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kernel_samsung_a34x-permissive/drivers/block/zram/zram_drv.c

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Import A346BXXU1AWB9 kernel source Android 13
2024-04-28 06:49:01 -07:00
/*
* Compressed RAM block device
*
* Copyright (C) 2008, 2009, 2010 Nitin Gupta
* 2012, 2013 Minchan Kim
*
* This code is released using a dual license strategy: BSD/GPL
* You can choose the licence that better fits your requirements.
*
* Released under the terms of 3-clause BSD License
* Released under the terms of GNU General Public License Version 2.0
*
*/
#define KMSG_COMPONENT "zram"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bio.h>
#include <linux/bitops.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/device.h>
#include <linux/genhd.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/backing-dev.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/sysfs.h>
#include <linux/debugfs.h>
#include <linux/cpuhotplug.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/jiffies.h>
#include <linux/vmstat.h>
#include <linux/statfs.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/swapfile.h>
#include <linux/delay.h>
#include <linux/compat.h>
#include <uapi/linux/falloc.h>
#include <uapi/linux/sched/types.h>
#include "zram_drv.h"
#include "../loop.h"
#define NON_LRU_SWAPPINESS 99
/* Total bytes used by the compressed storage */
static u64 zram_pool_total_size;
static DEFINE_IDR(zram_index_idr);
/* idr index must be protected */
static DEFINE_MUTEX(zram_index_mutex);
static int zram_major;
#if IS_ENABLED(CONFIG_CRYPTO_LZ4)
static const char *default_compressor = "lz4";
#else
static const char *default_compressor = "lzo";
#endif
/* Module params (documentation at end) */
static unsigned int num_devices = 1;
/*
* Pages that compress to sizes equals or greater than this are stored
* uncompressed in memory.
*/
static size_t huge_class_size;
static void zram_free_page(struct zram *zram, size_t index);
static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
u32 index, int offset, struct bio *bio);
static int zram_slot_trylock(struct zram *zram, u32 index)
{
return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].flags);
}
static void zram_slot_lock(struct zram *zram, u32 index)
{
bit_spin_lock(ZRAM_LOCK, &zram->table[index].flags);
}
static void zram_slot_unlock(struct zram *zram, u32 index)
{
bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
}
static inline bool init_done(struct zram *zram)
{
return zram->disksize;
}
static inline struct zram *dev_to_zram(struct device *dev)
{
return (struct zram *)dev_to_disk(dev)->private_data;
}
static unsigned long zram_get_handle(struct zram *zram, u32 index)
{
return zram->table[index].handle;
}
static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle)
{
zram->table[index].handle = handle;
}
/* flag operations require table entry bit_spin_lock() being held */
static bool zram_test_flag(struct zram *zram, u32 index,
enum zram_pageflags flag)
{
return zram->table[index].flags & BIT(flag);
}
static void zram_set_flag(struct zram *zram, u32 index,
enum zram_pageflags flag)
{
zram->table[index].flags |= BIT(flag);
}
static void zram_clear_flag(struct zram *zram, u32 index,
enum zram_pageflags flag)
{
zram->table[index].flags &= ~BIT(flag);
}
static inline void zram_set_element(struct zram *zram, u32 index,
unsigned long element)
{
zram->table[index].element = element;
}
static unsigned long zram_get_element(struct zram *zram, u32 index)
{
return zram->table[index].element;
}
static size_t zram_get_obj_size(struct zram *zram, u32 index)
{
return zram->table[index].flags & (BIT(ZRAM_FLAG_SHIFT) - 1);
}
static void zram_set_obj_size(struct zram *zram,
u32 index, size_t size)
{
unsigned long flags = zram->table[index].flags >> ZRAM_FLAG_SHIFT;
zram->table[index].flags = (flags << ZRAM_FLAG_SHIFT) | size;
}
static inline bool zram_allocated(struct zram *zram, u32 index)
{
return zram_get_obj_size(zram, index) ||
zram_test_flag(zram, index, ZRAM_SAME) ||
zram_test_flag(zram, index, ZRAM_WB);
}
#if PAGE_SIZE != 4096
static inline bool is_partial_io(struct bio_vec *bvec)
{
return bvec->bv_len != PAGE_SIZE;
}
#else
static inline bool is_partial_io(struct bio_vec *bvec)
{
return false;
}
#endif
/*
* Check if request is within bounds and aligned on zram logical blocks.
*/
static inline bool valid_io_request(struct zram *zram,
sector_t start, unsigned int size)
{
u64 end, bound;
/* unaligned request */
if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
return false;
if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
return false;
end = start + (size >> SECTOR_SHIFT);
bound = zram->disksize >> SECTOR_SHIFT;
/* out of range range */
if (unlikely(start >= bound || end > bound || start > end))
return false;
/* I/O request is valid */
return true;
}
static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
{
*index += (*offset + bvec->bv_len) / PAGE_SIZE;
*offset = (*offset + bvec->bv_len) % PAGE_SIZE;
}
static inline void update_used_max(struct zram *zram,
const unsigned long pages)
{
unsigned long old_max, cur_max;
old_max = atomic_long_read(&zram->stats.max_used_pages);
do {
cur_max = old_max;
if (pages > cur_max)
old_max = atomic_long_cmpxchg(
&zram->stats.max_used_pages, cur_max, pages);
} while (old_max != cur_max);
}
static inline void zram_fill_page(void *ptr, unsigned long len,
unsigned long value)
{
WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long)));
memset_l(ptr, value, len / sizeof(unsigned long));
}
static bool page_same_filled(void *ptr, unsigned long *element)
{
unsigned int pos;
unsigned long *page;
unsigned long val;
page = (unsigned long *)ptr;
val = page[0];
for (pos = 1; pos < PAGE_SIZE / sizeof(*page); pos++) {
if (val != page[pos])
return false;
}
*element = val;
return true;
}
static ssize_t initstate_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
u32 val;
struct zram *zram = dev_to_zram(dev);
down_read(&zram->init_lock);
val = init_done(zram);
up_read(&zram->init_lock);
return scnprintf(buf, PAGE_SIZE, "%u\n", val);
}
static ssize_t disksize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
}
static ssize_t mem_limit_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
u64 limit;
char *tmp;
struct zram *zram = dev_to_zram(dev);
limit = memparse(buf, &tmp);
if (buf == tmp) /* no chars parsed, invalid input */
return -EINVAL;
down_write(&zram->init_lock);
zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
up_write(&zram->init_lock);
return len;
}
static ssize_t mem_used_max_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int err;
unsigned long val;
struct zram *zram = dev_to_zram(dev);
err = kstrtoul(buf, 10, &val);
if (err || val != 0)
return -EINVAL;
down_read(&zram->init_lock);
if (init_done(zram)) {
atomic_long_set(&zram->stats.max_used_pages,
zs_get_total_pages(zram->mem_pool));
}
up_read(&zram->init_lock);
return len;
}
static ssize_t idle_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
int index;
char mode_buf[8];
ssize_t sz;
sz = strscpy(mode_buf, buf, sizeof(mode_buf));
if (sz <= 0)
return -EINVAL;
/* ignore trailing new line */
if (mode_buf[sz - 1] == '\n')
mode_buf[sz - 1] = 0x00;
if (strcmp(mode_buf, "all"))
return -EINVAL;
down_read(&zram->init_lock);
if (!init_done(zram)) {
up_read(&zram->init_lock);
return -EINVAL;
}
for (index = 0; index < nr_pages; index++) {
/*
* Do not mark ZRAM_UNDER_WB slot as ZRAM_IDLE to close race.
* See the comment in writeback_store.
*/
zram_slot_lock(zram, index);
if (zram_allocated(zram, index) &&
!zram_test_flag(zram, index, ZRAM_UNDER_WB))
zram_set_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
}
up_read(&zram->init_lock);
return len;
}
#ifdef CONFIG_ZRAM_WRITEBACK
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
static int zram_wbd(void *p);
static struct zram *g_zram;
static bool is_app_launch;
#define F2FS_IOCTL_MAGIC 0xf5
#define F2FS_IOC_SET_PIN_FILE _IOW(F2FS_IOCTL_MAGIC, 13, __u32)
#define F2FS_SET_PIN_FILE 1
static int zram_pin_backing_file(struct zram *zram)
{
struct loop_device *lo = zram->bdev->bd_disk->private_data;
struct file *file = lo->lo_backing_file;
unsigned int cmd = F2FS_IOC_SET_PIN_FILE;
int __user *buf;
int set = F2FS_SET_PIN_FILE;
int ret;
buf = compat_alloc_user_space(sizeof(*buf));
if (!buf) {
pr_info("%s failed to compat_alloc_user_space\n", __func__);
return -ENOMEM;
}
copy_to_user(buf, &set, sizeof(int));
ret = file->f_op->unlocked_ioctl(file, cmd, (unsigned long)buf);
pr_info("%s ioctl to pin file returned %d\n", __func__, ret);
return ret;
}
static void fallocate_block(struct zram *zram, unsigned long blk_idx)
{
struct block_device *bdev = zram->bdev;
if (!bdev)
return;
mutex_lock(&zram->blk_bitmap_lock);
/* check 2MB block bitmap. if unset, fallocate 2MB block at once */
if (!test_and_set_bit(blk_idx / NR_FALLOC_PAGES, zram->blk_bitmap)) {
struct loop_device *lo = bdev->bd_disk->private_data;
struct file *file = lo->lo_backing_file;
loff_t pos = (blk_idx & FALLOC_ALIGN_MASK) << PAGE_SHIFT;
loff_t len = NR_FALLOC_PAGES << PAGE_SHIFT;
int mode = FALLOC_FL_KEEP_SIZE;
int ret;
file_start_write(file);
ret = file->f_op->fallocate(file, mode, pos, len);
if (ret)
pr_err("%s pos %lx failed %d\n", __func__, pos, ret);
file_end_write(file);
}
mutex_unlock(&zram->blk_bitmap_lock);
}
static int init_lru_writeback(struct zram *zram)
{
struct sched_param param = { .sched_priority = 0 };
int ret = 0;
int bitmap_sz;
init_waitqueue_head(&zram->wbd_wait);
zram->wb_table = kvzalloc(sizeof(u8) * zram->nr_pages, GFP_KERNEL);
if (!zram->wb_table) {
ret = -ENOMEM;
return ret;
}
/* bitmap for 2MB block */
bitmap_sz = (BITS_TO_LONGS(zram->nr_pages) * sizeof(long)) / NR_FALLOC_PAGES;
zram->blk_bitmap = kvzalloc(bitmap_sz, GFP_KERNEL);
if (!zram->blk_bitmap) {
ret = -ENOMEM;
goto out;
}
if (zram_pin_backing_file(zram)) {
ret = -EINVAL;
goto out;
}
bitmap_sz = BITS_TO_LONGS(zram->nr_pages) * sizeof(long) / NR_ZWBS;
/* backing dev should be large enough for chunk writeback */
if (!bitmap_sz)
return -EINVAL;
zram->chunk_bitmap = kvzalloc(bitmap_sz, GFP_KERNEL);
if (!zram->chunk_bitmap) {
ret = -ENOMEM;
goto out;
}
zram->wbd = kthread_run(zram_wbd, zram, "%s_wbd", zram->disk->disk_name);
if (IS_ERR(zram->wbd)) {
ret = PTR_ERR(zram->wbd);
goto out;
}
g_zram = zram;
zram->wb_limit_enable = true;
sched_setscheduler(zram->wbd, SCHED_IDLE, &param);
return ret;
out:
if (zram->chunk_bitmap) {
kvfree(zram->chunk_bitmap);
zram->chunk_bitmap = NULL;
}
if (zram->blk_bitmap) {
kvfree(zram->blk_bitmap);
zram->blk_bitmap = NULL;
}
kvfree(zram->wb_table);
zram->wb_table = NULL;
return ret;
}
static void stop_lru_writeback(struct zram *zram)
{
if (!IS_ERR_OR_NULL(zram->wbd)) {
g_zram = NULL;
kthread_stop(zram->wbd);
zram->wbd = NULL;
}
}
static void deinit_lru_writeback(struct zram *zram)
{
unsigned long flags;
u8 *wb_table_tmp = zram->wb_table;
stop_lru_writeback(zram);
if (zram->chunk_bitmap) {
kvfree(zram->chunk_bitmap);
zram->chunk_bitmap = NULL;
}
if (zram->blk_bitmap) {
kvfree(zram->blk_bitmap);
zram->blk_bitmap = NULL;
}
spin_lock_irqsave(&zram->wb_table_lock, flags);
zram->wb_table = NULL;
spin_unlock_irqrestore(&zram->wb_table_lock, flags);
kvfree(wb_table_tmp);
}
#endif
static ssize_t writeback_limit_enable_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
u64 val;
ssize_t ret = -EINVAL;
if (kstrtoull(buf, 10, &val))
return ret;
down_read(&zram->init_lock);
spin_lock(&zram->wb_limit_lock);
zram->wb_limit_enable = val;
spin_unlock(&zram->wb_limit_lock);
up_read(&zram->init_lock);
ret = len;
return ret;
}
static ssize_t writeback_limit_enable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
bool val;
struct zram *zram = dev_to_zram(dev);
down_read(&zram->init_lock);
spin_lock(&zram->wb_limit_lock);
val = zram->wb_limit_enable;
spin_unlock(&zram->wb_limit_lock);
up_read(&zram->init_lock);
return scnprintf(buf, PAGE_SIZE, "%d\n", val);
}
static ssize_t writeback_limit_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
u64 val;
ssize_t ret = -EINVAL;
if (kstrtoull(buf, 10, &val))
return ret;
down_read(&zram->init_lock);
spin_lock(&zram->wb_limit_lock);
zram->bd_wb_limit = val;
spin_unlock(&zram->wb_limit_lock);
up_read(&zram->init_lock);
ret = len;
return ret;
}
static ssize_t writeback_limit_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
u64 val;
struct zram *zram = dev_to_zram(dev);
down_read(&zram->init_lock);
spin_lock(&zram->wb_limit_lock);
val = zram->bd_wb_limit;
spin_unlock(&zram->wb_limit_lock);
up_read(&zram->init_lock);
return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
}
static void reset_bdev(struct zram *zram)
{
struct block_device *bdev;
if (!zram->backing_dev)
return;
bdev = zram->bdev;
if (zram->old_block_size)
set_blocksize(bdev, zram->old_block_size);
blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
/* hope filp_close flush all of IO */
filp_close(zram->backing_dev, NULL);
zram->backing_dev = NULL;
zram->old_block_size = 0;
zram->bdev = NULL;
zram->disk->queue->backing_dev_info->capabilities |=
BDI_CAP_SYNCHRONOUS_IO;
kvfree(zram->bitmap);
zram->bitmap = NULL;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
deinit_lru_writeback(zram);
#endif
}
static ssize_t backing_dev_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct file *file;
struct zram *zram = dev_to_zram(dev);
char *p;
ssize_t ret;
down_read(&zram->init_lock);
file = zram->backing_dev;
if (!file) {
memcpy(buf, "none\n", 5);
up_read(&zram->init_lock);
return 5;
}
p = file_path(file, buf, PAGE_SIZE - 1);
if (IS_ERR(p)) {
ret = PTR_ERR(p);
goto out;
}
ret = strlen(p);
memmove(buf, p, ret);
buf[ret++] = '\n';
out:
up_read(&zram->init_lock);
return ret;
}
static ssize_t backing_dev_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
char *file_name;
size_t sz;
struct file *backing_dev = NULL;
struct inode *inode;
struct address_space *mapping;
unsigned int bitmap_sz, old_block_size = 0;
unsigned long nr_pages, *bitmap = NULL;
struct block_device *bdev = NULL;
int err;
struct zram *zram = dev_to_zram(dev);
file_name = kmalloc(PATH_MAX, GFP_KERNEL);
if (!file_name)
return -ENOMEM;
down_write(&zram->init_lock);
if (init_done(zram)) {
pr_info("Can't setup backing device for initialized device\n");
err = -EBUSY;
goto out;
}
strlcpy(file_name, buf, PATH_MAX);
/* ignore trailing newline */
sz = strlen(file_name);
if (sz > 0 && file_name[sz - 1] == '\n')
file_name[sz - 1] = 0x00;
backing_dev = filp_open(file_name, O_RDWR|O_LARGEFILE, 0);
if (IS_ERR(backing_dev)) {
err = PTR_ERR(backing_dev);
backing_dev = NULL;
goto out;
}
mapping = backing_dev->f_mapping;
inode = mapping->host;
/* Support only block device in this moment */
if (!S_ISBLK(inode->i_mode)) {
err = -ENOTBLK;
goto out;
}
bdev = bdgrab(I_BDEV(inode));
err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
if (err < 0) {
bdev = NULL;
goto out;
}
nr_pages = i_size_read(inode) >> PAGE_SHIFT;
bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long);
bitmap = kvzalloc(bitmap_sz, GFP_KERNEL);
if (!bitmap) {
err = -ENOMEM;
goto out;
}
old_block_size = block_size(bdev);
err = set_blocksize(bdev, PAGE_SIZE);
if (err)
goto out;
reset_bdev(zram);
zram->old_block_size = old_block_size;
zram->bdev = bdev;
zram->backing_dev = backing_dev;
zram->bitmap = bitmap;
zram->nr_pages = nr_pages;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
err = init_lru_writeback(zram);
if (err)
goto init_lru_writeback_fail;
#endif
/*
* With writeback feature, zram does asynchronous IO so it's no longer
* synchronous device so let's remove synchronous io flag. Othewise,
* upper layer(e.g., swap) could wait IO completion rather than
* (submit and return), which will cause system sluggish.
* Furthermore, when the IO function returns(e.g., swap_readpage),
* upper layer expects IO was done so it could deallocate the page
* freely but in fact, IO is going on so finally could cause
* use-after-free when the IO is really done.
*/
zram->disk->queue->backing_dev_info->capabilities &=
~BDI_CAP_SYNCHRONOUS_IO;
up_write(&zram->init_lock);
pr_info("setup backing device %s\n", file_name);
kfree(file_name);
return len;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
init_lru_writeback_fail:
zram->old_block_size = 0;
zram->bdev = NULL;
zram->backing_dev = NULL;
zram->bitmap = NULL;
zram->nr_pages = 0;
#endif
out:
if (bitmap)
kvfree(bitmap);
if (bdev)
blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
if (backing_dev)
filp_close(backing_dev, NULL);
up_write(&zram->init_lock);
kfree(file_name);
return err;
}
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
static unsigned long chunk_to_blk_idx(unsigned long idx)
{
return idx * NR_ZWBS;
}
static unsigned long blk_to_chunk_idx(unsigned long idx)
{
return idx / NR_ZWBS;
}
static unsigned long alloc_chunk_bdev(struct zram *zram)
{
unsigned long chunk_idx = 1;
unsigned long max_idx = zram->nr_pages / NR_ZWBS;
unsigned long blk_idx;
unsigned long flags;
int i;
retry:
/* skip 0 bit to confuse zram.handle = 0 */
chunk_idx = find_next_zero_bit(zram->chunk_bitmap, max_idx, chunk_idx);
if (chunk_idx == max_idx)
return 0;
spin_lock_irqsave(&zram->bitmap_lock, flags);
if (test_and_set_bit(chunk_idx, zram->chunk_bitmap)) {
spin_unlock_irqrestore(&zram->bitmap_lock, flags);
goto retry;
}
blk_idx = chunk_to_blk_idx(chunk_idx);
for (i = 0; i < NR_ZWBS; i++)
BUG_ON(test_and_set_bit(blk_idx + i, zram->bitmap));
spin_unlock_irqrestore(&zram->bitmap_lock, flags);
atomic64_add(NR_ZWBS, &zram->stats.bd_count);
count_vm_events(SQZR_COUNT, NR_ZWBS);
return blk_idx;
}
static unsigned long alloc_block_bdev(struct zram *zram)
{
unsigned long blk_idx = 1;
unsigned long flags;
retry:
/* skip 0 bit to confuse zram.handle = 0 */
blk_idx = find_next_zero_bit(zram->bitmap, zram->nr_pages, blk_idx);
if (blk_idx == zram->nr_pages)
return 0;
spin_lock_irqsave(&zram->bitmap_lock, flags);
if (test_and_set_bit(blk_idx, zram->bitmap)) {
spin_unlock_irqrestore(&zram->bitmap_lock, flags);
goto retry;
}
set_bit(blk_to_chunk_idx(blk_idx), zram->chunk_bitmap);
spin_unlock_irqrestore(&zram->bitmap_lock, flags);
atomic64_inc(&zram->stats.bd_count);
count_vm_events(SQZR_COUNT, 1);
return blk_idx;
}
static unsigned long try_alloc_block_bdev(struct zram *zram, int *nr_pages)
{
unsigned long blk_idx;
/* found free chunk, return blk_idx */
if (*nr_pages == NR_ZWBS) {
blk_idx = alloc_chunk_bdev(zram);
if (blk_idx)
return blk_idx;
}
*nr_pages = 1;
return alloc_block_bdev(zram);
}
static void free_chunk_bdev(struct zram *zram, unsigned long chunk_idx)
{
unsigned long blk_idx;
unsigned long flags;
int i;
blk_idx = chunk_to_blk_idx(chunk_idx);
spin_lock_irqsave(&zram->bitmap_lock, flags);
for (i = 0; i < NR_ZWBS; i++) {
if (test_bit(blk_idx + i, zram->bitmap)) {
spin_unlock_irqrestore(&zram->bitmap_lock, flags);
return;
}
}
clear_bit(chunk_idx, zram->chunk_bitmap);
spin_unlock_irqrestore(&zram->bitmap_lock, flags);
}
static void free_block_bdev(struct zram *zram, unsigned long blk_idx, bool ppr)
{
int was_set;
unsigned long flags;
spin_lock_irqsave(&zram->wb_table_lock, flags);
if (!zram->wb_table || zram->wb_table[blk_idx] == 0)
goto out;
zram->wb_table[blk_idx]--;
atomic64_dec(&zram->stats.bd_objcnt);
count_vm_events(SQZR_OBJCNT, -1);
if (ppr)
atomic64_dec(&zram->stats.bd_ppr_objcnt);
if (zram->wb_table[blk_idx] > 0) {
spin_unlock_irqrestore(&zram->wb_table_lock, flags);
return;
}
out:
spin_unlock_irqrestore(&zram->wb_table_lock, flags);
was_set = test_and_clear_bit(blk_idx, zram->bitmap);
WARN_ON_ONCE(!was_set);
atomic64_dec(&zram->stats.bd_count);
count_vm_events(SQZR_COUNT, -1);
if (ppr)
atomic64_dec(&zram->stats.bd_ppr_count);
free_chunk_bdev(zram, blk_to_chunk_idx(blk_idx));
}
#else
static unsigned long alloc_block_bdev(struct zram *zram)
{
unsigned long blk_idx = 1;
retry:
/* skip 0 bit to confuse zram.handle = 0 */
blk_idx = find_next_zero_bit(zram->bitmap, zram->nr_pages, blk_idx);
if (blk_idx == zram->nr_pages)
return 0;
if (test_and_set_bit(blk_idx, zram->bitmap))
goto retry;
atomic64_inc(&zram->stats.bd_count);
return blk_idx;
}
static void free_block_bdev(struct zram *zram, unsigned long blk_idx)
{
int was_set;
was_set = test_and_clear_bit(blk_idx, zram->bitmap);
WARN_ON_ONCE(!was_set);
atomic64_dec(&zram->stats.bd_count);
}
#endif
static void zram_page_end_io(struct bio *bio)
{
struct page *page = bio_first_page_all(bio);
page_endio(page, op_is_write(bio_op(bio)),
blk_status_to_errno(bio->bi_status));
bio_put(bio);
}
/*
* Returns 1 if the submission is successful.
*/
static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *parent)
{
struct bio *bio;
bio = bio_alloc(GFP_ATOMIC, 1);
if (!bio)
return -ENOMEM;
bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
bio_set_dev(bio, zram->bdev);
if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, bvec->bv_offset)) {
bio_put(bio);
return -EIO;
}
if (!parent) {
bio->bi_opf = REQ_OP_READ;
bio->bi_end_io = zram_page_end_io;
} else {
bio->bi_opf = parent->bi_opf;
bio_chain(bio, parent);
}
submit_bio(bio);
return 1;
}
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
static int zram_balance_ratio = 25; /* nand writeback ratio */
module_param(zram_balance_ratio, int, 0644);
static bool is_bdev_avail(struct zram *zram)
{
struct loop_device *lo;
struct inode *inode;
struct dentry *root;
struct kstatfs statbuf;
u64 min_free_blocks;
int ret;
if (!zram->bdev->bd_disk)
return false;
lo = zram->bdev->bd_disk->private_data;
if (!lo || !lo->lo_backing_file)
return false;
inode = lo->lo_backing_file->f_mapping->host;
root = inode->i_sb->s_root;
if (!root->d_sb->s_op->statfs)
return false;
ret = root->d_sb->s_op->statfs(root, &statbuf);
if (ret)
return false;
/*
* To guarantee "reserved block(133MB on Q-os)" for system,
* SQZR is triggered only when devices have enough storage free space
* more than SZ_1G or reserved block * 2.
*/
min_free_blocks = max_t(u64, SZ_1G / statbuf.f_bsize,
(statbuf.f_bfree - statbuf.f_bavail) * 2);
if (statbuf.f_bavail < min_free_blocks)
return false;
return true;
}
static inline bool zram_throttle_writeback_size(struct zram *zram)
{
long objcnt = atomic64_read(&zram->stats.bd_objcnt);
if ((unsigned long)objcnt >= zram->nr_pages * 4)
return true;
else
return false;
}
static bool zram_wb_available(struct zram *zram)
{
if (!zram->wb_table)
return false;
spin_lock(&zram->wb_limit_lock);
if (zram->wb_limit_enable && !zram->bd_wb_limit) {
spin_unlock(&zram->wb_limit_lock);
return false;
}
spin_unlock(&zram->wb_limit_lock);
if (zram_throttle_writeback_size(zram))
return false;
return true;
}
static u32 entry_to_index(struct zram *zram, struct zram_table_entry *entry)
{
return (u32)(((unsigned long)entry - (unsigned long)zram->table) /
sizeof(struct zram_table_entry));
}
#define SKIP 1
#define ABORT 2
static int zram_try_mark_page(struct zram *zram, u32 index)
{
/* invalid index */
if (index >= (zram->disksize >> PAGE_SHIFT))
return ABORT;
if (!zram_slot_trylock(zram, index))
return SKIP;
if (!zram_allocated(zram, index) ||
zram_test_flag(zram, index, ZRAM_UNDER_PPR)) {
zram_slot_unlock(zram, index);
return ABORT;
} else if (zram_test_flag(zram, index, ZRAM_UNDER_WB)) {
zram_slot_unlock(zram, index);
return SKIP;
}
zram_set_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
return 0;
}
void free_zwbs(struct zwbs **zwbs)
{
int i;
for (i = 0; i < NR_ZWBS; i++) {
if (!zwbs[i])
return;
if (zwbs[i]->page)
__free_page(zwbs[i]->page);
kfree(zwbs[i]);
}
}
int alloc_zwbs(struct zwbs **zwbs)
{
int i;
for (i = 0; i < NR_ZWBS; i++) {
zwbs[i] = kzalloc(sizeof(struct zwbs), GFP_KERNEL);
if (!zwbs[i])
goto out;
zwbs[i]->page = alloc_page(GFP_KERNEL);
if (!zwbs[i]->page)
goto out;
}
return 0;
out:
free_zwbs(zwbs);
return -ENOMEM;
}
bool zram_is_app_launch(void)
{
return is_app_launch;
}
#define ZRAM_WBD_INTERVAL 10 * HZ
static bool zram_should_writeback(struct zram *zram,
unsigned long pages, bool trigger)
{
unsigned long stored = atomic64_read(&zram->stats.lru_pages);
unsigned long writtenback = atomic64_read(&zram->stats.bd_objcnt) -
atomic64_read(&zram->stats.bd_ppr_objcnt) -
atomic64_read(&zram->stats.bd_expire);
unsigned long min_stored_byte;
int writtenback_ratio = stored ? (writtenback * 100) / stored : 0;
int min_writtenback_ratio = zram_balance_ratio;
int margin = max_t(int, 1, zram_balance_ratio / 10);
int max_pages = CONFIG_ZRAM_LRU_WRITEBACK_LIMIT;
static unsigned long time_stamp;
bool ret = true;
/* avoid app launch time */
if (is_app_launch)
return false;
/* stop thread when writtenback enough */
if (pages > max_pages)
return false;
/* do not trigger again before time interval */
if (trigger && time_is_after_jiffies(time_stamp))
return false;
if (trigger)
min_writtenback_ratio -= margin;
else
min_writtenback_ratio += margin;
if (min_writtenback_ratio < writtenback_ratio)
ret = false;
if (zram->disksize / 4 > SZ_1G)
min_stored_byte = SZ_1G;
else
min_stored_byte = zram->disksize / 4;
if ((stored << PAGE_SHIFT) < min_stored_byte)
ret = false;
if (trigger && ret == true)
time_stamp = jiffies + ZRAM_WBD_INTERVAL;
return ret;
}
static void try_wakeup_zram_wbd(struct zram *zram)
{
unsigned long bd_count;
if (zram->backing_dev && !zram->wbd_running &&
zram_wb_available(zram) &&
zram_should_writeback(zram, 0, true) &&
is_bdev_avail(zram)) {
bd_count = atomic64_read(&zram->stats.bd_count);
/* wakeup zram_wbd with enough free blocks */
if (zram->nr_pages - bd_count < NR_ZWBS)
return;
zram->wbd_running = true;
wake_up(&zram->wbd_wait);
}
}
static int zram_app_launch_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
is_app_launch = action ? true : false;
if (!is_app_launch && g_zram)
try_wakeup_zram_wbd(g_zram);
return 0;
}
static struct notifier_block zram_app_launch_nb = {
.notifier_call = zram_app_launch_notifier,
};
static void mark_end_of_page(struct zwbs *zwbs)
{
struct zram_wb_header *zhdr;
struct page *page = zwbs->page;
int offset = zwbs->off;
void *mem;
if (offset + sizeof(struct zram_wb_header) < PAGE_SIZE) {
mem = kmap_atomic(page);
zhdr = (struct zram_wb_header *)(mem + offset);
zhdr->index = UINT_MAX;
zhdr->size = 0;
kunmap_atomic(mem);
}
}
static int zram_writeback_fill_page(struct zram *zram, u32 index,
struct zwbs *zwbs)
{
struct zram_wb_header *zhdr;
struct page *page = zwbs->page;
int offset = zwbs->off;
unsigned long handle;
void *src, *dst;
int ret, size;
int header_sz = 0;
zram_slot_lock(zram, index);
if (!zram_allocated(zram, index) ||
!zram_test_flag(zram, index, ZRAM_IDLE) ||
zram_test_flag(zram, index, ZRAM_WB) ||
zram_test_flag(zram, index, ZRAM_SAME) ||
zram_test_flag(zram, index, ZRAM_UNDER_WB)) {
zram_slot_unlock(zram, index);
return 0;
}
size = zram_get_obj_size(zram, index);
if (size != PAGE_SIZE)
header_sz = sizeof(struct zram_wb_header);
if (offset + header_sz + size > PAGE_SIZE) {
zram_slot_unlock(zram, index);
return -ENOSPC;
}
/*
* Clearing ZRAM_UNDER_WB is duty of caller.
* IOW, zram_free_page never clear it.
*/
zram_set_flag(zram, index, ZRAM_UNDER_WB);
/* Need for hugepage writeback racing */
zram_set_flag(zram, index, ZRAM_IDLE);
handle = zram_get_element(zram, index);
if (!handle) {
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
return -ENOENT;
}
src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
dst = kmap_atomic(page);
if (size != PAGE_SIZE) {
zhdr = (struct zram_wb_header *)(dst + offset);
zhdr->index = index;
zhdr->size = size;
dst = (u8 *)(zhdr + 1);
}
memcpy(dst, src, size);
ret = size;
kunmap_atomic(dst);
zs_unmap_object(zram->mem_pool, handle);
zram_slot_unlock(zram, index);
return ret;
}
static void zram_writeback_clear_flag(struct zram *zram, struct zwbs *zwbs)
{
struct zram_wb_entry *entry = zwbs->entry;
unsigned int count = zwbs->cnt;
unsigned long index;
int i;
for (i = 0; i < count; i++) {
index = entry[i].index;
zram_slot_lock(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
zram_clear_flag(zram, index, ZRAM_UNDER_PPR);
zram_slot_unlock(zram, index);
}
}
static void zram_update_max_stats(struct zram *zram)
{
unsigned long bd_count, bd_size, bd_ppr_count, bd_ppr_size;
bd_count = atomic64_read(&zram->stats.bd_count);
if (bd_count <= atomic64_read(&zram->stats.bd_max_count))
return;
bd_size = atomic64_read(&zram->stats.bd_size);
bd_ppr_count = atomic64_read(&zram->stats.bd_ppr_count);
bd_ppr_size = atomic64_read(&zram->stats.bd_ppr_size);
atomic64_set(&zram->stats.bd_max_count, bd_count);
atomic64_set(&zram->stats.bd_max_size, bd_size);
atomic64_set(&zram->stats.bd_ppr_max_count, bd_ppr_count);
atomic64_set(&zram->stats.bd_ppr_max_size, bd_ppr_size);
}
static void zram_reset_stats(struct zram *zram)
{
atomic64_set(&zram->stats.bd_max_count, 0);
atomic64_set(&zram->stats.bd_max_size, 0);
atomic64_set(&zram->stats.bd_ppr_max_count, 0);
atomic64_set(&zram->stats.bd_ppr_max_size, 0);
}
static void zram_writeback_done(struct zram *zram,
struct zwbs *zwbs, unsigned long blk_idx, bool ppr)
{
unsigned long index;
unsigned int offset;
unsigned int size;
unsigned int count = zwbs->cnt;
struct zram_wb_entry *entry = zwbs->entry;
int i;
unsigned long flags;
spin_lock_irqsave(&zram->wb_table_lock, flags);
if (!zram->wb_table) {
spin_unlock_irqrestore(&zram->wb_table_lock, flags);
return;
}
zram->wb_table[blk_idx] = count;
spin_unlock_irqrestore(&zram->wb_table_lock, flags);
atomic64_add(count, &zram->stats.bd_objwrites);
atomic64_add(count, &zram->stats.bd_objcnt);
count_vm_events(SQZR_OBJCNT, count);
if (ppr)
atomic64_add(count, &zram->stats.bd_ppr_objcnt);
for (i = 0; i < count; i++) {
index = entry[i].index;
offset = entry[i].offset;
size = entry[i].size;
/*
* We released zram_slot_lock so need to check if the slot was
* changed. If there is freeing for the slot, we can catch it
* easily by zram_allocated.
* A subtle case is the slot is freed/reallocated/marked as
* ZRAM_IDLE again. To close the race, idle_store doesn't
* mark ZRAM_IDLE once it found the slot was ZRAM_UNDER_WB.
* Thus, we could close the race by checking ZRAM_IDLE bit.
*/
zram_slot_lock(zram, index);
if (!zram_allocated(zram, index) ||
!zram_test_flag(zram, index, ZRAM_IDLE)) {
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
zram_clear_flag(zram, index, ZRAM_UNDER_PPR);
free_block_bdev(zram, blk_idx, ppr);
zram_slot_unlock(zram, index);
continue;
}
zram_free_page(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_set_flag(zram, index, ZRAM_WB);
atomic64_add(size, &zram->stats.bd_size);
if (ppr) {
zram_set_flag(zram, index, ZRAM_PPR);
atomic64_add(size, &zram->stats.bd_ppr_size);
}
/* record element as "blk_idx|offset|size" */
if (size == PAGE_SIZE)
size = 0;
zram_set_element(zram, index,
(blk_idx << (PAGE_SHIFT * 2)) | (offset << PAGE_SHIFT) | size);
zram_slot_unlock(zram, index);
atomic64_inc(&zram->stats.pages_stored);
}
}
static void zram_writeback_end_io(struct bio *bio)
{
if (g_zram && !g_zram->io_complete) {
g_zram->io_complete = true;
wake_up(&g_zram->wbd_wait);
}
}
static int zram_writeback_page(struct zram *zram, struct zwbs **zwbs,
int nr_to_write, bool sync, bool ppr)
{
struct bio bio;
struct bio_vec *bio_vec;
unsigned long blk_idx;
int ret = 0;
int i, idx = 0;
int nr_pages = nr_to_write;
retry:
blk_idx = try_alloc_block_bdev(zram, &nr_pages);
if (!blk_idx) {
ret = -ENOSPC;
goto out;
}
/* fallocate 2MB block if not allocated yet */
fallocate_block(zram, blk_idx);
if (ppr)
atomic64_add(nr_pages, &zram->stats.bd_ppr_count);
bio_vec = kmalloc_array(nr_pages, sizeof(struct bio_vec), GFP_KERNEL);
if (!bio_vec) {
ret = -ENOSPC;
goto out;
}
bio_init(&bio, bio_vec, nr_pages);
bio_set_dev(&bio, zram->bdev);
bio.bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
bio.bi_opf = REQ_OP_WRITE;
for (i = 0; i < nr_pages; i++)
bio_add_page(&bio, zwbs[idx + i]->page, PAGE_SIZE, 0);
if (sync) {
ret = submit_bio_wait(&bio);
} else {
bio.bi_end_io = zram_writeback_end_io;
zram->io_complete = false;
submit_bio(&bio);
wait_event(zram->wbd_wait, zram->io_complete);
ret = blk_status_to_errno(bio.bi_status);
}
kfree(bio_vec);
out:
if (!ret) {
for (i = 0; i < nr_pages; i++)
zram_writeback_done(zram, zwbs[idx + i], blk_idx + i, ppr);
zram_update_max_stats(zram);
atomic64_add(nr_pages, &zram->stats.bd_writes);
count_vm_events(SQZR_WRITE, nr_pages);
if (ppr)
atomic64_add(nr_pages, &zram->stats.bd_ppr_writes);
spin_lock(&zram->wb_limit_lock);
if (zram->wb_limit_enable) {
if (zram->bd_wb_limit > nr_pages)
zram->bd_wb_limit -= nr_pages;
else
zram->bd_wb_limit = 0;
}
spin_unlock(&zram->wb_limit_lock);
idx += nr_pages;
if (idx < nr_to_write)
goto retry;
} else {
if (blk_idx)
for (i = 0; i < nr_pages; i++)
free_block_bdev(zram, blk_idx + i, ppr);
/* free all remaining entries when error */
for (i = idx; i < nr_to_write; i++)
zram_writeback_clear_flag(zram, zwbs[i]);
}
return ret;
}
static int zram_comp_writeback_index(struct zram *zram, u32 index,
struct zwbs **zwbs, int *idx, bool sync, bool ppr)
{
int size, ret = 0;
int i = *idx, j;
retry:
size = zram_writeback_fill_page(zram, index, zwbs[i]);
if (size > 0) {
struct zram_wb_entry *entry = zwbs[i]->entry;
entry[zwbs[i]->cnt].index = index;
entry[zwbs[i]->cnt].offset = zwbs[i]->off;
entry[zwbs[i]->cnt].size = size;
zwbs[i]->off += size;
if (size < PAGE_SIZE)
zwbs[i]->off += sizeof(struct zram_wb_header);
zwbs[i]->cnt++;
}
/* writeback if page is full/entry is full */
if (size == -ENOSPC || zwbs[i]->cnt == ZRAM_WB_THRESHOLD) {
mark_end_of_page(zwbs[i]);
i = (i + 1) % NR_ZWBS;
if (i > 0)
goto retry;
ret = zram_writeback_page(zram, zwbs, NR_ZWBS, sync, ppr);
for (j = 0; j < NR_ZWBS; j++) {
zwbs[j]->cnt = 0;
zwbs[j]->off = 0;
}
if (ret == 0 && size == -ENOSPC)
goto retry;
}
*idx = i;
return ret;
}
static void zram_comp_writeback(struct zram *zram)
{
struct zwbs *zwbs[NR_ZWBS];
unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
unsigned long index;
int idx = 0;
if (alloc_zwbs(zwbs)) {
pr_info("%s alloc_zwbs failed", __func__);
return;
}
for (index = 0; index < nr_pages; index++) {
if (!zram_wb_available(zram))
break;
if (zram_comp_writeback_index(zram, index, zwbs, &idx, true, false))
break;
}
free_zwbs(zwbs);
pr_info("%s done", __func__);
}
static int zram_wbd(void *p)
{
struct zram *zram = (struct zram *)p;
struct zram_table_entry *zram_entry, *n;
struct zwbs *zwbs[NR_ZWBS];
u32 index;
int idx = 0;
int ret;
set_freezable();
if (alloc_zwbs(zwbs)) {
pr_info("%s alloc_zwbs failed", __func__);
return 0;
}
while (!kthread_should_stop()) {
unsigned long nr_pages = 0;
wait_event_freezable(zram->wbd_wait,
zram->wbd_running || kthread_should_stop());
list_for_each_entry_safe(zram_entry, n, &zram->list, lru_list) {
if (try_to_freeze() || kthread_should_stop())
break;
if (!zram_wb_available(zram))
break;
index = entry_to_index(zram, zram_entry);
ret = zram_try_mark_page(zram, index);
if (!ret) {
if (zram_comp_writeback_index(zram, index,
zwbs, &idx, false, false))
break;
} else if (ret == ABORT) {
n = list_first_entry(&zram->list,
struct zram_table_entry, lru_list);
}
if (!zram_should_writeback(zram, ++nr_pages, false))
break;
}
zram->wbd_running = false;
pr_info("%s done", __func__);
}
free_zwbs(zwbs);
return 0;
}
int is_writeback_entry(swp_entry_t entry)
{
struct zram *zram;
struct swap_info_struct *sis = swap_info[swp_type(entry)];
unsigned long index = swp_offset(entry);
int ret = 0;
if (!(sis->flags & SWP_BLKDEV))
return 0;
zram = sis->bdev->bd_disk->private_data;
zram_slot_lock(zram, index);
if (zram_allocated(zram, index) &&
zram_test_flag(zram, index, ZRAM_WB))
ret = 1;
zram_slot_unlock(zram, index);
return ret;
}
void swap_add_to_list(struct list_head *list, swp_entry_t entry)
{
struct zram *zram;
struct swap_info_struct *sis = swap_info[swp_type(entry)];
unsigned long index = swp_offset(entry);
unsigned long flags;
if (!(sis->flags & SWP_BLKDEV))
return;
zram = sis->bdev->bd_disk->private_data;
if (zram != g_zram)
return;
if (!is_bdev_avail(zram))
return;
if (!zram_wb_available(zram))
return;
if (!zram_slot_trylock(zram, index))
return;
if (zram_allocated(zram, index) &&
!zram_test_flag(zram, index, ZRAM_IDLE) &&
!zram_test_flag(zram, index, ZRAM_WB) &&
!zram_test_flag(zram, index, ZRAM_SAME) &&
!zram_test_flag(zram, index, ZRAM_UNDER_WB) &&
!zram_test_flag(zram, index, ZRAM_UNDER_PPR)) {
zram_set_flag(zram, index, ZRAM_IDLE);
zram_set_flag(zram, index, ZRAM_UNDER_PPR);
spin_lock_irqsave(&zram->list_lock, flags);
if (!list_empty(&zram->table[index].lru_list)) {
list_move(&zram->table[index].lru_list, list);
if (zram_test_flag(zram, index, ZRAM_LRU)) {
zram_clear_flag(zram, index, ZRAM_LRU);
atomic64_dec(&zram->stats.lru_pages);
}
}
spin_unlock_irqrestore(&zram->list_lock, flags);
}
zram_slot_unlock(zram, index);
}
void swap_writeback_list(struct zwbs **zwbs, struct list_head *list)
{
struct zram *zram = g_zram;
struct zram_table_entry *zram_entry;
u32 index;
static int idx = 0;
unsigned long flags;
bool skip = false;
if (list == NULL) {
if (idx > 0 || zwbs[idx]->cnt > 0) {
mark_end_of_page(zwbs[idx]);
if (zwbs[idx]->cnt > 0)
idx++;
zram_writeback_page(zram, zwbs, idx, true, true);
}
idx = 0;
return;
}
while (!list_empty(list)) {
zram_entry = list_first_entry(list,
typeof(struct zram_table_entry), lru_list);
index = entry_to_index(zram, zram_entry);
if (!skip) {
if (!zram_wb_available(zram))
skip = true;
else if (zram_comp_writeback_index(zram, index,
zwbs, &idx, true, true))
skip = true;
}
zram_slot_lock(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_PPR);
spin_lock_irqsave(&zram->list_lock, flags);
if (!list_empty(&zram->table[index].lru_list))
list_del_init(&zram->table[index].lru_list);
spin_unlock_irqrestore(&zram->list_lock, flags);
zram_slot_unlock(zram, index);
}
}
#endif
#define HUGE_WRITEBACK 1
#define IDLE_WRITEBACK 2
static ssize_t writeback_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
unsigned long index;
struct bio bio;
struct bio_vec bio_vec;
struct page *page;
ssize_t ret, sz;
char mode_buf[8];
int mode = -1;
unsigned long blk_idx = 0;
sz = strscpy(mode_buf, buf, sizeof(mode_buf));
if (sz <= 0)
return -EINVAL;
/* ignore trailing newline */
if (mode_buf[sz - 1] == '\n')
mode_buf[sz - 1] = 0x00;
if (!strcmp(mode_buf, "idle"))
mode = IDLE_WRITEBACK;
else if (!strcmp(mode_buf, "huge"))
mode = HUGE_WRITEBACK;
if (mode == -1)
return -EINVAL;
down_read(&zram->init_lock);
if (!init_done(zram)) {
ret = -EINVAL;
goto release_init_lock;
}
if (!zram->backing_dev) {
ret = -ENODEV;
goto release_init_lock;
}
page = alloc_page(GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
goto release_init_lock;
}
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
if (mode == IDLE_WRITEBACK) {
if (is_bdev_avail(zram))
zram_comp_writeback(zram);
ret = len;
__free_page(page);
goto release_init_lock;
}
#endif
for (index = 0; index < nr_pages; index++) {
struct bio_vec bvec;
bvec.bv_page = page;
bvec.bv_len = PAGE_SIZE;
bvec.bv_offset = 0;
spin_lock(&zram->wb_limit_lock);
if (zram->wb_limit_enable && !zram->bd_wb_limit) {
spin_unlock(&zram->wb_limit_lock);
ret = -EIO;
break;
}
spin_unlock(&zram->wb_limit_lock);
if (!blk_idx) {
blk_idx = alloc_block_bdev(zram);
if (!blk_idx) {
ret = -ENOSPC;
break;
}
}
zram_slot_lock(zram, index);
if (!zram_allocated(zram, index))
goto next;
if (zram_test_flag(zram, index, ZRAM_WB) ||
zram_test_flag(zram, index, ZRAM_SAME) ||
zram_test_flag(zram, index, ZRAM_UNDER_WB))
goto next;
if (mode == IDLE_WRITEBACK &&
!zram_test_flag(zram, index, ZRAM_IDLE))
goto next;
if (mode == HUGE_WRITEBACK &&
!zram_test_flag(zram, index, ZRAM_HUGE))
goto next;
/*
* Clearing ZRAM_UNDER_WB is duty of caller.
* IOW, zram_free_page never clear it.
*/
zram_set_flag(zram, index, ZRAM_UNDER_WB);
/* Need for hugepage writeback racing */
zram_set_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
if (zram_bvec_read(zram, &bvec, index, 0, NULL)) {
zram_slot_lock(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
continue;
}
bio_init(&bio, &bio_vec, 1);
bio_set_dev(&bio, zram->bdev);
bio.bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
bio.bi_opf = REQ_OP_WRITE | REQ_SYNC;
bio_add_page(&bio, bvec.bv_page, bvec.bv_len,
bvec.bv_offset);
/*
* XXX: A single page IO would be inefficient for write
* but it would be not bad as starter.
*/
ret = submit_bio_wait(&bio);
if (ret) {
zram_slot_lock(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
continue;
}
atomic64_inc(&zram->stats.bd_writes);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
count_vm_event(SQZR_WRITE);
#endif
/*
* We released zram_slot_lock so need to check if the slot was
* changed. If there is freeing for the slot, we can catch it
* easily by zram_allocated.
* A subtle case is the slot is freed/reallocated/marked as
* ZRAM_IDLE again. To close the race, idle_store doesn't
* mark ZRAM_IDLE once it found the slot was ZRAM_UNDER_WB.
* Thus, we could close the race by checking ZRAM_IDLE bit.
*/
zram_slot_lock(zram, index);
if (!zram_allocated(zram, index) ||
!zram_test_flag(zram, index, ZRAM_IDLE)) {
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
goto next;
}
zram_free_page(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_set_flag(zram, index, ZRAM_WB);
zram_set_element(zram, index, blk_idx << (PAGE_SHIFT * 2));
blk_idx = 0;
atomic64_inc(&zram->stats.pages_stored);
atomic64_inc(&zram->stats.bd_objcnt);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
count_vm_event(SQZR_OBJCNT);
#endif
spin_lock(&zram->wb_limit_lock);
if (zram->wb_limit_enable && zram->bd_wb_limit > 0)
zram->bd_wb_limit -= 1UL << (PAGE_SHIFT - 12);
spin_unlock(&zram->wb_limit_lock);
next:
zram_slot_unlock(zram, index);
}
if (blk_idx)
free_block_bdev(zram, blk_idx, false);
ret = len;
__free_page(page);
release_init_lock:
up_read(&zram->init_lock);
return ret;
}
struct zram_work {
struct work_struct work;
struct zram *zram;
unsigned long entry;
struct bio *bio;
struct bio_vec bvec;
};
#if PAGE_SIZE != 4096
static void zram_sync_read(struct work_struct *work)
{
struct zram_work *zw = container_of(work, struct zram_work, work);
struct zram *zram = zw->zram;
unsigned long entry = zw->entry;
struct bio *bio = zw->bio;
read_from_bdev_async(zram, &zw->bvec, entry, bio);
}
/*
* Block layer want one ->make_request_fn to be active at a time
* so if we use chained IO with parent IO in same context,
* it's a deadlock. To avoid, it, it uses worker thread context.
*/
static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *bio)
{
struct zram_work work;
work.bvec = *bvec;
work.zram = zram;
work.entry = entry;
work.bio = bio;
INIT_WORK_ONSTACK(&work.work, zram_sync_read);
queue_work(system_unbound_wq, &work.work);
flush_work(&work.work);
destroy_work_on_stack(&work.work);
return 1;
}
#else
static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *bio)
{
WARN_ON(1);
return -EIO;
}
#endif
static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *parent, bool sync)
{
atomic64_inc(&zram->stats.bd_reads);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
count_vm_event(SQZR_READ);
#endif
if (sync)
return read_from_bdev_sync(zram, bvec, entry, parent);
else
return read_from_bdev_async(zram, bvec, entry, parent);
}
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
static void zram_handle_remain(struct zram *zram, struct page *page,
unsigned int blk_idx)
{
struct zram_wb_header *zhdr;
unsigned long alloced_pages;
unsigned long handle;
unsigned int offset = 0;
unsigned int size;
u32 index;
u8 *mem, *src, *dst;
mem = kmap_atomic(page);
while (offset + sizeof(struct zram_wb_header) < PAGE_SIZE) {
zhdr = (struct zram_wb_header *)(mem + offset);
index = zhdr->index;
size = zhdr->size;
/* invalid index */
if (index >= (zram->disksize >> PAGE_SHIFT))
break;
if (!zram_slot_trylock(zram, index))
goto next;
if (!zram_allocated(zram, index) ||
!zram_test_flag(zram, index, ZRAM_WB) ||
zram_test_flag(zram, index, ZRAM_READ_BDEV)) {
zram_slot_unlock(zram, index);
goto next;
}
handle = zram_get_element(zram, index);
if ((handle >> (PAGE_SHIFT * 2)) != blk_idx ||
((handle >> PAGE_SHIFT) & (PAGE_SIZE - 1)) != offset ||
(handle & (PAGE_SIZE - 1)) != size) {
zram_slot_unlock(zram, index);
goto next;
}
atomic64_inc(&zram->stats.bd_objreads);
handle = zs_malloc(zram->mem_pool, size,
__GFP_KSWAPD_RECLAIM |
__GFP_NOWARN |
__GFP_HIGHMEM |
__GFP_MOVABLE |
__GFP_CMA);
if (!handle) {
zram_slot_unlock(zram, index);
break;
}
alloced_pages = zs_get_total_pages(zram->mem_pool);
update_used_max(zram, alloced_pages);
dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);
src = (u8 *)(zhdr + 1);
memcpy(dst, src, size);
zs_unmap_object(zram->mem_pool, handle);
atomic64_add(size, &zram->stats.compr_data_size);
zram_free_page(zram, index);
zram_set_element(zram, index, handle);
zram_set_obj_size(zram, index, size);
zram_slot_unlock(zram, index);
atomic64_inc(&zram->stats.pages_stored);
next:
offset += (size + sizeof(struct zram_wb_header));
}
kunmap_atomic(mem);
free_block_bdev(zram, blk_idx, false);
atomic64_inc(&zram->stats.bd_objcnt);
count_vm_event(SQZR_OBJCNT);
}
static void zram_handle_comp_page(struct work_struct *work)
{
struct zram_wb_work *zw = container_of(work, struct zram_wb_work, work);
struct zram_wb_header *zhdr;
struct zram *zram = zw->zram;
struct zcomp_strm *zstrm;
struct page *src_page = zw->src_page;
struct page *dst_page = zw->dst_page;
struct bio *bio = zw->bio;
unsigned long handle;
unsigned int blk_idx = zw->handle >> (PAGE_SHIFT * 2);
unsigned int offset = (zw->handle >> PAGE_SHIFT) & (PAGE_SIZE - 1);
unsigned int size = zw->handle & (PAGE_SIZE - 1);
u8 *src, *dst;
int ret;
unsigned long flags;
src = kmap_atomic(src_page);
zhdr = (struct zram_wb_header *)(src + offset);
handle = zhdr->index;
BUG_ON(zhdr->size != size);
dst = kmap_atomic(dst_page);
zstrm = zcomp_stream_get(zram->comp);
ret = zcomp_decompress(zstrm,
src + offset + sizeof(struct zram_wb_header), size, dst);
zcomp_stream_put(zram->comp);
if (ret) {
pr_err("%s Decompression failed! err=%d offset=%u size=%u addr=%p\n",
__func__, ret, offset, size, src);
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
src, PAGE_SIZE, 1);
BUG_ON(ret);
}
kunmap_atomic(dst);
kunmap_atomic(src);
zram_slot_lock(zram, handle);
zram_clear_flag(zram, handle, ZRAM_READ_BDEV);
zram_slot_unlock(zram, handle);
/* increment refcount to prevent freeing block */
spin_lock_irqsave(&zram->wb_table_lock, flags);
if (zram->wb_table)
zram->wb_table[blk_idx]++;
spin_unlock_irqrestore(&zram->wb_table_lock, flags);
page_endio(dst_page, op_is_write(bio_op(bio)),
blk_status_to_errno(bio->bi_status));
bio_put(bio);
zram_handle_remain(zram, src_page, blk_idx);
kfree(zw);
__free_page(src_page);
}
static void zram_comp_page_end_io(struct bio *bio)
{
struct page *page = bio->bi_io_vec[0].bv_page;
struct zram_wb_work *zw = (struct zram_wb_work *)page_private(page);
INIT_WORK(&zw->work, zram_handle_comp_page);
schedule_work(&zw->work);
}
static int read_comp_from_bdev(struct zram *zram, struct bio_vec *bvec,
unsigned long handle, struct bio *parent)
{
struct zram_wb_work *zw;
struct bio *bio;
struct page *page;
unsigned long blk_idx = handle >> (PAGE_SHIFT * 2);
atomic64_inc(&zram->stats.bd_reads);
count_vm_event(SQZR_READ);
bio = bio_alloc(GFP_ATOMIC, 1);
if (!bio)
return -ENOMEM;
page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
if (!page) {
pr_info("%s failed to alloc page", __func__);
bio_put(bio);
return -ENOMEM;
}
zw = kzalloc(sizeof(struct zram_wb_work), GFP_ATOMIC);
if (!zw) {
__free_page(page);
bio_put(bio);
return -ENOMEM;
}
zw->src_page = page;
zw->dst_page = bvec->bv_page;
zw->zram = zram;
zw->bio = bio;
zw->handle = handle;
set_page_private(page, (unsigned long)zw);
bio->bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
bio_set_dev(bio, zram->bdev);
if (!bio_add_page(bio, page, PAGE_SIZE, 0)) {
kfree(zw);
__free_page(page);
bio_put(bio);
return -EIO;
}
if (!parent) {
bio->bi_opf = REQ_OP_READ;
bio->bi_end_io = zram_comp_page_end_io;
} else {
bio->bi_opf = parent->bi_opf;
bio_chain(bio, parent);
}
submit_bio(bio);
return 1;
}
#endif
#else
static inline void reset_bdev(struct zram *zram) {};
static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
unsigned long entry, struct bio *parent, bool sync)
{
return -EIO;
}
static void free_block_bdev(struct zram *zram, unsigned long blk_idx) {};
#endif
#ifdef CONFIG_ZRAM_MEMORY_TRACKING
static struct dentry *zram_debugfs_root;
static void zram_debugfs_create(void)
{
zram_debugfs_root = debugfs_create_dir("zram", NULL);
}
static void zram_debugfs_destroy(void)
{
debugfs_remove_recursive(zram_debugfs_root);
}
static void zram_accessed(struct zram *zram, u32 index)
{
zram_clear_flag(zram, index, ZRAM_IDLE);
zram->table[index].ac_time = ktime_get_boottime();
}
static ssize_t read_block_state(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
char *kbuf;
ssize_t index, written = 0;
struct zram *zram = file->private_data;
unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
struct timespec64 ts;
kbuf = kvmalloc(count, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
down_read(&zram->init_lock);
if (!init_done(zram)) {
up_read(&zram->init_lock);
kvfree(kbuf);
return -EINVAL;
}
for (index = *ppos; index < nr_pages; index++) {
int copied;
zram_slot_lock(zram, index);
if (!zram_allocated(zram, index))
goto next;
ts = ktime_to_timespec64(zram->table[index].ac_time);
copied = snprintf(kbuf + written, count,
"%12zd %12lld.%06lu %c%c%c%c\n",
index, (s64)ts.tv_sec,
ts.tv_nsec / NSEC_PER_USEC,
zram_test_flag(zram, index, ZRAM_SAME) ? 's' : '.',
zram_test_flag(zram, index, ZRAM_WB) ? 'w' : '.',
zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.',
zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.');
if (count < copied) {
zram_slot_unlock(zram, index);
break;
}
written += copied;
count -= copied;
next:
zram_slot_unlock(zram, index);
*ppos += 1;
}
up_read(&zram->init_lock);
if (copy_to_user(buf, kbuf, written))
written = -EFAULT;
kvfree(kbuf);
return written;
}
static const struct file_operations proc_zram_block_state_op = {
.open = simple_open,
.read = read_block_state,
.llseek = default_llseek,
};
static void zram_debugfs_register(struct zram *zram)
{
if (!zram_debugfs_root)
return;
zram->debugfs_dir = debugfs_create_dir(zram->disk->disk_name,
zram_debugfs_root);
debugfs_create_file("block_state", 0400, zram->debugfs_dir,
zram, &proc_zram_block_state_op);
}
static void zram_debugfs_unregister(struct zram *zram)
{
debugfs_remove_recursive(zram->debugfs_dir);
}
#else
static void zram_debugfs_create(void) {};
static void zram_debugfs_destroy(void) {};
static void zram_accessed(struct zram *zram, u32 index)
{
zram_clear_flag(zram, index, ZRAM_IDLE);
};
static void zram_debugfs_register(struct zram *zram) {};
static void zram_debugfs_unregister(struct zram *zram) {};
#endif
/*
* We switched to per-cpu streams and this attr is not needed anymore.
* However, we will keep it around for some time, because:
* a) we may revert per-cpu streams in the future
* b) it's visible to user space and we need to follow our 2 years
* retirement rule; but we already have a number of 'soon to be
* altered' attrs, so max_comp_streams need to wait for the next
* layoff cycle.
*/
static ssize_t max_comp_streams_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return scnprintf(buf, PAGE_SIZE, "%d\n", num_online_cpus());
}
static ssize_t max_comp_streams_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
return len;
}
static ssize_t comp_algorithm_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
size_t sz;
struct zram *zram = dev_to_zram(dev);
down_read(&zram->init_lock);
sz = zcomp_available_show(zram->compressor, buf);
up_read(&zram->init_lock);
return sz;
}
static ssize_t comp_algorithm_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
char compressor[ARRAY_SIZE(zram->compressor)];
size_t sz;
strlcpy(compressor, buf, sizeof(compressor));
/* ignore trailing newline */
sz = strlen(compressor);
if (sz > 0 && compressor[sz - 1] == '\n')
compressor[sz - 1] = 0x00;
if (!zcomp_available_algorithm(compressor))
return -EINVAL;
down_write(&zram->init_lock);
if (init_done(zram)) {
up_write(&zram->init_lock);
pr_info("Can't change algorithm for initialized device\n");
return -EBUSY;
}
strcpy(zram->compressor, compressor);
up_write(&zram->init_lock);
return len;
}
static ssize_t compact_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
down_read(&zram->init_lock);
if (!init_done(zram)) {
up_read(&zram->init_lock);
return -EINVAL;
}
zs_compact(zram->mem_pool);
up_read(&zram->init_lock);
return len;
}
static ssize_t io_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
ssize_t ret;
down_read(&zram->init_lock);
ret = scnprintf(buf, PAGE_SIZE,
"%8llu %8llu %8llu %8llu\n",
(u64)atomic64_read(&zram->stats.failed_reads),
(u64)atomic64_read(&zram->stats.failed_writes),
(u64)atomic64_read(&zram->stats.invalid_io),
(u64)atomic64_read(&zram->stats.notify_free));
up_read(&zram->init_lock);
return ret;
}
static ssize_t mm_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
struct zs_pool_stats pool_stats;
u64 orig_size, mem_used = 0;
long max_used;
ssize_t ret;
memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats));
down_read(&zram->init_lock);
if (init_done(zram)) {
mem_used = zs_get_total_pages(zram->mem_pool);
zs_pool_stats(zram->mem_pool, &pool_stats);
}
orig_size = atomic64_read(&zram->stats.pages_stored);
max_used = atomic_long_read(&zram->stats.max_used_pages);
ret = scnprintf(buf, PAGE_SIZE,
"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu\n",
orig_size << PAGE_SHIFT,
(u64)atomic64_read(&zram->stats.compr_data_size),
mem_used << PAGE_SHIFT,
zram->limit_pages << PAGE_SHIFT,
max_used << PAGE_SHIFT,
(u64)atomic64_read(&zram->stats.same_pages),
pool_stats.pages_compacted,
(u64)atomic64_read(&zram->stats.huge_pages));
up_read(&zram->init_lock);
return ret;
}
#ifdef CONFIG_ZRAM_WRITEBACK
#define FOUR_K(x) ((x) * (1 << (PAGE_SHIFT - 12)))
static ssize_t bd_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
ssize_t ret;
down_read(&zram->init_lock);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
ret = scnprintf(buf, PAGE_SIZE,
"%8llu %8llu %8llu %8llu %8llu %8llu %8llu %8llu %8llu "
"%8llu %8llu %8llu %8llu %8llu %8llu %8llu %8llu\n",
FOUR_K((u64)atomic64_read(&zram->stats.bd_expire)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_objcnt)),
(u64)(atomic64_read(&zram->stats.bd_size) >> PAGE_SHIFT),
FOUR_K((u64)atomic64_read(&zram->stats.bd_max_count)),
(u64)(atomic64_read(&zram->stats.bd_max_size) >> PAGE_SHIFT),
FOUR_K((u64)atomic64_read(&zram->stats.bd_ppr_count)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_ppr_reads)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_ppr_writes)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_ppr_objcnt)),
(u64)(atomic64_read(&zram->stats.bd_ppr_size) >> PAGE_SHIFT),
FOUR_K((u64)atomic64_read(&zram->stats.bd_ppr_max_count)),
(u64)(atomic64_read(&zram->stats.bd_ppr_max_size) >> PAGE_SHIFT),
FOUR_K((u64)atomic64_read(&zram->stats.bd_objreads)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_objwrites)));
#else
ret = scnprintf(buf, PAGE_SIZE,
"%8llu %8llu %8llu\n",
FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
#endif
up_read(&zram->init_lock);
return ret;
}
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
static ssize_t bd_stat_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
zram_reset_stats(zram);
return len;
}
#endif
#endif
static ssize_t debug_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int version = 1;
struct zram *zram = dev_to_zram(dev);
ssize_t ret;
down_read(&zram->init_lock);
ret = scnprintf(buf, PAGE_SIZE,
"version: %d\n%8llu %8llu\n",
version,
(u64)atomic64_read(&zram->stats.writestall),
(u64)atomic64_read(&zram->stats.miss_free));
up_read(&zram->init_lock);
return ret;
}
static DEVICE_ATTR_RO(io_stat);
static DEVICE_ATTR_RO(mm_stat);
#ifdef CONFIG_ZRAM_WRITEBACK
static DEVICE_ATTR_RW(bd_stat);
#endif
static DEVICE_ATTR_RO(debug_stat);
static void zram_meta_free(struct zram *zram, u64 disksize)
{
size_t num_pages = disksize >> PAGE_SHIFT;
size_t index;
/* Free all pages that are still in this zram device */
for (index = 0; index < num_pages; index++)
zram_free_page(zram, index);
zs_destroy_pool(zram->mem_pool);
vfree(zram->table);
}
static bool zram_meta_alloc(struct zram *zram, u64 disksize)
{
size_t num_pages;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
int i;
#endif
num_pages = disksize >> PAGE_SHIFT;
zram->table = vzalloc(array_size(num_pages, sizeof(*zram->table)));
if (!zram->table)
return false;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
for (i = 0; i < num_pages; i++)
INIT_LIST_HEAD(&zram->table[i].lru_list);
#endif
zram->mem_pool = zs_create_pool(zram->disk->disk_name);
if (!zram->mem_pool) {
vfree(zram->table);
return false;
}
if (!huge_class_size)
huge_class_size = zs_huge_class_size(zram->mem_pool);
return true;
}
/*
* To protect concurrent access to the same index entry,
* caller should hold this table index entry's bit_spinlock to
* indicate this index entry is accessing.
*/
static void zram_free_page(struct zram *zram, size_t index)
{
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
unsigned long flags;
#endif
unsigned long handle;
#ifdef CONFIG_ZRAM_MEMORY_TRACKING
zram->table[index].ac_time = 0;
#endif
if (zram_test_flag(zram, index, ZRAM_IDLE))
zram_clear_flag(zram, index, ZRAM_IDLE);
if (zram_test_flag(zram, index, ZRAM_HUGE)) {
zram_clear_flag(zram, index, ZRAM_HUGE);
atomic64_dec(&zram->stats.huge_pages);
}
if (zram_test_flag(zram, index, ZRAM_WB)) {
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
int size;
bool ppr = zram_test_flag(zram, index, ZRAM_PPR);
handle = zram_get_element(zram, index);
size = handle & (PAGE_SIZE - 1);
if (size == 0)
size = PAGE_SIZE;
atomic64_sub(size, &zram->stats.bd_size);
if (ppr) {
zram_clear_flag(zram, index, ZRAM_PPR);
atomic64_sub(size, &zram->stats.bd_ppr_size);
}
if (zram_test_flag(zram, index, ZRAM_EXPIRE)) {
zram_clear_flag(zram, index, ZRAM_EXPIRE);
atomic64_dec(&zram->stats.bd_expire);
}
zram_clear_flag(zram, index, ZRAM_WB);
free_block_bdev(zram, handle >> (PAGE_SHIFT * 2), ppr);
#else
zram_clear_flag(zram, index, ZRAM_WB);
free_block_bdev(zram, zram_get_element(zram, index) >> (PAGE_SHIFT * 2));
#endif
goto out;
}
/*
* No memory is allocated for same element filled pages.
* Simply clear same page flag.
*/
if (zram_test_flag(zram, index, ZRAM_SAME)) {
zram_clear_flag(zram, index, ZRAM_SAME);
atomic64_dec(&zram->stats.same_pages);
goto out;
}
handle = zram_get_handle(zram, index);
if (!handle)
return;
zs_free(zram->mem_pool, handle);
atomic64_sub(zram_get_obj_size(zram, index),
&zram->stats.compr_data_size);
out:
atomic64_dec(&zram->stats.pages_stored);
zram_set_handle(zram, index, 0);
zram_set_obj_size(zram, index, 0);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
if (zram_test_flag(zram, index, ZRAM_UNDER_PPR))
zram_clear_flag(zram, index, ZRAM_UNDER_PPR);
spin_lock_irqsave(&zram->list_lock, flags);
if (!list_empty(&zram->table[index].lru_list)) {
list_del_init(&zram->table[index].lru_list);
if (zram_test_flag(zram, index, ZRAM_LRU)) {
zram_clear_flag(zram, index, ZRAM_LRU);
atomic64_dec(&zram->stats.lru_pages);
}
}
spin_unlock_irqrestore(&zram->list_lock, flags);
#endif
WARN_ON_ONCE(zram->table[index].flags &
~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));
}
static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
struct bio *bio, bool partial_io)
{
int ret;
unsigned long handle;
unsigned int size;
void *src, *dst;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
unsigned long flags;
#endif
zram_slot_lock(zram, index);
if (zram_test_flag(zram, index, ZRAM_WB)) {
struct bio_vec bvec;
bvec.bv_page = page;
bvec.bv_len = PAGE_SIZE;
bvec.bv_offset = 0;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
atomic64_inc(&zram->stats.bd_objreads);
if (zram_test_flag(zram, index, ZRAM_PPR))
atomic64_inc(&zram->stats.bd_ppr_reads);
if (!zram_test_flag(zram, index, ZRAM_EXPIRE)) {
zram_set_flag(zram, index, ZRAM_EXPIRE);
atomic64_inc(&zram->stats.bd_expire);
}
if ((zram_get_element(zram, index) & (PAGE_SIZE - 1)) != 0) {
zram_set_flag(zram, index, ZRAM_READ_BDEV);
zram_slot_unlock(zram, index);
return read_comp_from_bdev(zram, &bvec,
zram_get_element(zram, index), bio);
}
#endif
zram_slot_unlock(zram, index);
return read_from_bdev(zram, &bvec,
zram_get_element(zram, index) >> (PAGE_SHIFT * 2),
bio, partial_io);
}
handle = zram_get_handle(zram, index);
if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) {
unsigned long value;
void *mem;
value = handle ? zram_get_element(zram, index) : 0;
mem = kmap_atomic(page);
zram_fill_page(mem, PAGE_SIZE, value);
kunmap_atomic(mem);
zram_slot_unlock(zram, index);
return 0;
}
size = zram_get_obj_size(zram, index);
src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
if (size == PAGE_SIZE) {
dst = kmap_atomic(page);
memcpy(dst, src, PAGE_SIZE);
kunmap_atomic(dst);
ret = 0;
} else {
struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
dst = kmap_atomic(page);
ret = zcomp_decompress(zstrm, src, size, dst);
/* Should NEVER happen. BUG() if it does. */
if (unlikely(ret)) {
#ifdef CONFIG_PGTABLE_MAPPING
unsigned long pa_start = 0, pa_end = 0;
if (is_vmalloc_addr(src)) {
void *src_last;
src_last = src + size - 1;
pa_start = (vmalloc_to_pfn(src) << PAGE_SHIFT);
pa_start |= (unsigned long)src & ~PAGE_MASK;
pa_end = vmalloc_to_pfn(src_last) << PAGE_SHIFT;
pa_end |= (unsigned long)src_last & ~PAGE_MASK;
pa_end += 1;
} else {
pa_start = virt_addr_valid(src) ? virt_to_phys(src) : 0;
pa_end = pa_start + size;
}
pr_err("%s Decompression failed! err=%d, page=%u, len=%u, vaddr=0x%px, paddr=0x%lx--0x%lx\n",
zram->compressor, ret, index, size, src, pa_start, pa_end);
#else
pr_err("%s Decompression failed! err=%d, page=%u, len=%u, vaddr=0x%px\n",
zram->compressor, ret, index, size, src);
#endif
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, src, size, 1);
BUG();
}
kunmap_atomic(dst);
zcomp_stream_put(zram->comp);
}
zs_unmap_object(zram->mem_pool, handle);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
if (zram_test_flag(zram, index, ZRAM_UNDER_PPR))
zram_clear_flag(zram, index, ZRAM_UNDER_PPR);
spin_lock_irqsave(&zram->list_lock, flags);
if (!list_empty(&zram->table[index].lru_list)) {
list_del_init(&zram->table[index].lru_list);
if (zram_test_flag(zram, index, ZRAM_LRU)) {
zram_clear_flag(zram, index, ZRAM_LRU);
atomic64_dec(&zram->stats.lru_pages);
}
}
spin_unlock_irqrestore(&zram->list_lock, flags);
#endif
zram_slot_unlock(zram, index);
return ret;
}
static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
u32 index, int offset, struct bio *bio)
{
int ret;
struct page *page;
page = bvec->bv_page;
if (is_partial_io(bvec)) {
/* Use a temporary buffer to decompress the page */
page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
if (!page)
return -ENOMEM;
}
ret = __zram_bvec_read(zram, page, index, bio, is_partial_io(bvec));
if (unlikely(ret))
goto out;
if (is_partial_io(bvec)) {
void *dst = kmap_atomic(bvec->bv_page);
void *src = kmap_atomic(page);
memcpy(dst + bvec->bv_offset, src + offset, bvec->bv_len);
kunmap_atomic(src);
kunmap_atomic(dst);
}
out:
if (is_partial_io(bvec))
__free_page(page);
return ret;
}
static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
u32 index, struct bio *bio)
{
int ret = 0;
unsigned long alloced_pages;
unsigned long handle = 0;
unsigned int comp_len = 0;
void *src, *dst, *mem;
struct zcomp_strm *zstrm;
struct page *page = bvec->bv_page;
unsigned long element = 0;
enum zram_pageflags flags = 0;
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
unsigned long irq_flags;
#endif
mem = kmap_atomic(page);
if (page_same_filled(mem, &element)) {
kunmap_atomic(mem);
/* Free memory associated with this sector now. */
flags = ZRAM_SAME;
atomic64_inc(&zram->stats.same_pages);
goto out;
}
kunmap_atomic(mem);
compress_again:
zstrm = zcomp_stream_get(zram->comp);
src = kmap_atomic(page);
ret = zcomp_compress(zstrm, src, &comp_len);
kunmap_atomic(src);
if (unlikely(ret)) {
zcomp_stream_put(zram->comp);
pr_err("Compression failed! err=%d\n", ret);
zs_free(zram->mem_pool, handle);
return ret;
}
if (comp_len >= huge_class_size)
comp_len = PAGE_SIZE;
/*
* handle allocation has 2 paths:
* a) fast path is executed with preemption disabled (for
* per-cpu streams) and has __GFP_DIRECT_RECLAIM bit clear,
* since we can't sleep;
* b) slow path enables preemption and attempts to allocate
* the page with __GFP_DIRECT_RECLAIM bit set. we have to
* put per-cpu compression stream and, thus, to re-do
* the compression once handle is allocated.
*
* if we have a 'non-null' handle here then we are coming
* from the slow path and handle has already been allocated.
*/
if (!handle)
handle = zs_malloc(zram->mem_pool, comp_len,
__GFP_KSWAPD_RECLAIM |
__GFP_NOWARN |
__GFP_HIGHMEM |
__GFP_MOVABLE |
__GFP_CMA);
if (!handle) {
zcomp_stream_put(zram->comp);
atomic64_inc(&zram->stats.writestall);
handle = zs_malloc(zram->mem_pool, comp_len,
GFP_NOIO | __GFP_HIGHMEM |
__GFP_MOVABLE | __GFP_CMA);
if (handle)
goto compress_again;
return -ENOMEM;
}
alloced_pages = zs_get_total_pages(zram->mem_pool);
zram_pool_total_size = alloced_pages << PAGE_SHIFT;
update_used_max(zram, alloced_pages);
if (zram->limit_pages && alloced_pages > zram->limit_pages) {
zcomp_stream_put(zram->comp);
zs_free(zram->mem_pool, handle);
return -ENOMEM;
}
dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);
src = zstrm->buffer;
if (comp_len == PAGE_SIZE)
src = kmap_atomic(page);
memcpy(dst, src, comp_len);
if (comp_len == PAGE_SIZE)
kunmap_atomic(src);
zcomp_stream_put(zram->comp);
zs_unmap_object(zram->mem_pool, handle);
atomic64_add(comp_len, &zram->stats.compr_data_size);
out:
/*
* Free memory associated with this sector
* before overwriting unused sectors.
*/
zram_slot_lock(zram, index);
zram_free_page(zram, index);
if (comp_len == PAGE_SIZE) {
zram_set_flag(zram, index, ZRAM_HUGE);
atomic64_inc(&zram->stats.huge_pages);
}
if (flags) {
zram_set_flag(zram, index, flags);
zram_set_element(zram, index, element);
} else {
zram_set_handle(zram, index, handle);
zram_set_obj_size(zram, index, comp_len);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
if (!page->mem_cgroup ||
page->mem_cgroup->swappiness != NON_LRU_SWAPPINESS) {
spin_lock_irqsave(&zram->list_lock, irq_flags);
list_add_tail(&zram->table[index].lru_list, &zram->list);
spin_unlock_irqrestore(&zram->list_lock, irq_flags);
zram_set_flag(zram, index, ZRAM_LRU);
atomic64_inc(&zram->stats.lru_pages);
}
#endif
}
zram_slot_unlock(zram, index);
/* Update stats */
atomic64_inc(&zram->stats.pages_stored);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
try_wakeup_zram_wbd(zram);
#endif
return ret;
}
static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
u32 index, int offset, struct bio *bio)
{
int ret;
struct page *page = NULL;
void *src;
struct bio_vec vec;
vec = *bvec;
if (is_partial_io(bvec)) {
void *dst;
/*
* This is a partial IO. We need to read the full page
* before to write the changes.
*/
page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
if (!page)
return -ENOMEM;
ret = __zram_bvec_read(zram, page, index, bio, true);
if (ret)
goto out;
src = kmap_atomic(bvec->bv_page);
dst = kmap_atomic(page);
memcpy(dst + offset, src + bvec->bv_offset, bvec->bv_len);
kunmap_atomic(dst);
kunmap_atomic(src);
vec.bv_page = page;
vec.bv_len = PAGE_SIZE;
vec.bv_offset = 0;
}
ret = __zram_bvec_write(zram, &vec, index, bio);
out:
if (is_partial_io(bvec))
__free_page(page);
return ret;
}
/*
* zram_bio_discard - handler on discard request
* @index: physical block index in PAGE_SIZE units
* @offset: byte offset within physical block
*/
static void zram_bio_discard(struct zram *zram, u32 index,
int offset, struct bio *bio)
{
size_t n = bio->bi_iter.bi_size;
/*
* zram manages data in physical block size units. Because logical block
* size isn't identical with physical block size on some arch, we
* could get a discard request pointing to a specific offset within a
* certain physical block. Although we can handle this request by
* reading that physiclal block and decompressing and partially zeroing
* and re-compressing and then re-storing it, this isn't reasonable
* because our intent with a discard request is to save memory. So
* skipping this logical block is appropriate here.
*/
if (offset) {
if (n <= (PAGE_SIZE - offset))
return;
n -= (PAGE_SIZE - offset);
index++;
}
while (n >= PAGE_SIZE) {
zram_slot_lock(zram, index);
zram_free_page(zram, index);
zram_slot_unlock(zram, index);
atomic64_inc(&zram->stats.notify_free);
index++;
n -= PAGE_SIZE;
}
}
/*
* Returns errno if it has some problem. Otherwise return 0 or 1.
* Returns 0 if IO request was done synchronously
* Returns 1 if IO request was successfully submitted.
*/
static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
int offset, unsigned int op, struct bio *bio)
{
unsigned long start_time = jiffies;
struct request_queue *q = zram->disk->queue;
int ret;
generic_start_io_acct(q, op, bvec->bv_len >> SECTOR_SHIFT,
&zram->disk->part0);
if (!op_is_write(op)) {
atomic64_inc(&zram->stats.num_reads);
ret = zram_bvec_read(zram, bvec, index, offset, bio);
flush_dcache_page(bvec->bv_page);
} else {
atomic64_inc(&zram->stats.num_writes);
ret = zram_bvec_write(zram, bvec, index, offset, bio);
}
generic_end_io_acct(q, op, &zram->disk->part0, start_time);
zram_slot_lock(zram, index);
zram_accessed(zram, index);
zram_slot_unlock(zram, index);
if (unlikely(ret < 0)) {
if (!op_is_write(op))
atomic64_inc(&zram->stats.failed_reads);
else
atomic64_inc(&zram->stats.failed_writes);
}
return ret;
}
static void __zram_make_request(struct zram *zram, struct bio *bio)
{
int offset;
u32 index;
struct bio_vec bvec;
struct bvec_iter iter;
index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
offset = (bio->bi_iter.bi_sector &
(SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
switch (bio_op(bio)) {
case REQ_OP_DISCARD:
case REQ_OP_WRITE_ZEROES:
zram_bio_discard(zram, index, offset, bio);
bio_endio(bio);
return;
default:
break;
}
bio_for_each_segment(bvec, bio, iter) {
struct bio_vec bv = bvec;
unsigned int unwritten = bvec.bv_len;
do {
bv.bv_len = min_t(unsigned int, PAGE_SIZE - offset,
unwritten);
if (zram_bvec_rw(zram, &bv, index, offset,
bio_op(bio), bio) < 0)
goto out;
bv.bv_offset += bv.bv_len;
unwritten -= bv.bv_len;
update_position(&index, &offset, &bv);
} while (unwritten);
}
bio_endio(bio);
return;
out:
bio_io_error(bio);
}
/*
* Handler function for all zram I/O requests.
*/
static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio)
{
struct zram *zram = queue->queuedata;
if (!valid_io_request(zram, bio->bi_iter.bi_sector,
bio->bi_iter.bi_size)) {
atomic64_inc(&zram->stats.invalid_io);
goto error;
}
__zram_make_request(zram, bio);
return BLK_QC_T_NONE;
error:
bio_io_error(bio);
return BLK_QC_T_NONE;
}
static void zram_slot_free_notify(struct block_device *bdev,
unsigned long index)
{
struct zram *zram;
zram = bdev->bd_disk->private_data;
atomic64_inc(&zram->stats.notify_free);
if (!zram_slot_trylock(zram, index)) {
atomic64_inc(&zram->stats.miss_free);
return;
}
zram_free_page(zram, index);
zram_slot_unlock(zram, index);
}
static int zram_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, unsigned int op)
{
int offset, ret;
u32 index;
struct zram *zram;
struct bio_vec bv;
if (PageTransHuge(page))
return -ENOTSUPP;
zram = bdev->bd_disk->private_data;
if (!valid_io_request(zram, sector, PAGE_SIZE)) {
atomic64_inc(&zram->stats.invalid_io);
ret = -EINVAL;
goto out;
}
index = sector >> SECTORS_PER_PAGE_SHIFT;
offset = (sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
bv.bv_page = page;
bv.bv_len = PAGE_SIZE;
bv.bv_offset = 0;
ret = zram_bvec_rw(zram, &bv, index, offset, op, NULL);
out:
/*
* If I/O fails, just return error(ie, non-zero) without
* calling page_endio.
* It causes resubmit the I/O with bio request by upper functions
* of rw_page(e.g., swap_readpage, __swap_writepage) and
* bio->bi_end_io does things to handle the error
* (e.g., SetPageError, set_page_dirty and extra works).
*/
if (unlikely(ret < 0))
return ret;
switch (ret) {
case 0:
page_endio(page, op_is_write(op), 0);
break;
case 1:
ret = 0;
break;
default:
WARN_ON(1);
}
return ret;
}
static void zram_reset_device(struct zram *zram)
{
struct zcomp *comp;
u64 disksize;
down_write(&zram->init_lock);
zram->limit_pages = 0;
if (!init_done(zram)) {
up_write(&zram->init_lock);
return;
}
comp = zram->comp;
disksize = zram->disksize;
zram->disksize = 0;
set_capacity(zram->disk, 0);
part_stat_set_all(&zram->disk->part0, 0);
up_write(&zram->init_lock);
/* I/O operation under all of CPU are done so let's free */
zram_meta_free(zram, disksize);
memset(&zram->stats, 0, sizeof(zram->stats));
zcomp_destroy(comp);
reset_bdev(zram);
}
static ssize_t disksize_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
u64 disksize;
struct zcomp *comp;
struct zram *zram = dev_to_zram(dev);
int err;
disksize = memparse(buf, NULL);
if (!disksize)
return -EINVAL;
down_write(&zram->init_lock);
if (init_done(zram)) {
pr_info("Cannot change disksize for initialized device\n");
err = -EBUSY;
goto out_unlock;
}
disksize = PAGE_ALIGN(disksize);
if (!zram_meta_alloc(zram, disksize)) {
err = -ENOMEM;
goto out_unlock;
}
comp = zcomp_create(zram->compressor);
if (IS_ERR(comp)) {
pr_err("Cannot initialise %s compressing backend\n",
zram->compressor);
err = PTR_ERR(comp);
goto out_free_meta;
}
zram->comp = comp;
zram->disksize = disksize;
set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
revalidate_disk(zram->disk);
up_write(&zram->init_lock);
return len;
out_free_meta:
zram_meta_free(zram, disksize);
out_unlock:
up_write(&zram->init_lock);
return err;
}
static ssize_t reset_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
unsigned short do_reset;
struct zram *zram;
struct block_device *bdev;
ret = kstrtou16(buf, 10, &do_reset);
if (ret)
return ret;
if (!do_reset)
return -EINVAL;
zram = dev_to_zram(dev);
bdev = bdget_disk(zram->disk, 0);
if (!bdev)
return -ENOMEM;
mutex_lock(&bdev->bd_mutex);
/* Do not reset an active device or claimed device */
if (bdev->bd_openers || zram->claim) {
mutex_unlock(&bdev->bd_mutex);
bdput(bdev);
return -EBUSY;
}
/* From now on, anyone can't open /dev/zram[0-9] */
zram->claim = true;
mutex_unlock(&bdev->bd_mutex);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
stop_lru_writeback(zram);
#endif
/* Make sure all the pending I/O are finished */
fsync_bdev(bdev);
zram_reset_device(zram);
revalidate_disk(zram->disk);
bdput(bdev);
mutex_lock(&bdev->bd_mutex);
zram->claim = false;
mutex_unlock(&bdev->bd_mutex);
return len;
}
static int zram_open(struct block_device *bdev, fmode_t mode)
{
int ret = 0;
struct zram *zram;
WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
zram = bdev->bd_disk->private_data;
/* zram was claimed to reset so open request fails */
if (zram->claim)
ret = -EBUSY;
return ret;
}
static const struct block_device_operations zram_devops = {
.open = zram_open,
.swap_slot_free_notify = zram_slot_free_notify,
.rw_page = zram_rw_page,
.owner = THIS_MODULE
};
static DEVICE_ATTR_WO(compact);
static DEVICE_ATTR_RW(disksize);
static DEVICE_ATTR_RO(initstate);
static DEVICE_ATTR_WO(reset);
static DEVICE_ATTR_WO(mem_limit);
static DEVICE_ATTR_WO(mem_used_max);
static DEVICE_ATTR_WO(idle);
static DEVICE_ATTR_RW(max_comp_streams);
static DEVICE_ATTR_RW(comp_algorithm);
#ifdef CONFIG_ZRAM_WRITEBACK
static DEVICE_ATTR_RW(backing_dev);
static DEVICE_ATTR_WO(writeback);
static DEVICE_ATTR_RW(writeback_limit);
static DEVICE_ATTR_RW(writeback_limit_enable);
#endif
static struct attribute *zram_disk_attrs[] = {
&dev_attr_disksize.attr,
&dev_attr_initstate.attr,
&dev_attr_reset.attr,
&dev_attr_compact.attr,
&dev_attr_mem_limit.attr,
&dev_attr_mem_used_max.attr,
&dev_attr_idle.attr,
&dev_attr_max_comp_streams.attr,
&dev_attr_comp_algorithm.attr,
#ifdef CONFIG_ZRAM_WRITEBACK
&dev_attr_backing_dev.attr,
&dev_attr_writeback.attr,
&dev_attr_writeback_limit.attr,
&dev_attr_writeback_limit_enable.attr,
#endif
&dev_attr_io_stat.attr,
&dev_attr_mm_stat.attr,
#ifdef CONFIG_ZRAM_WRITEBACK
&dev_attr_bd_stat.attr,
#endif
&dev_attr_debug_stat.attr,
NULL,
};
static const struct attribute_group zram_disk_attr_group = {
.attrs = zram_disk_attrs,
};
static const struct attribute_group *zram_disk_attr_groups[] = {
&zram_disk_attr_group,
NULL,
};
/*
* Allocate and initialize new zram device. the function returns
* '>= 0' device_id upon success, and negative value otherwise.
*/
static int zram_add(void)
{
struct zram *zram;
struct request_queue *queue;
int ret, device_id;
zram = kzalloc(sizeof(struct zram), GFP_KERNEL);
if (!zram)
return -ENOMEM;
ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL);
if (ret < 0)
goto out_free_dev;
device_id = ret;
init_rwsem(&zram->init_lock);
#ifdef CONFIG_ZRAM_WRITEBACK
spin_lock_init(&zram->wb_limit_lock);
#endif
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
INIT_LIST_HEAD(&zram->list);
spin_lock_init(&zram->list_lock);
spin_lock_init(&zram->wb_table_lock);
spin_lock_init(&zram->bitmap_lock);
mutex_init(&zram->blk_bitmap_lock);
#endif
queue = blk_alloc_queue(GFP_KERNEL);
if (!queue) {
pr_err("Error allocating disk queue for device %d\n",
device_id);
ret = -ENOMEM;
goto out_free_idr;
}
blk_queue_make_request(queue, zram_make_request);
/* gendisk structure */
zram->disk = alloc_disk(1);
if (!zram->disk) {
pr_err("Error allocating disk structure for device %d\n",
device_id);
ret = -ENOMEM;
goto out_free_queue;
}
zram->disk->major = zram_major;
zram->disk->first_minor = device_id;
zram->disk->fops = &zram_devops;
zram->disk->queue = queue;
zram->disk->queue->queuedata = zram;
zram->disk->private_data = zram;
snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
/* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
set_capacity(zram->disk, 0);
/* zram devices sort of resembles non-rotational disks */
blk_queue_flag_set(QUEUE_FLAG_NONROT, zram->disk->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue);
/*
* To ensure that we always get PAGE_SIZE aligned
* and n*PAGE_SIZED sized I/O requests.
*/
blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE);
blk_queue_logical_block_size(zram->disk->queue,
ZRAM_LOGICAL_BLOCK_SIZE);
blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
zram->disk->queue->limits.discard_granularity = PAGE_SIZE;
blk_queue_max_discard_sectors(zram->disk->queue, UINT_MAX);
blk_queue_flag_set(QUEUE_FLAG_DISCARD, zram->disk->queue);
/*
* zram_bio_discard() will clear all logical blocks if logical block
* size is identical with physical block size(PAGE_SIZE). But if it is
* different, we will skip discarding some parts of logical blocks in
* the part of the request range which isn't aligned to physical block
* size. So we can't ensure that all discarded logical blocks are
* zeroed.
*/
if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE)
blk_queue_max_write_zeroes_sectors(zram->disk->queue, UINT_MAX);
zram->disk->queue->backing_dev_info->capabilities |=
(BDI_CAP_STABLE_WRITES | BDI_CAP_SYNCHRONOUS_IO);
disk_to_dev(zram->disk)->groups = zram_disk_attr_groups;
add_disk(zram->disk);
strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
zram_debugfs_register(zram);
pr_info("Added device: %s\n", zram->disk->disk_name);
return device_id;
out_free_queue:
blk_cleanup_queue(queue);
out_free_idr:
idr_remove(&zram_index_idr, device_id);
out_free_dev:
kfree(zram);
return ret;
}
static int zram_remove(struct zram *zram)
{
struct block_device *bdev;
bdev = bdget_disk(zram->disk, 0);
if (!bdev)
return -ENOMEM;
mutex_lock(&bdev->bd_mutex);
if (bdev->bd_openers || zram->claim) {
mutex_unlock(&bdev->bd_mutex);
bdput(bdev);
return -EBUSY;
}
zram->claim = true;
mutex_unlock(&bdev->bd_mutex);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
stop_lru_writeback(zram);
#endif
zram_debugfs_unregister(zram);
/* Make sure all the pending I/O are finished */
fsync_bdev(bdev);
zram_reset_device(zram);
bdput(bdev);
pr_info("Removed device: %s\n", zram->disk->disk_name);
del_gendisk(zram->disk);
blk_cleanup_queue(zram->disk->queue);
put_disk(zram->disk);
kfree(zram);
return 0;
}
/* zram-control sysfs attributes */
/*
* NOTE: hot_add attribute is not the usual read-only sysfs attribute. In a
* sense that reading from this file does alter the state of your system -- it
* creates a new un-initialized zram device and returns back this device's
* device_id (or an error code if it fails to create a new device).
*/
static ssize_t hot_add_show(struct class *class,
struct class_attribute *attr,
char *buf)
{
int ret;
mutex_lock(&zram_index_mutex);
ret = zram_add();
mutex_unlock(&zram_index_mutex);
if (ret < 0)
return ret;
return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
}
static CLASS_ATTR_RO(hot_add);
static ssize_t hot_remove_store(struct class *class,
struct class_attribute *attr,
const char *buf,
size_t count)
{
struct zram *zram;
int ret, dev_id;
/* dev_id is gendisk->first_minor, which is `int' */
ret = kstrtoint(buf, 10, &dev_id);
if (ret)
return ret;
if (dev_id < 0)
return -EINVAL;
mutex_lock(&zram_index_mutex);
zram = idr_find(&zram_index_idr, dev_id);
if (zram) {
ret = zram_remove(zram);
if (!ret)
idr_remove(&zram_index_idr, dev_id);
} else {
ret = -ENODEV;
}
mutex_unlock(&zram_index_mutex);
return ret ? ret : count;
}
static CLASS_ATTR_WO(hot_remove);
static struct attribute *zram_control_class_attrs[] = {
&class_attr_hot_add.attr,
&class_attr_hot_remove.attr,
NULL,
};
ATTRIBUTE_GROUPS(zram_control_class);
static struct class zram_control_class = {
.name = "zram-control",
.owner = THIS_MODULE,
.class_groups = zram_control_class_groups,
};
static int zram_remove_cb(int id, void *ptr, void *data)
{
zram_remove(ptr);
return 0;
}
static void destroy_devices(void)
{
class_unregister(&zram_control_class);
idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);
zram_debugfs_destroy();
idr_destroy(&zram_index_idr);
unregister_blkdev(zram_major, "zram");
cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);
}
static int zram_size_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
struct seq_file *s;
s = (struct seq_file *)data;
if (s)
seq_printf(s, "ZramDevice: %8lu kB\n",
(unsigned long)zram_pool_total_size >> 10);
else
pr_cont("ZramDevice:%lukB ",
(unsigned long)zram_pool_total_size >> 10);
return 0;
}
static struct notifier_block zram_size_nb = {
.notifier_call = zram_size_notifier,
};
static int __init zram_init(void)
{
int ret;
ret = cpuhp_setup_state_multi(CPUHP_ZCOMP_PREPARE, "block/zram:prepare",
zcomp_cpu_up_prepare, zcomp_cpu_dead);
if (ret < 0)
return ret;
ret = class_register(&zram_control_class);
if (ret) {
pr_err("Unable to register zram-control class\n");
cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);
return ret;
}
zram_debugfs_create();
zram_major = register_blkdev(0, "zram");
if (zram_major <= 0) {
pr_err("Unable to get major number\n");
class_unregister(&zram_control_class);
cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);
return -EBUSY;
}
while (num_devices != 0) {
mutex_lock(&zram_index_mutex);
ret = zram_add();
mutex_unlock(&zram_index_mutex);
if (ret < 0)
goto out_error;
num_devices--;
}
show_mem_extra_notifier_register(&zram_size_nb);
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
am_app_launch_notifier_register(&zram_app_launch_nb);
#endif
return 0;
out_error:
destroy_devices();
return ret;
}
static void __exit zram_exit(void)
{
destroy_devices();
#ifdef CONFIG_ZRAM_LRU_WRITEBACK
am_app_launch_notifier_unregister(&zram_app_launch_nb);
#endif
}
module_init(zram_init);
module_exit(zram_exit);
module_param(num_devices, uint, 0);
MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
MODULE_DESCRIPTION("Compressed RAM Block Device");
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