mirror of https://gitee.com/openkylin/linux.git
361 lines
10 KiB
C
361 lines
10 KiB
C
/*
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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 <dwmw2@infradead.org>
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* Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
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* University of Szeged, Hungary
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*
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* Created by Arjan van de Ven <arjan@infradead.org>
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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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#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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/* 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 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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switch (jffs2_compression_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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output_buf = kmalloc(*cdatalen,GFP_KERNEL);
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if (!output_buf) {
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printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
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goto out;
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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 backwards-compatibility and disabled modules */
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if ((!this->compress)||(this->disabled))
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continue;
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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, output_buf, datalen, cdatalen, NULL);
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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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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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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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printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n", 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, NULL);
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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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}
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spin_unlock(&jffs2_compressor_list_lock);
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break;
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default:
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printk(KERN_ERR "JFFS2: unknown compression mode.\n");
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}
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out:
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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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else {
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*cpage_out = output_buf;
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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, NULL);
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spin_lock(&jffs2_compressor_list_lock);
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if (ret) {
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printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", 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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printk(KERN_WARNING "JFFS2 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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printk(KERN_WARNING "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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D1(printk(KERN_DEBUG "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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D1(printk(KERN_DEBUG "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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printk(KERN_WARNING "JFFS2: Compressor modul 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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D1(printk(KERN_INFO "JFFS2: 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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D1(printk(KERN_INFO "JFFS2: 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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D1(printk(KERN_INFO "JFFS2: default compression mode: favourlzo\n");)
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#else
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D1(printk(KERN_INFO "JFFS2: 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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