cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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decompressor_multi_percpu.c (2295B)

      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#include <linux/local_lock.h>
     12
     13#include "squashfs_fs.h"
     14#include "squashfs_fs_sb.h"
     15#include "decompressor.h"
     16#include "squashfs.h"
     17
     18/*
     19 * This file implements multi-threaded decompression using percpu
     20 * variables, one thread per cpu core.
     21 */
     22
     23struct squashfs_stream {
     24	void			*stream;
     25	local_lock_t	lock;
     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		local_lock_init(&stream->lock);
     47	}
     48
     49	kfree(comp_opts);
     50	return (__force void *) percpu;
     51
     52out:
     53	for_each_possible_cpu(cpu) {
     54		stream = per_cpu_ptr(percpu, cpu);
     55		if (!IS_ERR_OR_NULL(stream->stream))
     56			msblk->decompressor->free(stream->stream);
     57	}
     58	free_percpu(percpu);
     59	return ERR_PTR(err);
     60}
     61
     62void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
     63{
     64	struct squashfs_stream __percpu *percpu =
     65			(struct squashfs_stream __percpu *) msblk->stream;
     66	struct squashfs_stream *stream;
     67	int cpu;
     68
     69	if (msblk->stream) {
     70		for_each_possible_cpu(cpu) {
     71			stream = per_cpu_ptr(percpu, cpu);
     72			msblk->decompressor->free(stream->stream);
     73		}
     74		free_percpu(percpu);
     75	}
     76}
     77
     78int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
     79	int offset, int length, struct squashfs_page_actor *output)
     80{
     81	struct squashfs_stream *stream;
     82	int res;
     83
     84	local_lock(&msblk->stream->lock);
     85	stream = this_cpu_ptr(msblk->stream);
     86
     87	res = msblk->decompressor->decompress(msblk, stream->stream, bio,
     88					      offset, length, output);
     89
     90	local_unlock(&msblk->stream->lock);
     91
     92	if (res < 0)
     93		ERROR("%s decompression failed, data probably corrupt\n",
     94			msblk->decompressor->name);
     95
     96	return res;
     97}
     98
     99int squashfs_max_decompressors(void)
    100{
    101	return num_possible_cpus();
    102}