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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (c) 20134 * 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 percpu19 * 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 (void *)(__force unsigned long) 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 (void __percpu *)(unsigned long) 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 (void __percpu *)(unsigned long) 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};111