fs/squashfs/decompressor_multi_percpu.c

   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/buffer_head.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 };
  25
  26 void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
  27                                                 void *comp_opts)
  28 {
  29         struct squashfs_stream *stream;
  30         struct squashfs_stream __percpu *percpu;
  31         int err, cpu;
  32
  33         percpu = alloc_percpu(struct squashfs_stream);
  34         if (percpu == NULL)
  35                 return ERR_PTR(-ENOMEM);
  36
  37         for_each_possible_cpu(cpu) {
  38                 stream = per_cpu_ptr(percpu, cpu);
  39                 stream->stream = msblk->decompressor->init(msblk, comp_opts);
  40                 if (IS_ERR(stream->stream)) {
  41                         err = PTR_ERR(stream->stream);
  42                         goto out;
  43                 }
  44         }
  45
  46         kfree(comp_opts);
  47         return (__force void *) percpu;
  48
  49 out:
  50         for_each_possible_cpu(cpu) {
  51                 stream = per_cpu_ptr(percpu, cpu);
  52                 if (!IS_ERR_OR_NULL(stream->stream))
  53                         msblk->decompressor->free(stream->stream);
  54         }
  55         free_percpu(percpu);
  56         return ERR_PTR(err);
  57 }
  58
  59 void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
  60 {
  61         struct squashfs_stream __percpu *percpu =
  62                         (struct squashfs_stream __percpu *) msblk->stream;
  63         struct squashfs_stream *stream;
  64         int cpu;
  65
  66         if (msblk->stream) {
  67                 for_each_possible_cpu(cpu) {
  68                         stream = per_cpu_ptr(percpu, cpu);
  69                         msblk->decompressor->free(stream->stream);
  70                 }
  71                 free_percpu(percpu);
  72         }
  73 }
  74
  75 int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
  76         int b, int offset, int length, struct squashfs_page_actor *output)
  77 {
  78         struct squashfs_stream __percpu *percpu =
  79                         (struct squashfs_stream __percpu *) msblk->stream;
  80         struct squashfs_stream *stream = get_cpu_ptr(percpu);
  81         int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
  82                 offset, length, output);
  83         put_cpu_ptr(stream);
  84
  85         if (res < 0)
  86                 ERROR("%s decompression failed, data probably corrupt\n",
  87                         msblk->decompressor->name);
  88
  89         return res;
  90 }
  91
  92 int squashfs_max_decompressors(void)
  93 {
  94         return num_possible_cpus();
  95 }