// SPDX-License-Identifier: GPL-2.0-only /* * Swap block device support for MTDs * Turns an MTD device into a swap device with block wear leveling * * Copyright © 2007,2011 Nokia Corporation. All rights reserved. * * Authors: Jarkko Lavinen <[email protected]> * * Based on Richard Purdie's earlier implementation in 2007. Background * support and lock-less operation written by Adrian Hunter. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/mtd/mtd.h> #include <linux/mtd/blktrans.h> #include <linux/rbtree.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/blkdev.h> #include <linux/swap.h> #include <linux/debugfs.h> #include <linux/seq_file.h> #include <linux/device.h> #include <linux/math64.h> #define MTDSWAP_PREFIX … /* * The number of free eraseblocks when GC should stop */ #define CLEAN_BLOCK_THRESHOLD … /* * Number of free eraseblocks below which GC can also collect low frag * blocks. */ #define LOW_FRAG_GC_THRESHOLD … /* * Wear level cost amortization. We want to do wear leveling on the background * without disturbing gc too much. This is made by defining max GC frequency. * Frequency value 6 means 1/6 of the GC passes will pick an erase block based * on the biggest wear difference rather than the biggest dirtiness. * * The lower freq2 should be chosen so that it makes sure the maximum erase * difference will decrease even if a malicious application is deliberately * trying to make erase differences large. */ #define MAX_ERASE_DIFF … #define COLLECT_NONDIRTY_BASE … #define COLLECT_NONDIRTY_FREQ1 … #define COLLECT_NONDIRTY_FREQ2 … #define PAGE_UNDEF … #define BLOCK_UNDEF … #define BLOCK_ERROR … #define BLOCK_MAX … #define EBLOCK_BAD … #define EBLOCK_NOMAGIC … #define EBLOCK_BITFLIP … #define EBLOCK_FAILED … #define EBLOCK_READERR … #define EBLOCK_IDX_SHIFT … struct swap_eb { … }; #define MTDSWAP_ECNT_MIN(rbroot) … #define MTDSWAP_ECNT_MAX(rbroot) … struct mtdswap_tree { … }; enum { … }; struct mtdswap_dev { … }; struct mtdswap_oobdata { … } __packed; #define MTDSWAP_MAGIC_CLEAN … #define MTDSWAP_MAGIC_DIRTY … #define MTDSWAP_TYPE_CLEAN … #define MTDSWAP_TYPE_DIRTY … #define MTDSWAP_OOBSIZE … #define MTDSWAP_ERASE_RETRIES … #define MTDSWAP_IO_RETRIES … enum { … }; /* * In the worst case mtdswap_writesect() has allocated the last clean * page from the current block and is then pre-empted by the GC * thread. The thread can consume a full erase block when moving a * block. */ #define MIN_SPARE_EBLOCKS … #define MIN_ERASE_BLOCKS … #define TREE_ROOT(d, name) … #define TREE_EMPTY(d, name) … #define TREE_NONEMPTY(d, name) … #define TREE_COUNT(d, name) … #define MTDSWAP_MBD_TO_MTDSWAP(dev) … static char partitions[128] = …; module_param_string(…); MODULE_PARM_DESC(…) …; static unsigned int spare_eblocks = …; module_param(spare_eblocks, uint, 0444); MODULE_PARM_DESC(…) …; static bool header; /* false */ module_param(header, bool, 0444); MODULE_PARM_DESC(…) …; static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background); static loff_t mtdswap_eb_offset(struct mtdswap_dev *d, struct swap_eb *eb) { … } static void mtdswap_eb_detach(struct mtdswap_dev *d, struct swap_eb *eb) { … } static void __mtdswap_rb_add(struct rb_root *root, struct swap_eb *eb) { … } static void mtdswap_rb_add(struct mtdswap_dev *d, struct swap_eb *eb, int idx) { … } static struct rb_node *mtdswap_rb_index(struct rb_root *root, unsigned int idx) { … } static int mtdswap_handle_badblock(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int mtdswap_handle_write_error(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int mtdswap_read_oob(struct mtdswap_dev *d, loff_t from, struct mtd_oob_ops *ops) { … } static int mtdswap_read_markers(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int mtdswap_write_marker(struct mtdswap_dev *d, struct swap_eb *eb, u16 marker) { … } /* * Are there any erase blocks without MAGIC_CLEAN header, presumably * because power was cut off after erase but before header write? We * need to guestimate the erase count. */ static void mtdswap_check_counts(struct mtdswap_dev *d) { … } static void mtdswap_scan_eblks(struct mtdswap_dev *d) { … } /* * Place eblk into a tree corresponding to its number of active blocks * it contains. */ static void mtdswap_store_eb(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int mtdswap_erase_block(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int mtdswap_map_free_block(struct mtdswap_dev *d, unsigned int page, unsigned int *block) { … } static unsigned int mtdswap_free_page_cnt(struct mtdswap_dev *d) { … } static unsigned int mtdswap_enough_free_pages(struct mtdswap_dev *d) { … } static int mtdswap_write_block(struct mtdswap_dev *d, char *buf, unsigned int page, unsigned int *bp, int gc_context) { … } static int mtdswap_move_block(struct mtdswap_dev *d, unsigned int oldblock, unsigned int *newblock) { … } static int mtdswap_gc_eblock(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int __mtdswap_choose_gc_tree(struct mtdswap_dev *d) { … } static int mtdswap_wlfreq(unsigned int maxdiff) { … } static int mtdswap_choose_wl_tree(struct mtdswap_dev *d) { … } static int mtdswap_choose_gc_tree(struct mtdswap_dev *d, unsigned int background) { … } static struct swap_eb *mtdswap_pick_gc_eblk(struct mtdswap_dev *d, unsigned int background) { … } static unsigned int mtdswap_test_patt(unsigned int i) { … } static unsigned int mtdswap_eblk_passes(struct mtdswap_dev *d, struct swap_eb *eb) { … } static int mtdswap_gc(struct mtdswap_dev *d, unsigned int background) { … } static void mtdswap_background(struct mtd_blktrans_dev *dev) { … } static void mtdswap_cleanup(struct mtdswap_dev *d) { … } static int mtdswap_flush(struct mtd_blktrans_dev *dev) { … } static unsigned int mtdswap_badblocks(struct mtd_info *mtd, uint64_t size) { … } static int mtdswap_writesect(struct mtd_blktrans_dev *dev, unsigned long page, char *buf) { … } /* Provide a dummy swap header for the kernel */ static int mtdswap_auto_header(struct mtdswap_dev *d, char *buf) { … } static int mtdswap_readsect(struct mtd_blktrans_dev *dev, unsigned long page, char *buf) { … } static int mtdswap_discard(struct mtd_blktrans_dev *dev, unsigned long first, unsigned nr_pages) { … } static int mtdswap_show(struct seq_file *s, void *data) { … } DEFINE_SHOW_ATTRIBUTE(…); static int mtdswap_add_debugfs(struct mtdswap_dev *d) { … } static int mtdswap_init(struct mtdswap_dev *d, unsigned int eblocks, unsigned int spare_cnt) { … } static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) { … } static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev) { … } static struct mtd_blktrans_ops mtdswap_ops = …; module_mtd_blktrans(…); MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …;
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