projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| d208383d PL |
1 | /* |
| 2 | * Copyright (c) 2013 | |
| 3 | * Phillip Lougher <phillip@squashfs.org.uk> | |
| 4 | * | |
| 5 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
| 6 | * the COPYING file in the top-level directory. | |
| 7 | */ | |
| 8 | ||
| 9 | #include <linux/types.h> | |
| 10 | #include <linux/slab.h> | |
| 11 | #include <linux/percpu.h> | |
| 12 | #include <linux/buffer_head.h> | |
| 13 | ||
| 14 | #include "squashfs_fs.h" | |
| 15 | #include "squashfs_fs_sb.h" | |
| 16 | #include "decompressor.h" | |
| 17 | #include "squashfs.h" | |
| 18 | ||
| 19 | /* | |
| 20 | * This file implements multi-threaded decompression using percpu | |
| 21 | * variables, one thread per cpu core. | |
| 22 | */ | |
| 23 | ||
| 24 | struct squashfs_stream { | |
| 25 | void *stream; | |
| 26 | }; | |
| 27 | ||
| 28 | void *squashfs_decompressor_create(struct squashfs_sb_info *msblk, | |
| 29 | void *comp_opts) | |
| 30 | { | |
| 31 | struct squashfs_stream *stream; | |
| 32 | struct squashfs_stream __percpu *percpu; | |
| 33 | int err, cpu; | |
| 34 | ||
| 35 | percpu = alloc_percpu(struct squashfs_stream); | |
| 36 | if (percpu == NULL) | |
| 37 | return ERR_PTR(-ENOMEM); | |
| 38 | ||
| 39 | for_each_possible_cpu(cpu) { | |
| 40 | stream = per_cpu_ptr(percpu, cpu); | |
| 41 | stream->stream = msblk->decompressor->init(msblk, comp_opts); | |
| 42 | if (IS_ERR(stream->stream)) { | |
| 43 | err = PTR_ERR(stream->stream); | |
| 44 | goto out; | |
| 45 | } | |
| 46 | } | |
| 47 | ||
| 48 | kfree(comp_opts); | |
| 49 | return (__force void *) 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 | 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 | ||
| 846b730e PL |
77 | int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh, |
| 78 | int b, int offset, int length, struct squashfs_page_actor *output) | |
| d208383d PL |
79 | { |
| 80 | struct squashfs_stream __percpu *percpu = | |
| 81 | (struct squashfs_stream __percpu *) msblk->stream; | |
| 82 | struct squashfs_stream *stream = get_cpu_ptr(percpu); | |
| 846b730e PL |
83 | int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b, |
| 84 | offset, length, output); | |
| d208383d PL |
85 | put_cpu_ptr(stream); |
| 86 | ||
| 87 | if (res < 0) | |
| 88 | ERROR("%s decompression failed, data probably corrupt\n", | |
| 89 | msblk->decompressor->name); | |
| 90 | ||
| 91 | return res; | |
| 92 | } | |
| 93 | ||
| 94 | int squashfs_max_decompressors(void) | |
| 95 | { | |
| 96 | return num_possible_cpus(); | |
| 97 | } |