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 22 struct squashfs_stream { 23 void *stream; 24 local_lock_t lock; 25 }; 26 27 static 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 51 out: 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 61 static 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 77 static 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 } 99 100 static int squashfs_max_decompressors(void) 101 { 102 return num_possible_cpus(); 103 } 104 105 const 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