LXR linux/fs/squashfs/decompressor_multi

   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
  24struct squashfs_stream {
  25        void            *stream;
  26};
  27
  28void *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
  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
  61void 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
  77int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
  78        int b, int offset, int length, struct squashfs_page_actor *output)
  79{
  80        struct squashfs_stream __percpu *percpu =
  81                        (struct squashfs_stream __percpu *) msblk->stream;
  82        struct squashfs_stream *stream = get_cpu_ptr(percpu);
  83        int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
  84                offset, length, output);
  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
  94int squashfs_max_decompressors(void)
  95{
  96        return num_possible_cpus();
  97}
  98