292 lines
7.6 KiB
C
292 lines
7.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/xz.h>
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#include <linux/module.h>
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#include "compress.h"
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struct z_erofs_lzma {
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struct z_erofs_lzma *next;
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struct xz_dec_microlzma *state;
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struct xz_buf buf;
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u8 bounce[PAGE_SIZE];
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};
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/* considering the LZMA performance, no need to use a lockless list for now */
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static DEFINE_SPINLOCK(z_erofs_lzma_lock);
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static unsigned int z_erofs_lzma_max_dictsize;
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static unsigned int z_erofs_lzma_nstrms, z_erofs_lzma_avail_strms;
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static struct z_erofs_lzma *z_erofs_lzma_head;
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static DECLARE_WAIT_QUEUE_HEAD(z_erofs_lzma_wq);
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module_param_named(lzma_streams, z_erofs_lzma_nstrms, uint, 0444);
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void z_erofs_lzma_exit(void)
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{
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/* there should be no running fs instance */
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while (z_erofs_lzma_avail_strms) {
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struct z_erofs_lzma *strm;
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spin_lock(&z_erofs_lzma_lock);
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strm = z_erofs_lzma_head;
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if (!strm) {
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spin_unlock(&z_erofs_lzma_lock);
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DBG_BUGON(1);
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return;
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}
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z_erofs_lzma_head = NULL;
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spin_unlock(&z_erofs_lzma_lock);
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while (strm) {
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struct z_erofs_lzma *n = strm->next;
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if (strm->state)
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xz_dec_microlzma_end(strm->state);
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kfree(strm);
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--z_erofs_lzma_avail_strms;
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strm = n;
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}
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}
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}
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int __init z_erofs_lzma_init(void)
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{
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unsigned int i;
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/* by default, use # of possible CPUs instead */
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if (!z_erofs_lzma_nstrms)
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z_erofs_lzma_nstrms = num_possible_cpus();
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for (i = 0; i < z_erofs_lzma_nstrms; ++i) {
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struct z_erofs_lzma *strm = kzalloc(sizeof(*strm), GFP_KERNEL);
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if (!strm) {
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z_erofs_lzma_exit();
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return -ENOMEM;
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}
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spin_lock(&z_erofs_lzma_lock);
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strm->next = z_erofs_lzma_head;
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z_erofs_lzma_head = strm;
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spin_unlock(&z_erofs_lzma_lock);
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++z_erofs_lzma_avail_strms;
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}
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return 0;
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}
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int z_erofs_load_lzma_config(struct super_block *sb,
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struct erofs_super_block *dsb,
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struct z_erofs_lzma_cfgs *lzma, int size)
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{
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static DEFINE_MUTEX(lzma_resize_mutex);
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unsigned int dict_size, i;
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struct z_erofs_lzma *strm, *head = NULL;
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int err;
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if (!lzma || size < sizeof(struct z_erofs_lzma_cfgs)) {
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erofs_err(sb, "invalid lzma cfgs, size=%u", size);
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return -EINVAL;
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}
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if (lzma->format) {
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erofs_err(sb, "unidentified lzma format %x, please check kernel version",
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le16_to_cpu(lzma->format));
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return -EINVAL;
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}
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dict_size = le32_to_cpu(lzma->dict_size);
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if (dict_size > Z_EROFS_LZMA_MAX_DICT_SIZE || dict_size < 4096) {
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erofs_err(sb, "unsupported lzma dictionary size %u",
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dict_size);
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return -EINVAL;
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}
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erofs_info(sb, "EXPERIMENTAL MicroLZMA in use. Use at your own risk!");
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/* in case 2 z_erofs_load_lzma_config() race to avoid deadlock */
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mutex_lock(&lzma_resize_mutex);
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if (z_erofs_lzma_max_dictsize >= dict_size) {
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mutex_unlock(&lzma_resize_mutex);
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return 0;
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}
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/* 1. collect/isolate all streams for the following check */
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for (i = 0; i < z_erofs_lzma_avail_strms; ++i) {
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struct z_erofs_lzma *last;
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again:
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spin_lock(&z_erofs_lzma_lock);
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strm = z_erofs_lzma_head;
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if (!strm) {
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spin_unlock(&z_erofs_lzma_lock);
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wait_event(z_erofs_lzma_wq,
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READ_ONCE(z_erofs_lzma_head));
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goto again;
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}
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z_erofs_lzma_head = NULL;
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spin_unlock(&z_erofs_lzma_lock);
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for (last = strm; last->next; last = last->next)
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++i;
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last->next = head;
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head = strm;
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}
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err = 0;
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/* 2. walk each isolated stream and grow max dict_size if needed */
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for (strm = head; strm; strm = strm->next) {
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if (strm->state)
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xz_dec_microlzma_end(strm->state);
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strm->state = xz_dec_microlzma_alloc(XZ_PREALLOC, dict_size);
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if (!strm->state)
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err = -ENOMEM;
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}
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/* 3. push back all to the global list and update max dict_size */
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spin_lock(&z_erofs_lzma_lock);
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DBG_BUGON(z_erofs_lzma_head);
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z_erofs_lzma_head = head;
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spin_unlock(&z_erofs_lzma_lock);
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wake_up_all(&z_erofs_lzma_wq);
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z_erofs_lzma_max_dictsize = dict_size;
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mutex_unlock(&lzma_resize_mutex);
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return err;
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}
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int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
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struct page **pagepool)
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{
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const unsigned int nrpages_out =
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PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
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const unsigned int nrpages_in =
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PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
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unsigned int inlen, outlen, pageofs;
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struct z_erofs_lzma *strm;
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u8 *kin;
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bool bounced = false;
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int no, ni, j, err = 0;
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/* 1. get the exact LZMA compressed size */
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kin = kmap(*rq->in);
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err = z_erofs_fixup_insize(rq, kin + rq->pageofs_in,
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min_t(unsigned int, rq->inputsize,
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EROFS_BLKSIZ - rq->pageofs_in));
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if (err) {
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kunmap(*rq->in);
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return err;
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}
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/* 2. get an available lzma context */
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again:
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spin_lock(&z_erofs_lzma_lock);
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strm = z_erofs_lzma_head;
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if (!strm) {
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spin_unlock(&z_erofs_lzma_lock);
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wait_event(z_erofs_lzma_wq, READ_ONCE(z_erofs_lzma_head));
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goto again;
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}
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z_erofs_lzma_head = strm->next;
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spin_unlock(&z_erofs_lzma_lock);
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/* 3. multi-call decompress */
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inlen = rq->inputsize;
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outlen = rq->outputsize;
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xz_dec_microlzma_reset(strm->state, inlen, outlen,
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!rq->partial_decoding);
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pageofs = rq->pageofs_out;
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strm->buf.in = kin + rq->pageofs_in;
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strm->buf.in_pos = 0;
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strm->buf.in_size = min_t(u32, inlen, PAGE_SIZE - rq->pageofs_in);
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inlen -= strm->buf.in_size;
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strm->buf.out = NULL;
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strm->buf.out_pos = 0;
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strm->buf.out_size = 0;
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for (ni = 0, no = -1;;) {
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enum xz_ret xz_err;
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if (strm->buf.out_pos == strm->buf.out_size) {
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if (strm->buf.out) {
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kunmap(rq->out[no]);
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strm->buf.out = NULL;
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}
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if (++no >= nrpages_out || !outlen) {
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erofs_err(rq->sb, "decompressed buf out of bound");
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err = -EFSCORRUPTED;
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break;
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}
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strm->buf.out_pos = 0;
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strm->buf.out_size = min_t(u32, outlen,
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PAGE_SIZE - pageofs);
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outlen -= strm->buf.out_size;
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if (!rq->out[no] && rq->fillgaps) /* deduped */
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rq->out[no] = erofs_allocpage(pagepool,
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GFP_KERNEL | __GFP_NOFAIL);
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if (rq->out[no])
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strm->buf.out = kmap(rq->out[no]) + pageofs;
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pageofs = 0;
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} else if (strm->buf.in_pos == strm->buf.in_size) {
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kunmap(rq->in[ni]);
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if (++ni >= nrpages_in || !inlen) {
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erofs_err(rq->sb, "compressed buf out of bound");
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err = -EFSCORRUPTED;
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break;
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}
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strm->buf.in_pos = 0;
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strm->buf.in_size = min_t(u32, inlen, PAGE_SIZE);
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inlen -= strm->buf.in_size;
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kin = kmap(rq->in[ni]);
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strm->buf.in = kin;
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bounced = false;
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}
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/*
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* Handle overlapping: Use bounced buffer if the compressed
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* data is under processing; Otherwise, Use short-lived pages
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* from the on-stack pagepool where pages share with the same
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* request.
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*/
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if (!bounced && rq->out[no] == rq->in[ni]) {
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memcpy(strm->bounce, strm->buf.in, strm->buf.in_size);
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strm->buf.in = strm->bounce;
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bounced = true;
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}
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for (j = ni + 1; j < nrpages_in; ++j) {
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struct page *tmppage;
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if (rq->out[no] != rq->in[j])
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continue;
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DBG_BUGON(erofs_page_is_managed(EROFS_SB(rq->sb),
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rq->in[j]));
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tmppage = erofs_allocpage(pagepool,
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GFP_KERNEL | __GFP_NOFAIL);
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set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE);
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copy_highpage(tmppage, rq->in[j]);
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rq->in[j] = tmppage;
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}
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xz_err = xz_dec_microlzma_run(strm->state, &strm->buf);
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DBG_BUGON(strm->buf.out_pos > strm->buf.out_size);
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DBG_BUGON(strm->buf.in_pos > strm->buf.in_size);
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if (xz_err != XZ_OK) {
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if (xz_err == XZ_STREAM_END && !outlen)
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break;
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erofs_err(rq->sb, "failed to decompress %d in[%u] out[%u]",
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xz_err, rq->inputsize, rq->outputsize);
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err = -EFSCORRUPTED;
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break;
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}
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}
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if (no < nrpages_out && strm->buf.out)
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kunmap(rq->out[no]);
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if (ni < nrpages_in)
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kunmap(rq->in[ni]);
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/* 4. push back LZMA stream context to the global list */
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spin_lock(&z_erofs_lzma_lock);
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strm->next = z_erofs_lzma_head;
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z_erofs_lzma_head = strm;
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spin_unlock(&z_erofs_lzma_lock);
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wake_up(&z_erofs_lzma_wq);
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return err;
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}
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