286 lines
6.4 KiB
C
286 lines
6.4 KiB
C
/*
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* Copyright (c) 2016-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* This program is free software; you can redistribute it and/or modify it under
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* the terms of the GNU General Public License version 2 as published by the
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* Free Software Foundation. This program is dual-licensed; you may select
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* either version 2 of the GNU General Public License ("GPL") or BSD license
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* ("BSD").
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*/
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/* Compression level or 0 to disable */
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#define DO_ZLIB 9
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/* Compression level or 0 to disable */
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#define DO_ZSTD 0
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/* Buffer size */
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#define BUFFER_SIZE 4096
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/vmalloc.h>
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#include <linux/fs.h>
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#include <linux/uaccess.h>
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#if DO_ZSTD
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#include <linux/zstd.h>
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#endif
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#if DO_ZLIB
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#include <linux/zlib.h>
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#endif
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/* Device name to pass to register_chrdev(). */
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#define DEVICE_NAME "zstd_compress_test"
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/* Dynamically allocated device major number */
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static int device_major;
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/*
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* We reuse the same state, and thus can compress only one file at a time.
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*/
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static bool device_is_open;
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static void *workspace = NULL;
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/*
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* Input buffer used to put data coming from userspace.
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*/
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static uint8_t buffer_in[BUFFER_SIZE];
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static uint8_t buffer_out[BUFFER_SIZE];
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static uint64_t uncompressed_len;
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static uint64_t compressed_len;
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#if DO_ZSTD
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static ZSTD_CStream *state;
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static ZSTD_inBuffer input = {
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.src = buffer_in,
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.size = sizeof(buffer_in),
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.pos = sizeof(buffer_in),
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};
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static ZSTD_outBuffer output = {
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.dst = buffer_out,
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.size = sizeof(buffer_out),
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.pos = sizeof(buffer_out),
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};
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#endif /* DO_ZSTD */
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#if DO_ZLIB
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static z_stream state = {
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.next_in = buffer_in,
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.avail_in = 0,
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.total_in = 0,
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.next_out = buffer_out,
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.avail_out = sizeof(buffer_out),
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.total_out = 0,
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.msg = NULL,
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.state = NULL,
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.workspace = NULL,
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};
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#endif /* DO_ZLIB */
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static int zstd_compress_test_open(struct inode *i, struct file *f)
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{
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if (device_is_open)
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return -EBUSY;
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device_is_open = true;
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uncompressed_len = compressed_len = 0;
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#if DO_ZSTD
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if (ZSTD_isError(ZSTD_resetCStream(state, 0)))
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return -EIO;
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#endif
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#if DO_ZLIB
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if (zlib_deflateReset(&state) != Z_OK)
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return -EIO;
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#endif
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printk(KERN_INFO DEVICE_NAME ": opened\n");
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return 0;
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}
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static int zstd_compress_test_release(struct inode *i, struct file *f)
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{
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device_is_open = false;
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#if DO_ZSTD
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do {
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size_t ret;
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output.pos = 0;
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ret = ZSTD_endStream(state, &output);
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if (ZSTD_isError(ret)) {
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printk(KERN_INFO DEVICE_NAME ": zstd end error %u\n", ZSTD_getErrorCode(ret));
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return -EIO;
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}
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compressed_len += output.pos;
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} while (output.pos != output.size);
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#endif
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#if DO_ZLIB
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for (;;) {
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int ret;
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state.next_out = buffer_out;
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state.avail_out = sizeof(buffer_out);
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ret = zlib_deflate(&state, Z_FINISH);
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compressed_len += sizeof(buffer_out) - state.avail_out;
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if (ret == Z_STREAM_END)
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break;
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if (ret != Z_OK) {
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printk(KERN_INFO DEVICE_NAME ": zlib end error %d: %s\n", ret, state.msg);
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return -EIO;
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}
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}
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#endif
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printk(KERN_INFO DEVICE_NAME ": uncompressed_len = %llu\n", uncompressed_len);
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printk(KERN_INFO DEVICE_NAME ": compressed_len = %llu\n", compressed_len);
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printk(KERN_INFO DEVICE_NAME ": closed\n");
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return 0;
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}
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/*
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* Hash the data given to us from userspace.
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*/
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static ssize_t zstd_compress_test_write(struct file *file,
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const char __user *buf, size_t size, loff_t *pos)
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{
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size_t remaining = size;
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while (remaining > 0) {
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size_t const copy_size = min(remaining, sizeof(buffer_in));
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if (copy_from_user(buffer_in, buf, copy_size))
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return -EFAULT;
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buf += copy_size;
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remaining -= copy_size;
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uncompressed_len += copy_size;
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#if DO_ZSTD
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input.pos = 0;
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input.size = copy_size;
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while (input.pos != input.size) {
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size_t ret;
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output.pos = 0;
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ret = ZSTD_compressStream(state, &output, &input);
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if (ZSTD_isError(ret)) {
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printk(KERN_INFO DEVICE_NAME ": zstd compress error %u\n", ZSTD_getErrorCode(ret));
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return -EIO;
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}
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compressed_len += output.pos;
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}
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#endif
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#if DO_ZLIB
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state.next_in = buffer_in;
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state.avail_in = copy_size;
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while (state.avail_in > 0) {
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int ret;
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state.next_out = buffer_out;
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state.avail_out = sizeof(buffer_out);
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ret = zlib_deflate(&state, Z_NO_FLUSH);
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compressed_len += sizeof(buffer_out) - state.avail_out;
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if (ret != Z_OK) {
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printk(KERN_INFO DEVICE_NAME ": zlib end error %d: %s\n", ret, state.msg);
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return -EIO;
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}
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}
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#endif
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}
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return size;
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}
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/* register the character device. */
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static int __init zstd_compress_test_init(void)
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{
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static const struct file_operations fileops = {
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.owner = THIS_MODULE,
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.open = &zstd_compress_test_open,
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.release = &zstd_compress_test_release,
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.write = &zstd_compress_test_write
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};
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size_t workspace_size = 0;
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#if DO_ZSTD
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ZSTD_parameters params;
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#endif
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device_major = register_chrdev(0, DEVICE_NAME, &fileops);
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if (device_major < 0) {
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return device_major;
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}
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#if DO_ZSTD
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params = ZSTD_getParams(DO_ZSTD, 0, 0);
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workspace_size = ZSTD_CStreamWorkspaceBound(params.cParams);
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if (!(workspace = vmalloc(workspace_size)))
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goto fail;
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if (!(state = ZSTD_initCStream(params, 0, workspace, workspace_size)))
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goto fail;
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#endif
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#if DO_ZLIB
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workspace_size = zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL);
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if (!(workspace = vmalloc(workspace_size)))
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goto fail;
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state.workspace = workspace;
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if (zlib_deflateInit(&state, DO_ZLIB) != Z_OK)
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goto fail;
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#endif
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printk(KERN_INFO DEVICE_NAME ": module loaded\n");
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printk(KERN_INFO DEVICE_NAME ": compression requires %zu bytes of memory\n", workspace_size);
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printk(KERN_INFO DEVICE_NAME ": Create a device node with "
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"'mknod " DEVICE_NAME " c %d 0' and write data "
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"to it.\n", device_major);
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return 0;
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fail:
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printk(KERN_INFO DEVICE_NAME ": failed to load module\n");
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if (workspace) {
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vfree(workspace);
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workspace = NULL;
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}
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return -ENOMEM;
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}
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static void __exit zstd_compress_test_exit(void)
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{
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unregister_chrdev(device_major, DEVICE_NAME);
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#if DO_ZLIB
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zlib_deflateEnd(&state);
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#endif
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if (workspace) {
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vfree(workspace);
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workspace = NULL;
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}
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printk(KERN_INFO DEVICE_NAME ": module unloaded\n");
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}
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module_init(zstd_compress_test_init);
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module_exit(zstd_compress_test_exit);
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MODULE_DESCRIPTION("Zstd compression tester");
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MODULE_VERSION("1.0");
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MODULE_LICENSE("Dual BSD/GPL");
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