9508c6b90b
The decompressor interface and code was written from
the point of view of single-threaded operation. In doing
so it mixed a lot of single-threaded implementation specific
aspects into the decompressor code and elsewhere which makes it
difficult to seamlessly support multiple different decompressor
implementations.
This patch does the following:
1. It removes compressor_options parsing from the decompressor
init() function. This allows the decompressor init() function
to be dynamically called to instantiate multiple decompressors,
without the compressor options needing to be read and parsed each
time.
2. It moves threading and all sleeping operations out of the
decompressors. In doing so, it makes the decompressors
non-blocking wrappers which only deal with interfacing with
the decompressor implementation.
3. It splits decompressor.[ch] into decompressor generic functions
in decompressor.[ch], and moves the single threaded
decompressor implementation into decompressor_single.c.
The result of this patch is Squashfs should now be able to
support multiple decompressors by adding new decompressor_xxx.c
files with specialised implementations of the functions in
decompressor_single.c
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Reviewed-by: Minchan Kim <minchan@kernel.org>
130 lines
2.9 KiB
C
130 lines
2.9 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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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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void **buffer, struct buffer_head **bh, int b, int offset, int length,
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int srclength, int pages)
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{
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int zlib_err, zlib_init = 0;
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int k = 0, page = 0;
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z_stream *stream = strm;
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stream->avail_out = 0;
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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 && page < pages) {
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stream->next_out = buffer[page++];
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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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goto out;
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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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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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