forked from Minki/linux
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>
87 lines
1.8 KiB
C
87 lines
1.8 KiB
C
/*
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* Copyright (c) 2013
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/buffer_head.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "decompressor.h"
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#include "squashfs.h"
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/*
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* This file implements single-threaded decompression in the
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* decompressor framework
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*/
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struct squashfs_stream {
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void *stream;
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struct mutex mutex;
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};
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void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
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void *comp_opts)
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{
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struct squashfs_stream *stream;
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int err = -ENOMEM;
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stream = kmalloc(sizeof(*stream), GFP_KERNEL);
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if (stream == NULL)
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goto out;
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stream->stream = msblk->decompressor->init(msblk, comp_opts);
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if (IS_ERR(stream->stream)) {
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err = PTR_ERR(stream->stream);
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goto out;
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}
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kfree(comp_opts);
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mutex_init(&stream->mutex);
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return stream;
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out:
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kfree(stream);
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return ERR_PTR(err);
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}
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void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
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{
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struct squashfs_stream *stream = msblk->stream;
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if (stream) {
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msblk->decompressor->free(stream->stream);
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kfree(stream);
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}
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}
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int squashfs_decompress(struct squashfs_sb_info *msblk,
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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 res;
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struct squashfs_stream *stream = msblk->stream;
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mutex_lock(&stream->mutex);
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res = msblk->decompressor->decompress(msblk, stream->stream, buffer,
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bh, b, offset, length, srclength, pages);
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mutex_unlock(&stream->mutex);
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if (res < 0)
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ERROR("%s decompression failed, data probably corrupt\n",
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msblk->decompressor->name);
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return res;
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}
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int squashfs_max_decompressors(void)
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{
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return 1;
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}
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