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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>
86 lines
1.8 KiB
C
86 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, struct buffer_head **bh,
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int b, int offset, int length, struct squashfs_page_actor *output)
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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, bh, b,
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offset, length, output);
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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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