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![Colin Ian King](/assets/img/avatar_default.png)
There is a spelling mistake in a pr_err error message. Fix it. Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
271 lines
5.6 KiB
C
271 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright 2021 Google LLC.
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*/
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#include <linux/init.h>
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#include <linux/highmem.h>
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#include <linux/kobject.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/vmalloc.h>
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#include "module-internal.h"
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static int module_extend_max_pages(struct load_info *info, unsigned int extent)
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{
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struct page **new_pages;
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new_pages = kvmalloc_array(info->max_pages + extent,
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sizeof(info->pages), GFP_KERNEL);
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if (!new_pages)
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return -ENOMEM;
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memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages));
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kvfree(info->pages);
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info->pages = new_pages;
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info->max_pages += extent;
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return 0;
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}
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static struct page *module_get_next_page(struct load_info *info)
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{
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struct page *page;
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int error;
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if (info->max_pages == info->used_pages) {
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error = module_extend_max_pages(info, info->used_pages);
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if (error)
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return ERR_PTR(error);
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}
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page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
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if (!page)
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return ERR_PTR(-ENOMEM);
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info->pages[info->used_pages++] = page;
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return page;
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}
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#ifdef CONFIG_MODULE_COMPRESS_GZIP
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#include <linux/zlib.h>
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#define MODULE_COMPRESSION gzip
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#define MODULE_DECOMPRESS_FN module_gzip_decompress
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/*
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* Calculate length of the header which consists of signature, header
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* flags, time stamp and operating system ID (10 bytes total), plus
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* an optional filename.
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*/
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static size_t module_gzip_header_len(const u8 *buf, size_t size)
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{
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const u8 signature[] = { 0x1f, 0x8b, 0x08 };
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size_t len = 10;
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if (size < len || memcmp(buf, signature, sizeof(signature)))
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return 0;
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if (buf[3] & 0x08) {
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do {
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/*
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* If we can't find the end of the file name we must
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* be dealing with a corrupted file.
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*/
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if (len == size)
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return 0;
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} while (buf[len++] != '\0');
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}
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return len;
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}
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static ssize_t module_gzip_decompress(struct load_info *info,
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const void *buf, size_t size)
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{
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struct z_stream_s s = { 0 };
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size_t new_size = 0;
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size_t gzip_hdr_len;
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ssize_t retval;
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int rc;
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gzip_hdr_len = module_gzip_header_len(buf, size);
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if (!gzip_hdr_len) {
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pr_err("not a gzip compressed module\n");
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return -EINVAL;
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}
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s.next_in = buf + gzip_hdr_len;
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s.avail_in = size - gzip_hdr_len;
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s.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
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if (!s.workspace)
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return -ENOMEM;
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rc = zlib_inflateInit2(&s, -MAX_WBITS);
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if (rc != Z_OK) {
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pr_err("failed to initialize decompressor: %d\n", rc);
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retval = -EINVAL;
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goto out;
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}
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do {
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struct page *page = module_get_next_page(info);
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if (!page) {
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retval = -ENOMEM;
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goto out_inflate_end;
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}
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s.next_out = kmap(page);
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s.avail_out = PAGE_SIZE;
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rc = zlib_inflate(&s, 0);
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kunmap(page);
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new_size += PAGE_SIZE - s.avail_out;
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} while (rc == Z_OK);
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if (rc != Z_STREAM_END) {
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pr_err("decompression failed with status %d\n", rc);
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retval = -EINVAL;
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goto out_inflate_end;
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}
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retval = new_size;
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out_inflate_end:
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zlib_inflateEnd(&s);
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out:
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kfree(s.workspace);
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return retval;
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}
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#elif CONFIG_MODULE_COMPRESS_XZ
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#include <linux/xz.h>
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#define MODULE_COMPRESSION xz
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#define MODULE_DECOMPRESS_FN module_xz_decompress
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static ssize_t module_xz_decompress(struct load_info *info,
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const void *buf, size_t size)
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{
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static const u8 signature[] = { 0xfd, '7', 'z', 'X', 'Z', 0 };
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struct xz_dec *xz_dec;
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struct xz_buf xz_buf;
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enum xz_ret xz_ret;
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size_t new_size = 0;
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ssize_t retval;
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if (size < sizeof(signature) ||
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memcmp(buf, signature, sizeof(signature))) {
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pr_err("not an xz compressed module\n");
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return -EINVAL;
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}
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xz_dec = xz_dec_init(XZ_DYNALLOC, (u32)-1);
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if (!xz_dec)
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return -ENOMEM;
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xz_buf.in_size = size;
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xz_buf.in = buf;
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xz_buf.in_pos = 0;
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do {
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struct page *page = module_get_next_page(info);
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if (!page) {
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retval = -ENOMEM;
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goto out;
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}
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xz_buf.out = kmap(page);
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xz_buf.out_pos = 0;
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xz_buf.out_size = PAGE_SIZE;
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xz_ret = xz_dec_run(xz_dec, &xz_buf);
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kunmap(page);
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new_size += xz_buf.out_pos;
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} while (xz_buf.out_pos == PAGE_SIZE && xz_ret == XZ_OK);
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if (xz_ret != XZ_STREAM_END) {
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pr_err("decompression failed with status %d\n", xz_ret);
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retval = -EINVAL;
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goto out;
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}
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retval = new_size;
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out:
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xz_dec_end(xz_dec);
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return retval;
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}
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#else
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#error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS"
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#endif
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int module_decompress(struct load_info *info, const void *buf, size_t size)
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{
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unsigned int n_pages;
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ssize_t data_size;
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int error;
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/*
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* Start with number of pages twice as big as needed for
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* compressed data.
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*/
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n_pages = DIV_ROUND_UP(size, PAGE_SIZE) * 2;
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error = module_extend_max_pages(info, n_pages);
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data_size = MODULE_DECOMPRESS_FN(info, buf, size);
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if (data_size < 0) {
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error = data_size;
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goto err;
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}
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info->hdr = vmap(info->pages, info->used_pages, VM_MAP, PAGE_KERNEL);
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if (!info->hdr) {
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error = -ENOMEM;
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goto err;
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}
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info->len = data_size;
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return 0;
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err:
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module_decompress_cleanup(info);
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return error;
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}
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void module_decompress_cleanup(struct load_info *info)
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{
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int i;
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if (info->hdr)
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vunmap(info->hdr);
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for (i = 0; i < info->used_pages; i++)
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__free_page(info->pages[i]);
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kvfree(info->pages);
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info->pages = NULL;
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info->max_pages = info->used_pages = 0;
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}
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static ssize_t compression_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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return sysfs_emit(buf, "%s\n", __stringify(MODULE_COMPRESSION));
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}
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static struct kobj_attribute module_compression_attr = __ATTR_RO(compression);
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static int __init module_decompress_sysfs_init(void)
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{
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int error;
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error = sysfs_create_file(&module_kset->kobj,
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&module_compression_attr.attr);
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if (error)
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pr_warn("Failed to create 'compression' attribute");
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return 0;
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}
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late_initcall(module_decompress_sysfs_init);
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