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418 lines
12 KiB
418 lines
12 KiB
/* |
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* JFFS2 -- Journalling Flash File System, Version 2. |
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* |
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* Copyright © 2001-2007 Red Hat, Inc. |
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* Copyright © 2004-2010 David Woodhouse <[email protected]> |
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* Copyright © 2004 Ferenc Havasi <[email protected]>, |
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* University of Szeged, Hungary |
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* |
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* Created by Arjan van de Ven <[email protected]> |
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* |
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* For licensing information, see the file 'LICENCE' in this directory. |
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* |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include "compr.h" |
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static DEFINE_SPINLOCK(jffs2_compressor_list_lock); |
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/* Available compressors are on this list */ |
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static LIST_HEAD(jffs2_compressor_list); |
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/* Actual compression mode */ |
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static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY; |
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/* Statistics for blocks stored without compression */ |
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static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0; |
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/* |
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* Return 1 to use this compression |
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*/ |
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static int jffs2_is_best_compression(struct jffs2_compressor *this, |
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struct jffs2_compressor *best, uint32_t size, uint32_t bestsize) |
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{ |
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switch (jffs2_compression_mode) { |
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case JFFS2_COMPR_MODE_SIZE: |
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if (bestsize > size) |
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return 1; |
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return 0; |
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case JFFS2_COMPR_MODE_FAVOURLZO: |
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if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size)) |
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return 1; |
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if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size)) |
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return 1; |
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if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100))) |
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return 1; |
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if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size) |
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return 1; |
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return 0; |
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} |
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/* Shouldn't happen */ |
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return 0; |
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} |
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/* |
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* jffs2_selected_compress: |
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* @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB). |
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* If 0, just take the first available compression mode. |
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* @data_in: Pointer to uncompressed data |
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* @cpage_out: Pointer to returned pointer to buffer for compressed data |
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* @datalen: On entry, holds the amount of data available for compression. |
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* On exit, expected to hold the amount of data actually compressed. |
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* @cdatalen: On entry, holds the amount of space available for compressed |
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* data. On exit, expected to hold the actual size of the compressed |
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* data. |
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* |
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* Returns: the compression type used. Zero is used to show that the data |
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* could not be compressed; probably because we couldn't find the requested |
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* compression mode. |
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*/ |
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static int jffs2_selected_compress(u8 compr, unsigned char *data_in, |
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unsigned char **cpage_out, u32 *datalen, u32 *cdatalen) |
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{ |
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struct jffs2_compressor *this; |
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int err, ret = JFFS2_COMPR_NONE; |
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uint32_t orig_slen, orig_dlen; |
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char *output_buf; |
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output_buf = kmalloc(*cdatalen, GFP_KERNEL); |
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if (!output_buf) { |
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pr_warn("No memory for compressor allocation. Compression failed.\n"); |
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return ret; |
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} |
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orig_slen = *datalen; |
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orig_dlen = *cdatalen; |
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spin_lock(&jffs2_compressor_list_lock); |
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list_for_each_entry(this, &jffs2_compressor_list, list) { |
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/* Skip decompress-only and disabled modules */ |
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if (!this->compress || this->disabled) |
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continue; |
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/* Skip if not the desired compression type */ |
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if (compr && (compr != this->compr)) |
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continue; |
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/* |
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* Either compression type was unspecified, or we found our |
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* compressor; either way, we're good to go. |
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*/ |
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this->usecount++; |
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spin_unlock(&jffs2_compressor_list_lock); |
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*datalen = orig_slen; |
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*cdatalen = orig_dlen; |
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err = this->compress(data_in, output_buf, datalen, cdatalen); |
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spin_lock(&jffs2_compressor_list_lock); |
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this->usecount--; |
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if (!err) { |
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/* Success */ |
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ret = this->compr; |
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this->stat_compr_blocks++; |
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this->stat_compr_orig_size += *datalen; |
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this->stat_compr_new_size += *cdatalen; |
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break; |
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} |
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} |
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spin_unlock(&jffs2_compressor_list_lock); |
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if (ret == JFFS2_COMPR_NONE) |
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kfree(output_buf); |
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else |
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*cpage_out = output_buf; |
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return ret; |
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} |
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/* jffs2_compress: |
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* @data_in: Pointer to uncompressed data |
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* @cpage_out: Pointer to returned pointer to buffer for compressed data |
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* @datalen: On entry, holds the amount of data available for compression. |
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* On exit, expected to hold the amount of data actually compressed. |
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* @cdatalen: On entry, holds the amount of space available for compressed |
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* data. On exit, expected to hold the actual size of the compressed |
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* data. |
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* |
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* Returns: Lower byte to be stored with data indicating compression type used. |
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* Zero is used to show that the data could not be compressed - the |
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* compressed version was actually larger than the original. |
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* Upper byte will be used later. (soon) |
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* |
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* If the cdata buffer isn't large enough to hold all the uncompressed data, |
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* jffs2_compress should compress as much as will fit, and should set |
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* *datalen accordingly to show the amount of data which were compressed. |
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*/ |
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uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
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unsigned char *data_in, unsigned char **cpage_out, |
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uint32_t *datalen, uint32_t *cdatalen) |
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{ |
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int ret = JFFS2_COMPR_NONE; |
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int mode, compr_ret; |
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struct jffs2_compressor *this, *best=NULL; |
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unsigned char *output_buf = NULL, *tmp_buf; |
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uint32_t orig_slen, orig_dlen; |
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uint32_t best_slen=0, best_dlen=0; |
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if (c->mount_opts.override_compr) |
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mode = c->mount_opts.compr; |
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else |
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mode = jffs2_compression_mode; |
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switch (mode) { |
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case JFFS2_COMPR_MODE_NONE: |
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break; |
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case JFFS2_COMPR_MODE_PRIORITY: |
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ret = jffs2_selected_compress(0, data_in, cpage_out, datalen, |
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cdatalen); |
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break; |
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case JFFS2_COMPR_MODE_SIZE: |
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case JFFS2_COMPR_MODE_FAVOURLZO: |
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orig_slen = *datalen; |
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orig_dlen = *cdatalen; |
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spin_lock(&jffs2_compressor_list_lock); |
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list_for_each_entry(this, &jffs2_compressor_list, list) { |
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/* Skip decompress-only backwards-compatibility and disabled modules */ |
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if ((!this->compress)||(this->disabled)) |
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continue; |
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/* Allocating memory for output buffer if necessary */ |
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if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) { |
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spin_unlock(&jffs2_compressor_list_lock); |
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kfree(this->compr_buf); |
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spin_lock(&jffs2_compressor_list_lock); |
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this->compr_buf_size=0; |
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this->compr_buf=NULL; |
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} |
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if (!this->compr_buf) { |
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spin_unlock(&jffs2_compressor_list_lock); |
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tmp_buf = kmalloc(orig_slen, GFP_KERNEL); |
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spin_lock(&jffs2_compressor_list_lock); |
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if (!tmp_buf) { |
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pr_warn("No memory for compressor allocation. (%d bytes)\n", |
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orig_slen); |
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continue; |
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} |
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else { |
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this->compr_buf = tmp_buf; |
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this->compr_buf_size = orig_slen; |
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} |
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} |
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this->usecount++; |
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spin_unlock(&jffs2_compressor_list_lock); |
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*datalen = orig_slen; |
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*cdatalen = orig_dlen; |
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compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen); |
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spin_lock(&jffs2_compressor_list_lock); |
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this->usecount--; |
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if (!compr_ret) { |
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if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen)) |
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&& (*cdatalen < *datalen)) { |
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best_dlen = *cdatalen; |
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best_slen = *datalen; |
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best = this; |
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} |
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} |
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} |
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if (best_dlen) { |
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*cdatalen = best_dlen; |
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*datalen = best_slen; |
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output_buf = best->compr_buf; |
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best->compr_buf = NULL; |
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best->compr_buf_size = 0; |
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best->stat_compr_blocks++; |
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best->stat_compr_orig_size += best_slen; |
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best->stat_compr_new_size += best_dlen; |
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ret = best->compr; |
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*cpage_out = output_buf; |
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} |
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spin_unlock(&jffs2_compressor_list_lock); |
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break; |
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case JFFS2_COMPR_MODE_FORCELZO: |
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ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in, |
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cpage_out, datalen, cdatalen); |
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break; |
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case JFFS2_COMPR_MODE_FORCEZLIB: |
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ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in, |
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cpage_out, datalen, cdatalen); |
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break; |
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default: |
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pr_err("unknown compression mode\n"); |
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} |
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if (ret == JFFS2_COMPR_NONE) { |
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*cpage_out = data_in; |
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*datalen = *cdatalen; |
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none_stat_compr_blocks++; |
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none_stat_compr_size += *datalen; |
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} |
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return ret; |
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} |
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int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
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uint16_t comprtype, unsigned char *cdata_in, |
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unsigned char *data_out, uint32_t cdatalen, uint32_t datalen) |
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{ |
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struct jffs2_compressor *this; |
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int ret; |
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/* Older code had a bug where it would write non-zero 'usercompr' |
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fields. Deal with it. */ |
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if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB) |
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comprtype &= 0xff; |
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switch (comprtype & 0xff) { |
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case JFFS2_COMPR_NONE: |
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/* This should be special-cased elsewhere, but we might as well deal with it */ |
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memcpy(data_out, cdata_in, datalen); |
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none_stat_decompr_blocks++; |
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break; |
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case JFFS2_COMPR_ZERO: |
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memset(data_out, 0, datalen); |
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break; |
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default: |
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spin_lock(&jffs2_compressor_list_lock); |
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list_for_each_entry(this, &jffs2_compressor_list, list) { |
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if (comprtype == this->compr) { |
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this->usecount++; |
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spin_unlock(&jffs2_compressor_list_lock); |
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ret = this->decompress(cdata_in, data_out, cdatalen, datalen); |
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spin_lock(&jffs2_compressor_list_lock); |
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if (ret) { |
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pr_warn("Decompressor \"%s\" returned %d\n", |
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this->name, ret); |
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} |
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else { |
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this->stat_decompr_blocks++; |
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} |
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this->usecount--; |
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spin_unlock(&jffs2_compressor_list_lock); |
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return ret; |
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} |
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} |
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pr_warn("compression type 0x%02x not available\n", comprtype); |
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spin_unlock(&jffs2_compressor_list_lock); |
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return -EIO; |
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} |
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return 0; |
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} |
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int jffs2_register_compressor(struct jffs2_compressor *comp) |
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{ |
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struct jffs2_compressor *this; |
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if (!comp->name) { |
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pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n"); |
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return -1; |
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} |
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comp->compr_buf_size=0; |
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comp->compr_buf=NULL; |
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comp->usecount=0; |
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comp->stat_compr_orig_size=0; |
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comp->stat_compr_new_size=0; |
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comp->stat_compr_blocks=0; |
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comp->stat_decompr_blocks=0; |
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jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name); |
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spin_lock(&jffs2_compressor_list_lock); |
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list_for_each_entry(this, &jffs2_compressor_list, list) { |
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if (this->priority < comp->priority) { |
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list_add(&comp->list, this->list.prev); |
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goto out; |
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} |
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} |
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list_add_tail(&comp->list, &jffs2_compressor_list); |
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out: |
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D2(list_for_each_entry(this, &jffs2_compressor_list, list) { |
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printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); |
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}) |
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spin_unlock(&jffs2_compressor_list_lock); |
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return 0; |
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} |
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int jffs2_unregister_compressor(struct jffs2_compressor *comp) |
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{ |
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D2(struct jffs2_compressor *this); |
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jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name); |
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spin_lock(&jffs2_compressor_list_lock); |
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if (comp->usecount) { |
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spin_unlock(&jffs2_compressor_list_lock); |
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pr_warn("Compressor module is in use. Unregister failed.\n"); |
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return -1; |
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} |
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list_del(&comp->list); |
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D2(list_for_each_entry(this, &jffs2_compressor_list, list) { |
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printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); |
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}) |
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spin_unlock(&jffs2_compressor_list_lock); |
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return 0; |
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} |
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void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig) |
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{ |
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if (orig != comprbuf) |
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kfree(comprbuf); |
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} |
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int __init jffs2_compressors_init(void) |
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{ |
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/* Registering compressors */ |
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#ifdef CONFIG_JFFS2_ZLIB |
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jffs2_zlib_init(); |
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#endif |
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#ifdef CONFIG_JFFS2_RTIME |
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jffs2_rtime_init(); |
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#endif |
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#ifdef CONFIG_JFFS2_RUBIN |
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jffs2_rubinmips_init(); |
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jffs2_dynrubin_init(); |
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#endif |
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#ifdef CONFIG_JFFS2_LZO |
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jffs2_lzo_init(); |
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#endif |
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/* Setting default compression mode */ |
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#ifdef CONFIG_JFFS2_CMODE_NONE |
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jffs2_compression_mode = JFFS2_COMPR_MODE_NONE; |
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jffs2_dbg(1, "default compression mode: none\n"); |
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#else |
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#ifdef CONFIG_JFFS2_CMODE_SIZE |
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jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE; |
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jffs2_dbg(1, "default compression mode: size\n"); |
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#else |
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#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO |
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jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO; |
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jffs2_dbg(1, "default compression mode: favourlzo\n"); |
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#else |
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jffs2_dbg(1, "default compression mode: priority\n"); |
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#endif |
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#endif |
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#endif |
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return 0; |
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} |
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int jffs2_compressors_exit(void) |
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{ |
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/* Unregistering compressors */ |
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#ifdef CONFIG_JFFS2_LZO |
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jffs2_lzo_exit(); |
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#endif |
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#ifdef CONFIG_JFFS2_RUBIN |
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jffs2_dynrubin_exit(); |
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jffs2_rubinmips_exit(); |
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#endif |
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#ifdef CONFIG_JFFS2_RTIME |
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jffs2_rtime_exit(); |
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#endif |
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#ifdef CONFIG_JFFS2_ZLIB |
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jffs2_zlib_exit(); |
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#endif |
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return 0; |
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}
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