| 1 | |
| 2 | |
| 3 | * Copyright (c) 2013
|
| 4 | * Phillip Lougher <[email protected]>
|
| 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 | };
|