846b730e99
Further generalise the decompressors by adding a page handler abstraction. This adds helpers to allow the decompressors to access and process the output buffers in an implementation independant manner. This allows different types of output buffer to be passed to the decompressors, with the implementation specific aspects handled at decompression time, but without the knowledge being held in the decompressor wrapper code. This will allow the decompressors to handle Squashfs cache buffers, and page cache pages. This patch adds the abstraction and an implementation for the caches. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
135 lines
3.1 KiB
C
135 lines
3.1 KiB
C
/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* zlib_wrapper.c
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*/
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#include <linux/mutex.h>
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#include <linux/buffer_head.h>
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#include <linux/slab.h>
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#include <linux/zlib.h>
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#include <linux/vmalloc.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs.h"
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#include "decompressor.h"
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#include "page_actor.h"
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static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)
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{
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z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
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if (stream == NULL)
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goto failed;
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stream->workspace = vmalloc(zlib_inflate_workspacesize());
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if (stream->workspace == NULL)
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goto failed;
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return stream;
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failed:
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ERROR("Failed to allocate zlib workspace\n");
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kfree(stream);
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return ERR_PTR(-ENOMEM);
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}
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static void zlib_free(void *strm)
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{
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z_stream *stream = strm;
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if (stream)
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vfree(stream->workspace);
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kfree(stream);
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}
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static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
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struct buffer_head **bh, int b, int offset, int length,
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struct squashfs_page_actor *output)
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{
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int zlib_err, zlib_init = 0, k = 0;
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z_stream *stream = strm;
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stream->avail_out = PAGE_CACHE_SIZE;
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stream->next_out = squashfs_first_page(output);
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stream->avail_in = 0;
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do {
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if (stream->avail_in == 0 && k < b) {
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int avail = min(length, msblk->devblksize - offset);
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length -= avail;
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stream->next_in = bh[k]->b_data + offset;
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stream->avail_in = avail;
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offset = 0;
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}
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if (stream->avail_out == 0) {
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stream->next_out = squashfs_next_page(output);
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if (stream->next_out != NULL)
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stream->avail_out = PAGE_CACHE_SIZE;
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}
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if (!zlib_init) {
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zlib_err = zlib_inflateInit(stream);
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if (zlib_err != Z_OK) {
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squashfs_finish_page(output);
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goto out;
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}
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zlib_init = 1;
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}
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zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
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if (stream->avail_in == 0 && k < b)
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put_bh(bh[k++]);
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} while (zlib_err == Z_OK);
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squashfs_finish_page(output);
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if (zlib_err != Z_STREAM_END)
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goto out;
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zlib_err = zlib_inflateEnd(stream);
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if (zlib_err != Z_OK)
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goto out;
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if (k < b)
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goto out;
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return stream->total_out;
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out:
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for (; k < b; k++)
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put_bh(bh[k]);
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return -EIO;
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}
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const struct squashfs_decompressor squashfs_zlib_comp_ops = {
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.init = zlib_init,
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.free = zlib_free,
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.decompress = zlib_uncompress,
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.id = ZLIB_COMPRESSION,
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.name = "zlib",
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.supported = 1
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};
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