1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2013
  4 * Phillip Lougher <phillip@squashfs.org.uk>
  5 */
  6
  7#include <linux/types.h>
  8#include <linux/slab.h>
  9#include <linux/percpu.h>
 10#include <linux/local_lock.h>
 11
 12#include "squashfs_fs.h"
 13#include "squashfs_fs_sb.h"
 14#include "decompressor.h"
 15#include "squashfs.h"
 16
 17/*
 18 * This file implements multi-threaded decompression using percpu
 19 * variables, one thread per cpu core.
 20 */
 21
 22struct squashfs_stream {
 23	void			*stream;
 24	local_lock_t	lock;
 25};
 26
 27static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
 28						void *comp_opts)
 29{
 30	struct squashfs_stream *stream;
 31	struct squashfs_stream __percpu *percpu;
 32	int err, cpu;
 33
 34	percpu = alloc_percpu(struct squashfs_stream);
 35	if (percpu == NULL)
 36		return ERR_PTR(-ENOMEM);
 37
 38	for_each_possible_cpu(cpu) {
 39		stream = per_cpu_ptr(percpu, cpu);
 40		stream->stream = msblk->decompressor->init(msblk, comp_opts);
 41		if (IS_ERR(stream->stream)) {
 42			err = PTR_ERR(stream->stream);
 43			goto out;
 44		}
 45		local_lock_init(&stream->lock);
 46	}
 47
 48	kfree(comp_opts);
 49	return (__force void *) percpu;
 50
 51out:
 52	for_each_possible_cpu(cpu) {
 53		stream = per_cpu_ptr(percpu, cpu);
 54		if (!IS_ERR_OR_NULL(stream->stream))
 55			msblk->decompressor->free(stream->stream);
 56	}
 57	free_percpu(percpu);
 58	return ERR_PTR(err);
 59}
 60
 61static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
 62{
 63	struct squashfs_stream __percpu *percpu =
 64			(struct squashfs_stream __percpu *) msblk->stream;
 65	struct squashfs_stream *stream;
 66	int cpu;
 67
 68	if (msblk->stream) {
 69		for_each_possible_cpu(cpu) {
 70			stream = per_cpu_ptr(percpu, cpu);
 71			msblk->decompressor->free(stream->stream);
 72		}
 73		free_percpu(percpu);
 74	}
 75}
 76
 77static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
 78	int offset, int length, struct squashfs_page_actor *output)
 79{
 80	struct squashfs_stream *stream;
 81	struct squashfs_stream __percpu *percpu =
 82			(struct squashfs_stream __percpu *) msblk->stream;
 83	int res;
 84
 85	local_lock(&percpu->lock);
 86	stream = this_cpu_ptr(percpu);
 87
 88	res = msblk->decompressor->decompress(msblk, stream->stream, bio,
 89					      offset, length, output);
 90
 91	local_unlock(&percpu->lock);
 92
 93	if (res < 0)
 94		ERROR("%s decompression failed, data probably corrupt\n",
 95			msblk->decompressor->name);
 96
 97	return res;
 98}
 99
100static int squashfs_max_decompressors(void)
101{
102	return num_possible_cpus();
103}
104
105const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu = {
106	.create = squashfs_decompressor_create,
107	.destroy = squashfs_decompressor_destroy,
108	.decompress = squashfs_decompress,
109	.max_decompressors = squashfs_max_decompressors,
110};