2170 lines
51 KiB
C
2170 lines
51 KiB
C
/*
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* Compressed RAM block device
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*
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* Copyright (C) 2008, 2009, 2010 Nitin Gupta
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* 2012, 2013 Minchan Kim
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*
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* This code is released using a dual license strategy: BSD/GPL
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* You can choose the licence that better fits your requirements.
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*
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* Released under the terms of 3-clause BSD License
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* Released under the terms of GNU General Public License Version 2.0
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*
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*/
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#define KMSG_COMPONENT "zram"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/bio.h>
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#include <linux/bitops.h>
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#include <linux/blkdev.h>
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#include <linux/buffer_head.h>
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#include <linux/device.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/backing-dev.h>
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#include <linux/string.h>
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#include <linux/vmalloc.h>
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#include <linux/err.h>
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#include <linux/idr.h>
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#include <linux/sysfs.h>
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#include <linux/debugfs.h>
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#include <linux/cpuhotplug.h>
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#include <linux/part_stat.h>
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#include "zram_drv.h"
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static DEFINE_IDR(zram_index_idr);
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/* idr index must be protected */
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static DEFINE_MUTEX(zram_index_mutex);
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static int zram_major;
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static const char *default_compressor = CONFIG_ZRAM_DEF_COMP;
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/* Module params (documentation at end) */
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static unsigned int num_devices = 1;
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/*
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* Pages that compress to sizes equals or greater than this are stored
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* uncompressed in memory.
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*/
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static size_t huge_class_size;
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static const struct block_device_operations zram_devops;
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static void zram_free_page(struct zram *zram, size_t index);
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static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
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u32 index, int offset, struct bio *bio);
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static int zram_slot_trylock(struct zram *zram, u32 index)
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{
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return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].flags);
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}
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static void zram_slot_lock(struct zram *zram, u32 index)
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{
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bit_spin_lock(ZRAM_LOCK, &zram->table[index].flags);
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}
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static void zram_slot_unlock(struct zram *zram, u32 index)
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{
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bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
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}
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static inline bool init_done(struct zram *zram)
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{
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return zram->disksize;
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}
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static inline struct zram *dev_to_zram(struct device *dev)
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{
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return (struct zram *)dev_to_disk(dev)->private_data;
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}
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static unsigned long zram_get_handle(struct zram *zram, u32 index)
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{
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return zram->table[index].handle;
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}
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static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle)
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{
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zram->table[index].handle = handle;
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}
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/* flag operations require table entry bit_spin_lock() being held */
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static bool zram_test_flag(struct zram *zram, u32 index,
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enum zram_pageflags flag)
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{
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return zram->table[index].flags & BIT(flag);
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}
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static void zram_set_flag(struct zram *zram, u32 index,
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enum zram_pageflags flag)
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{
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zram->table[index].flags |= BIT(flag);
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}
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static void zram_clear_flag(struct zram *zram, u32 index,
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enum zram_pageflags flag)
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{
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zram->table[index].flags &= ~BIT(flag);
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}
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static inline void zram_set_element(struct zram *zram, u32 index,
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unsigned long element)
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{
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zram->table[index].element = element;
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}
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static unsigned long zram_get_element(struct zram *zram, u32 index)
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{
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return zram->table[index].element;
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}
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static size_t zram_get_obj_size(struct zram *zram, u32 index)
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{
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return zram->table[index].flags & (BIT(ZRAM_FLAG_SHIFT) - 1);
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}
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static void zram_set_obj_size(struct zram *zram,
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u32 index, size_t size)
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{
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unsigned long flags = zram->table[index].flags >> ZRAM_FLAG_SHIFT;
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zram->table[index].flags = (flags << ZRAM_FLAG_SHIFT) | size;
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}
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static inline bool zram_allocated(struct zram *zram, u32 index)
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{
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return zram_get_obj_size(zram, index) ||
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zram_test_flag(zram, index, ZRAM_SAME) ||
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zram_test_flag(zram, index, ZRAM_WB);
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}
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#if PAGE_SIZE != 4096
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static inline bool is_partial_io(struct bio_vec *bvec)
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{
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return bvec->bv_len != PAGE_SIZE;
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}
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#else
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static inline bool is_partial_io(struct bio_vec *bvec)
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{
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return false;
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}
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#endif
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/*
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* Check if request is within bounds and aligned on zram logical blocks.
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*/
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static inline bool valid_io_request(struct zram *zram,
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sector_t start, unsigned int size)
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{
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u64 end, bound;
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/* unaligned request */
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if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
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return false;
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if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
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return false;
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end = start + (size >> SECTOR_SHIFT);
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bound = zram->disksize >> SECTOR_SHIFT;
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/* out of range range */
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if (unlikely(start >= bound || end > bound || start > end))
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return false;
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/* I/O request is valid */
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return true;
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}
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static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
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{
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*index += (*offset + bvec->bv_len) / PAGE_SIZE;
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*offset = (*offset + bvec->bv_len) % PAGE_SIZE;
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}
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static inline void update_used_max(struct zram *zram,
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const unsigned long pages)
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{
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unsigned long old_max, cur_max;
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old_max = atomic_long_read(&zram->stats.max_used_pages);
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do {
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cur_max = old_max;
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if (pages > cur_max)
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old_max = atomic_long_cmpxchg(
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&zram->stats.max_used_pages, cur_max, pages);
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} while (old_max != cur_max);
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}
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static inline void zram_fill_page(void *ptr, unsigned long len,
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unsigned long value)
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{
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WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long)));
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memset_l(ptr, value, len / sizeof(unsigned long));
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}
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static bool page_same_filled(void *ptr, unsigned long *element)
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{
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unsigned long *page;
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unsigned long val;
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unsigned int pos, last_pos = PAGE_SIZE / sizeof(*page) - 1;
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page = (unsigned long *)ptr;
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val = page[0];
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if (val != page[last_pos])
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return false;
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for (pos = 1; pos < last_pos; pos++) {
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if (val != page[pos])
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return false;
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}
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*element = val;
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return true;
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}
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static ssize_t initstate_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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u32 val;
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struct zram *zram = dev_to_zram(dev);
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down_read(&zram->init_lock);
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val = init_done(zram);
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up_read(&zram->init_lock);
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return scnprintf(buf, PAGE_SIZE, "%u\n", val);
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}
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static ssize_t disksize_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct zram *zram = dev_to_zram(dev);
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return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
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}
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static ssize_t mem_limit_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t len)
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{
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u64 limit;
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char *tmp;
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struct zram *zram = dev_to_zram(dev);
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limit = memparse(buf, &tmp);
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if (buf == tmp) /* no chars parsed, invalid input */
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return -EINVAL;
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down_write(&zram->init_lock);
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zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
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up_write(&zram->init_lock);
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return len;
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}
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static ssize_t mem_used_max_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t len)
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{
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int err;
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unsigned long val;
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struct zram *zram = dev_to_zram(dev);
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err = kstrtoul(buf, 10, &val);
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if (err || val != 0)
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return -EINVAL;
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down_read(&zram->init_lock);
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if (init_done(zram)) {
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atomic_long_set(&zram->stats.max_used_pages,
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zs_get_total_pages(zram->mem_pool));
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}
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up_read(&zram->init_lock);
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return len;
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}
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/*
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* Mark all pages which are older than or equal to cutoff as IDLE.
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* Callers should hold the zram init lock in read mode
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*/
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static void mark_idle(struct zram *zram, ktime_t cutoff)
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{
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int is_idle = 1;
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unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
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int index;
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for (index = 0; index < nr_pages; index++) {
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/*
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* Do not mark ZRAM_UNDER_WB slot as ZRAM_IDLE to close race.
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* See the comment in writeback_store.
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*/
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zram_slot_lock(zram, index);
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if (zram_allocated(zram, index) &&
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!zram_test_flag(zram, index, ZRAM_UNDER_WB)) {
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#ifdef CONFIG_ZRAM_MEMORY_TRACKING
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is_idle = !cutoff || ktime_after(cutoff, zram->table[index].ac_time);
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#endif
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if (is_idle)
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zram_set_flag(zram, index, ZRAM_IDLE);
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}
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zram_slot_unlock(zram, index);
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}
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}
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static ssize_t idle_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t len)
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{
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struct zram *zram = dev_to_zram(dev);
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ktime_t cutoff_time = 0;
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ssize_t rv = -EINVAL;
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if (!sysfs_streq(buf, "all")) {
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/*
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* If it did not parse as 'all' try to treat it as an integer
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* when we have memory tracking enabled.
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*/
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u64 age_sec;
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if (IS_ENABLED(CONFIG_ZRAM_MEMORY_TRACKING) && !kstrtoull(buf, 0, &age_sec))
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cutoff_time = ktime_sub(ktime_get_boottime(),
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ns_to_ktime(age_sec * NSEC_PER_SEC));
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else
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goto out;
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}
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down_read(&zram->init_lock);
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if (!init_done(zram))
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goto out_unlock;
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/*
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* A cutoff_time of 0 marks everything as idle, this is the
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* "all" behavior.
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*/
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mark_idle(zram, cutoff_time);
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rv = len;
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out_unlock:
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up_read(&zram->init_lock);
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out:
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return rv;
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}
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#ifdef CONFIG_ZRAM_WRITEBACK
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static ssize_t writeback_limit_enable_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t len)
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{
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struct zram *zram = dev_to_zram(dev);
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u64 val;
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ssize_t ret = -EINVAL;
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if (kstrtoull(buf, 10, &val))
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return ret;
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down_read(&zram->init_lock);
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spin_lock(&zram->wb_limit_lock);
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zram->wb_limit_enable = val;
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spin_unlock(&zram->wb_limit_lock);
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up_read(&zram->init_lock);
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ret = len;
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return ret;
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}
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static ssize_t writeback_limit_enable_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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bool val;
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struct zram *zram = dev_to_zram(dev);
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down_read(&zram->init_lock);
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spin_lock(&zram->wb_limit_lock);
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val = zram->wb_limit_enable;
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spin_unlock(&zram->wb_limit_lock);
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up_read(&zram->init_lock);
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return scnprintf(buf, PAGE_SIZE, "%d\n", val);
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}
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static ssize_t writeback_limit_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t len)
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{
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struct zram *zram = dev_to_zram(dev);
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u64 val;
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ssize_t ret = -EINVAL;
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if (kstrtoull(buf, 10, &val))
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return ret;
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down_read(&zram->init_lock);
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spin_lock(&zram->wb_limit_lock);
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zram->bd_wb_limit = val;
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spin_unlock(&zram->wb_limit_lock);
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up_read(&zram->init_lock);
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ret = len;
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return ret;
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}
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static ssize_t writeback_limit_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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u64 val;
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struct zram *zram = dev_to_zram(dev);
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down_read(&zram->init_lock);
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spin_lock(&zram->wb_limit_lock);
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val = zram->bd_wb_limit;
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spin_unlock(&zram->wb_limit_lock);
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up_read(&zram->init_lock);
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return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
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}
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static void reset_bdev(struct zram *zram)
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{
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struct block_device *bdev;
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if (!zram->backing_dev)
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return;
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bdev = zram->bdev;
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blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
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/* hope filp_close flush all of IO */
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filp_close(zram->backing_dev, NULL);
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zram->backing_dev = NULL;
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zram->bdev = NULL;
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zram->disk->fops = &zram_devops;
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kvfree(zram->bitmap);
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zram->bitmap = NULL;
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}
|
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static ssize_t backing_dev_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct file *file;
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struct zram *zram = dev_to_zram(dev);
|
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char *p;
|
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ssize_t ret;
|
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|
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down_read(&zram->init_lock);
|
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file = zram->backing_dev;
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if (!file) {
|
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memcpy(buf, "none\n", 5);
|
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up_read(&zram->init_lock);
|
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return 5;
|
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}
|
|
|
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p = file_path(file, buf, PAGE_SIZE - 1);
|
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if (IS_ERR(p)) {
|
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ret = PTR_ERR(p);
|
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goto out;
|
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}
|
|
|
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ret = strlen(p);
|
|
memmove(buf, p, ret);
|
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buf[ret++] = '\n';
|
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out:
|
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up_read(&zram->init_lock);
|
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return ret;
|
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}
|
|
|
|
static ssize_t backing_dev_store(struct device *dev,
|
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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;
|
|
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)
|
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return -ENOMEM;
|
|
|
|
down_write(&zram->init_lock);
|
|
if (init_done(zram)) {
|
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pr_info("Can't setup backing device for initialized device\n");
|
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err = -EBUSY;
|
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goto out;
|
|
}
|
|
|
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strscpy(file_name, buf, PATH_MAX);
|
|
/* ignore trailing newline */
|
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sz = strlen(file_name);
|
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if (sz > 0 && file_name[sz - 1] == '\n')
|
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file_name[sz - 1] = 0x00;
|
|
|
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backing_dev = filp_open(file_name, O_RDWR|O_LARGEFILE, 0);
|
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if (IS_ERR(backing_dev)) {
|
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err = PTR_ERR(backing_dev);
|
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backing_dev = NULL;
|
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goto out;
|
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}
|
|
|
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mapping = backing_dev->f_mapping;
|
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inode = mapping->host;
|
|
|
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/* Support only block device in this moment */
|
|
if (!S_ISBLK(inode->i_mode)) {
|
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err = -ENOTBLK;
|
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goto out;
|
|
}
|
|
|
|
bdev = blkdev_get_by_dev(inode->i_rdev,
|
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FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
|
|
if (IS_ERR(bdev)) {
|
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err = PTR_ERR(bdev);
|
|
bdev = NULL;
|
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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;
|
|
}
|
|
|
|
reset_bdev(zram);
|
|
|
|
zram->bdev = bdev;
|
|
zram->backing_dev = backing_dev;
|
|
zram->bitmap = bitmap;
|
|
zram->nr_pages = nr_pages;
|
|
up_write(&zram->init_lock);
|
|
|
|
pr_info("setup backing device %s\n", file_name);
|
|
kfree(file_name);
|
|
|
|
return len;
|
|
out:
|
|
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;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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(zram->bdev, 1, parent ? parent->bi_opf : REQ_OP_READ,
|
|
GFP_NOIO);
|
|
if (!bio)
|
|
return -ENOMEM;
|
|
|
|
bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
|
|
if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, bvec->bv_offset)) {
|
|
bio_put(bio);
|
|
return -EIO;
|
|
}
|
|
|
|
if (!parent)
|
|
bio->bi_end_io = zram_page_end_io;
|
|
else
|
|
bio_chain(bio, parent);
|
|
|
|
submit_bio(bio);
|
|
return 1;
|
|
}
|
|
|
|
#define PAGE_WB_SIG "page_index="
|
|
|
|
#define PAGE_WRITEBACK 0
|
|
#define HUGE_WRITEBACK (1<<0)
|
|
#define IDLE_WRITEBACK (1<<1)
|
|
|
|
|
|
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 = 0;
|
|
struct bio bio;
|
|
struct bio_vec bio_vec;
|
|
struct page *page;
|
|
ssize_t ret = len;
|
|
int mode, err;
|
|
unsigned long blk_idx = 0;
|
|
|
|
if (sysfs_streq(buf, "idle"))
|
|
mode = IDLE_WRITEBACK;
|
|
else if (sysfs_streq(buf, "huge"))
|
|
mode = HUGE_WRITEBACK;
|
|
else if (sysfs_streq(buf, "huge_idle"))
|
|
mode = IDLE_WRITEBACK | HUGE_WRITEBACK;
|
|
else {
|
|
if (strncmp(buf, PAGE_WB_SIG, sizeof(PAGE_WB_SIG) - 1))
|
|
return -EINVAL;
|
|
|
|
if (kstrtol(buf + sizeof(PAGE_WB_SIG) - 1, 10, &index) ||
|
|
index >= nr_pages)
|
|
return -EINVAL;
|
|
|
|
nr_pages = 1;
|
|
mode = PAGE_WRITEBACK;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
for (; nr_pages != 0; index++, nr_pages--) {
|
|
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, zram->bdev, &bio_vec, 1,
|
|
REQ_OP_WRITE | REQ_SYNC);
|
|
bio.bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
|
|
|
|
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.
|
|
*/
|
|
err = submit_bio_wait(&bio);
|
|
if (err) {
|
|
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);
|
|
/*
|
|
* Return last IO error unless every IO were
|
|
* not suceeded.
|
|
*/
|
|
ret = err;
|
|
continue;
|
|
}
|
|
|
|
atomic64_inc(&zram->stats.bd_writes);
|
|
/*
|
|
* 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);
|
|
blk_idx = 0;
|
|
atomic64_inc(&zram->stats.pages_stored);
|
|
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);
|
|
__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 ->submit_bio to be active at a time, so if we use
|
|
* chained IO with parent IO in same context, it's a deadlock. To avoid that,
|
|
* use a 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);
|
|
if (sync)
|
|
return read_from_bdev_sync(zram, bvec, entry, parent);
|
|
else
|
|
return read_from_bdev_async(zram, bvec, entry, parent);
|
|
}
|
|
#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;
|
|
|
|
strscpy(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 %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),
|
|
atomic_long_read(&pool_stats.pages_compacted),
|
|
(u64)atomic64_read(&zram->stats.huge_pages),
|
|
(u64)atomic64_read(&zram->stats.huge_pages_since));
|
|
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);
|
|
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)));
|
|
up_read(&zram->init_lock);
|
|
|
|
return ret;
|
|
}
|
|
#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_RO(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;
|
|
|
|
num_pages = disksize >> PAGE_SHIFT;
|
|
zram->table = vzalloc(array_size(num_pages, sizeof(*zram->table)));
|
|
if (!zram->table)
|
|
return false;
|
|
|
|
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)
|
|
{
|
|
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)) {
|
|
zram_clear_flag(zram, index, ZRAM_WB);
|
|
free_block_bdev(zram, zram_get_element(zram, index));
|
|
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);
|
|
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)
|
|
{
|
|
struct zcomp_strm *zstrm;
|
|
unsigned long handle;
|
|
unsigned int size;
|
|
void *src, *dst;
|
|
int ret;
|
|
|
|
zram_slot_lock(zram, index);
|
|
if (zram_test_flag(zram, index, ZRAM_WB)) {
|
|
struct bio_vec bvec;
|
|
|
|
zram_slot_unlock(zram, index);
|
|
/* A null bio means rw_page was used, we must fallback to bio */
|
|
if (!bio)
|
|
return -EOPNOTSUPP;
|
|
|
|
bvec.bv_page = page;
|
|
bvec.bv_len = PAGE_SIZE;
|
|
bvec.bv_offset = 0;
|
|
return read_from_bdev(zram, &bvec,
|
|
zram_get_element(zram, index),
|
|
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);
|
|
|
|
if (size != PAGE_SIZE)
|
|
zstrm = zcomp_stream_get(zram->comp);
|
|
|
|
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 {
|
|
dst = kmap_atomic(page);
|
|
ret = zcomp_decompress(zstrm, src, size, dst);
|
|
kunmap_atomic(dst);
|
|
zcomp_stream_put(zram->comp);
|
|
}
|
|
zs_unmap_object(zram->mem_pool, handle);
|
|
zram_slot_unlock(zram, index);
|
|
|
|
/* Should NEVER happen. Return bio error if it does. */
|
|
if (WARN_ON(ret))
|
|
pr_err("Decompression failed! err=%d, page=%u\n", ret, 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 *src = kmap_atomic(page);
|
|
|
|
memcpy_to_bvec(bvec, src + offset);
|
|
kunmap_atomic(src);
|
|
}
|
|
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 = -ENOMEM;
|
|
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;
|
|
|
|
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 (IS_ERR((void *)handle))
|
|
handle = zs_malloc(zram->mem_pool, comp_len,
|
|
__GFP_KSWAPD_RECLAIM |
|
|
__GFP_NOWARN |
|
|
__GFP_HIGHMEM |
|
|
__GFP_MOVABLE);
|
|
if (IS_ERR((void *)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);
|
|
if (IS_ERR((void *)handle))
|
|
return PTR_ERR((void *)handle);
|
|
|
|
if (comp_len != PAGE_SIZE)
|
|
goto compress_again;
|
|
/*
|
|
* If the page is not compressible, you need to acquire the
|
|
* lock and execute the code below. The zcomp_stream_get()
|
|
* call is needed to disable the cpu hotplug and grab the
|
|
* zstrm buffer back. It is necessary that the dereferencing
|
|
* of the zstrm variable below occurs correctly.
|
|
*/
|
|
zstrm = zcomp_stream_get(zram->comp);
|
|
}
|
|
|
|
alloced_pages = zs_get_total_pages(zram->mem_pool);
|
|
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);
|
|
atomic64_inc(&zram->stats.huge_pages_since);
|
|
}
|
|
|
|
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);
|
|
}
|
|
zram_slot_unlock(zram, index);
|
|
|
|
/* Update stats */
|
|
atomic64_inc(&zram->stats.pages_stored);
|
|
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;
|
|
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;
|
|
|
|
dst = kmap_atomic(page);
|
|
memcpy_from_bvec(dst + offset, bvec);
|
|
kunmap_atomic(dst);
|
|
|
|
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, enum req_op op, struct bio *bio)
|
|
{
|
|
int ret;
|
|
|
|
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);
|
|
}
|
|
|
|
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;
|
|
unsigned long start_time;
|
|
|
|
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;
|
|
}
|
|
|
|
start_time = bio_start_io_acct(bio);
|
|
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) {
|
|
bio->bi_status = BLK_STS_IOERR;
|
|
break;
|
|
}
|
|
|
|
bv.bv_offset += bv.bv_len;
|
|
unwritten -= bv.bv_len;
|
|
|
|
update_position(&index, &offset, &bv);
|
|
} while (unwritten);
|
|
}
|
|
bio_end_io_acct(bio, start_time);
|
|
bio_endio(bio);
|
|
}
|
|
|
|
/*
|
|
* Handler function for all zram I/O requests.
|
|
*/
|
|
static void zram_submit_bio(struct bio *bio)
|
|
{
|
|
struct zram *zram = bio->bi_bdev->bd_disk->private_data;
|
|
|
|
if (!valid_io_request(zram, bio->bi_iter.bi_sector,
|
|
bio->bi_iter.bi_size)) {
|
|
atomic64_inc(&zram->stats.invalid_io);
|
|
bio_io_error(bio);
|
|
return;
|
|
}
|
|
|
|
__zram_make_request(zram, bio);
|
|
}
|
|
|
|
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, enum req_op op)
|
|
{
|
|
int offset, ret;
|
|
u32 index;
|
|
struct zram *zram;
|
|
struct bio_vec bv;
|
|
unsigned long start_time;
|
|
|
|
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;
|
|
|
|
start_time = bdev_start_io_acct(bdev->bd_disk->part0,
|
|
SECTORS_PER_PAGE, op, jiffies);
|
|
ret = zram_bvec_rw(zram, &bv, index, offset, op, NULL);
|
|
bdev_end_io_acct(bdev->bd_disk->part0, op, start_time);
|
|
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)
|
|
{
|
|
down_write(&zram->init_lock);
|
|
|
|
zram->limit_pages = 0;
|
|
|
|
if (!init_done(zram)) {
|
|
up_write(&zram->init_lock);
|
|
return;
|
|
}
|
|
|
|
set_capacity_and_notify(zram->disk, 0);
|
|
part_stat_set_all(zram->disk->part0, 0);
|
|
|
|
/* I/O operation under all of CPU are done so let's free */
|
|
zram_meta_free(zram, zram->disksize);
|
|
zram->disksize = 0;
|
|
memset(&zram->stats, 0, sizeof(zram->stats));
|
|
zcomp_destroy(zram->comp);
|
|
zram->comp = NULL;
|
|
reset_bdev(zram);
|
|
|
|
up_write(&zram->init_lock);
|
|
}
|
|
|
|
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_and_notify(zram->disk, zram->disksize >> SECTOR_SHIFT);
|
|
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 gendisk *disk;
|
|
|
|
ret = kstrtou16(buf, 10, &do_reset);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (!do_reset)
|
|
return -EINVAL;
|
|
|
|
zram = dev_to_zram(dev);
|
|
disk = zram->disk;
|
|
|
|
mutex_lock(&disk->open_mutex);
|
|
/* Do not reset an active device or claimed device */
|
|
if (disk_openers(disk) || zram->claim) {
|
|
mutex_unlock(&disk->open_mutex);
|
|
return -EBUSY;
|
|
}
|
|
|
|
/* From now on, anyone can't open /dev/zram[0-9] */
|
|
zram->claim = true;
|
|
mutex_unlock(&disk->open_mutex);
|
|
|
|
/* Make sure all the pending I/O are finished */
|
|
sync_blockdev(disk->part0);
|
|
zram_reset_device(zram);
|
|
|
|
mutex_lock(&disk->open_mutex);
|
|
zram->claim = false;
|
|
mutex_unlock(&disk->open_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_disk->open_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,
|
|
.submit_bio = zram_submit_bio,
|
|
.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,
|
|
};
|
|
|
|
ATTRIBUTE_GROUPS(zram_disk);
|
|
|
|
/*
|
|
* 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;
|
|
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
|
|
|
|
/* gendisk structure */
|
|
zram->disk = blk_alloc_disk(NUMA_NO_NODE);
|
|
if (!zram->disk) {
|
|
pr_err("Error allocating disk structure for device %d\n",
|
|
device_id);
|
|
ret = -ENOMEM;
|
|
goto out_free_idr;
|
|
}
|
|
|
|
zram->disk->major = zram_major;
|
|
zram->disk->first_minor = device_id;
|
|
zram->disk->minors = 1;
|
|
zram->disk->flags |= GENHD_FL_NO_PART;
|
|
zram->disk->fops = &zram_devops;
|
|
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);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, zram->disk->queue);
|
|
ret = device_add_disk(NULL, zram->disk, zram_disk_groups);
|
|
if (ret)
|
|
goto out_cleanup_disk;
|
|
|
|
strscpy(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_cleanup_disk:
|
|
put_disk(zram->disk);
|
|
out_free_idr:
|
|
idr_remove(&zram_index_idr, device_id);
|
|
out_free_dev:
|
|
kfree(zram);
|
|
return ret;
|
|
}
|
|
|
|
static int zram_remove(struct zram *zram)
|
|
{
|
|
bool claimed;
|
|
|
|
mutex_lock(&zram->disk->open_mutex);
|
|
if (disk_openers(zram->disk)) {
|
|
mutex_unlock(&zram->disk->open_mutex);
|
|
return -EBUSY;
|
|
}
|
|
|
|
claimed = zram->claim;
|
|
if (!claimed)
|
|
zram->claim = true;
|
|
mutex_unlock(&zram->disk->open_mutex);
|
|
|
|
zram_debugfs_unregister(zram);
|
|
|
|
if (claimed) {
|
|
/*
|
|
* If we were claimed by reset_store(), del_gendisk() will
|
|
* wait until reset_store() is done, so nothing need to do.
|
|
*/
|
|
;
|
|
} else {
|
|
/* Make sure all the pending I/O are finished */
|
|
sync_blockdev(zram->disk->part0);
|
|
zram_reset_device(zram);
|
|
}
|
|
|
|
pr_info("Removed device: %s\n", zram->disk->disk_name);
|
|
|
|
del_gendisk(zram->disk);
|
|
|
|
/* del_gendisk drains pending reset_store */
|
|
WARN_ON_ONCE(claimed && zram->claim);
|
|
|
|
/*
|
|
* disksize_store() may be called in between zram_reset_device()
|
|
* and del_gendisk(), so run the last reset to avoid leaking
|
|
* anything allocated with disksize_store()
|
|
*/
|
|
zram_reset_device(zram);
|
|
|
|
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 struct class_attribute class_attr_hot_add =
|
|
__ATTR(hot_add, 0400, hot_add_show, NULL);
|
|
|
|
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)
|
|
{
|
|
WARN_ON_ONCE(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 __init zram_init(void)
|
|
{
|
|
int ret;
|
|
|
|
BUILD_BUG_ON(__NR_ZRAM_PAGEFLAGS > BITS_PER_LONG);
|
|
|
|
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--;
|
|
}
|
|
|
|
return 0;
|
|
|
|
out_error:
|
|
destroy_devices();
|
|
return ret;
|
|
}
|
|
|
|
static void __exit zram_exit(void)
|
|
{
|
|
destroy_devices();
|
|
}
|
|
|
|
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");
|