_store;
src = kmap_atomic(page, KM_USER0);
goto memstore;
}
if (xv_malloc(zram->mem_pool, clen + sizeof(*zheader),
&zram->table[index].page, &store_offset,
GFP_NOIO | __GFP_HIGHMEM)) {
pr_info("Error allocating memory for compressed "
"page: %u, size=%zu\n", index, clen);
ret = -ENOMEM;
goto out;
}
memstore:
zram->table[index].offset = store_offset;
cmem = kmap_atomic(zram->table[index].page, KM_USER1) +
zram->table[index].offset;
#if 0
/* Back-reference needed for memory defragmentation */
if (!zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)) {
zheader = (struct zobj_header *)cmem;
zheader->table_idx = index;
cmem += sizeof(*zheader);
}
#endif
memcpy(cmem, src, clen);
kunmap_atomic(cmem, KM_USER1);
if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)))
kunmap_atomic(src, KM_USER0);
/* Update stats */
zram_stat64_add(zram, &zram->stats.compr_size, clen);
zram_stat_inc(&zram->stats.pages_stored);
if (clen <= PAGE_SIZE / 2)
zram_stat_inc(&zram->stats.good_compress);
return 0;
out:
if (ret)
zram_stat64_inc(zram, &zram->stats.failed_writes);
return ret;
}
/* attempts to compress and store an single page */
static int zswap_frontswap_store(unsigned type, pgoff_t offset,
struct page *page)
{
struct zswap_tree *tree = zswap_trees[type];
struct zswap_entry *entry, *dupentry;
int ret;
unsigned int dlen = PAGE_SIZE, len;
unsigned long handle;
char *buf;
u8 *src, *dst;
struct zswap_header *zhdr;
if (!tree) {
ret = -ENODEV;
goto reject;
}
/* if this page got EIO on pageout before, give up immediately */
if (PageError(page)) {
ret = -ENOMEM;
goto reject;
}
/* reclaim space if needed */
if (zswap_is_full()) {
zswap_pool_limit_hit++;
if (zpool_shrink(zswap_pool, 1, NULL)) {
zswap_reject_reclaim_fail++;
ret = -ENOMEM;
goto reject;
}
}
/* allocate entry */
entry = zswap_entry_cache_alloc(GFP_KERNEL);
if (!entry) {
zswap_reject_kmemcache_fail++;
ret = -ENOMEM;
goto reject;
}
/* compress */
src = kmap_atomic(page);
if (page_zero_filled(src)) {
atomic_inc(&zswap_zero_pages);
entry->zero_flag = 1;
kunmap_atomic(src);
handle = 0;
dlen = PAGE_SIZE;
goto zeropage_out;
}
dst = get_cpu_var(zswap_dstmem);
ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
kunmap_atomic(src);
if (ret) {
ret = -EINVAL;
goto freepage;
}
/* store */
len = dlen + sizeof(struct zswap_header);
ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
&handle);
if (ret == -ENOSPC) {
zswap_reject_compress_poor++;
goto freepage;
}
if (ret) {
zswap_reject_alloc_fail++;
goto freepage;
}
zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
zhdr->swpentry = swp_entry(type, offset);
buf = (u8 *)(zhdr + 1);
memcpy(buf, dst, dlen);
zpool_unmap_handle(zswap_pool, handle);
put_cpu_var(zswap_dstmem);
zeropage_out:
/* populate entry */
entry->offset = offset;
entry->handle = handle;
entry->length = dlen;
/* map */
spin_lock(&tree->lock);
do {
ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry);
if (ret == -EEXIST) {
zswap_duplicate_entry++;
/* remove from rbtree */
zswap_rb_erase(&tree->rbroot, dupentry);
zswap_entry_put(tree, dupentry);
}
} while (ret == -EEXIST);
spin_unlock(&tree->lock);
/* update stats */
atomic_inc(&zswap_stored_pages);
zswap_pool_total_size = zpool_get_total_size(zswap_pool);
zswap_pool_pages = zswap_pool_total_size >> PAGE_SHIFT;
return 0;
freepage:
put_cpu_var(zswap_dstmem);
zswap_entry_cache_free(entry);
reject:
return ret;
}
