diff options
Diffstat (limited to 'cpukit/libfs/src/jffs2/src/compr.c')
| -rw-r--r-- | cpukit/libfs/src/jffs2/src/compr.c | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/cpukit/libfs/src/jffs2/src/compr.c b/cpukit/libfs/src/jffs2/src/compr.c new file mode 100644 index 0000000000..4849a4c9a0 --- /dev/null +++ b/cpukit/libfs/src/jffs2/src/compr.c @@ -0,0 +1,418 @@ +/* + * JFFS2 -- Journalling Flash File System, Version 2. + * + * Copyright © 2001-2007 Red Hat, Inc. + * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org> + * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>, + * University of Szeged, Hungary + * + * Created by Arjan van de Ven <arjan@infradead.org> + * + * For licensing information, see the file 'LICENCE' in this directory. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include "compr.h" + +static DEFINE_SPINLOCK(jffs2_compressor_list_lock); + +/* Available compressors are on this list */ +static LIST_HEAD(jffs2_compressor_list); + +/* Actual compression mode */ +static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY; + +/* Statistics for blocks stored without compression */ +static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0; + + +/* + * Return 1 to use this compression + */ +static int jffs2_is_best_compression(struct jffs2_compressor *this, + struct jffs2_compressor *best, uint32_t size, uint32_t bestsize) +{ + switch (jffs2_compression_mode) { + case JFFS2_COMPR_MODE_SIZE: + if (bestsize > size) + return 1; + return 0; + case JFFS2_COMPR_MODE_FAVOURLZO: + if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size)) + return 1; + if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size)) + return 1; + if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100))) + return 1; + if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size) + return 1; + + return 0; + } + /* Shouldn't happen */ + return 0; +} + +/* + * jffs2_selected_compress: + * @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB). + * If 0, just take the first available compression mode. + * @data_in: Pointer to uncompressed data + * @cpage_out: Pointer to returned pointer to buffer for compressed data + * @datalen: On entry, holds the amount of data available for compression. + * On exit, expected to hold the amount of data actually compressed. + * @cdatalen: On entry, holds the amount of space available for compressed + * data. On exit, expected to hold the actual size of the compressed + * data. + * + * Returns: the compression type used. Zero is used to show that the data + * could not be compressed; probably because we couldn't find the requested + * compression mode. + */ +static int jffs2_selected_compress(u8 compr, unsigned char *data_in, + unsigned char **cpage_out, u32 *datalen, u32 *cdatalen) +{ + struct jffs2_compressor *this; + int err, ret = JFFS2_COMPR_NONE; + uint32_t orig_slen, orig_dlen; + char *output_buf; + + output_buf = kmalloc(*cdatalen, GFP_KERNEL); + if (!output_buf) { + pr_warn("No memory for compressor allocation. Compression failed.\n"); + return ret; + } + orig_slen = *datalen; + orig_dlen = *cdatalen; + spin_lock(&jffs2_compressor_list_lock); + list_for_each_entry(this, &jffs2_compressor_list, list) { + /* Skip decompress-only and disabled modules */ + if (!this->compress || this->disabled) + continue; + + /* Skip if not the desired compression type */ + if (compr && (compr != this->compr)) + continue; + + /* + * Either compression type was unspecified, or we found our + * compressor; either way, we're good to go. + */ + this->usecount++; + spin_unlock(&jffs2_compressor_list_lock); + + *datalen = orig_slen; + *cdatalen = orig_dlen; + err = this->compress(data_in, output_buf, datalen, cdatalen); + + spin_lock(&jffs2_compressor_list_lock); + this->usecount--; + if (!err) { + /* Success */ + ret = this->compr; + this->stat_compr_blocks++; + this->stat_compr_orig_size += *datalen; + this->stat_compr_new_size += *cdatalen; + break; + } + } + spin_unlock(&jffs2_compressor_list_lock); + if (ret == JFFS2_COMPR_NONE) + kfree(output_buf); + else + *cpage_out = output_buf; + + return ret; +} + +/* jffs2_compress: + * @data_in: Pointer to uncompressed data + * @cpage_out: Pointer to returned pointer to buffer for compressed data + * @datalen: On entry, holds the amount of data available for compression. + * On exit, expected to hold the amount of data actually compressed. + * @cdatalen: On entry, holds the amount of space available for compressed + * data. On exit, expected to hold the actual size of the compressed + * data. + * + * Returns: Lower byte to be stored with data indicating compression type used. + * Zero is used to show that the data could not be compressed - the + * compressed version was actually larger than the original. + * Upper byte will be used later. (soon) + * + * If the cdata buffer isn't large enough to hold all the uncompressed data, + * jffs2_compress should compress as much as will fit, and should set + * *datalen accordingly to show the amount of data which were compressed. + */ +uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, + unsigned char *data_in, unsigned char **cpage_out, + uint32_t *datalen, uint32_t *cdatalen) +{ + int ret = JFFS2_COMPR_NONE; + int mode, compr_ret; + struct jffs2_compressor *this, *best=NULL; + unsigned char *output_buf = NULL, *tmp_buf; + uint32_t orig_slen, orig_dlen; + uint32_t best_slen=0, best_dlen=0; + + if (c->mount_opts.override_compr) + mode = c->mount_opts.compr; + else + mode = jffs2_compression_mode; + + switch (mode) { + case JFFS2_COMPR_MODE_NONE: + break; + case JFFS2_COMPR_MODE_PRIORITY: + ret = jffs2_selected_compress(0, data_in, cpage_out, datalen, + cdatalen); + break; + case JFFS2_COMPR_MODE_SIZE: + case JFFS2_COMPR_MODE_FAVOURLZO: + orig_slen = *datalen; + orig_dlen = *cdatalen; + spin_lock(&jffs2_compressor_list_lock); + list_for_each_entry(this, &jffs2_compressor_list, list) { + /* Skip decompress-only backwards-compatibility and disabled modules */ + if ((!this->compress)||(this->disabled)) + continue; + /* Allocating memory for output buffer if necessary */ + if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) { + spin_unlock(&jffs2_compressor_list_lock); + kfree(this->compr_buf); + spin_lock(&jffs2_compressor_list_lock); + this->compr_buf_size=0; + this->compr_buf=NULL; + } + if (!this->compr_buf) { + spin_unlock(&jffs2_compressor_list_lock); + tmp_buf = kmalloc(orig_slen, GFP_KERNEL); + spin_lock(&jffs2_compressor_list_lock); + if (!tmp_buf) { + pr_warn("No memory for compressor allocation. (%d bytes)\n", + orig_slen); + continue; + } + else { + this->compr_buf = tmp_buf; + this->compr_buf_size = orig_slen; + } + } + this->usecount++; + spin_unlock(&jffs2_compressor_list_lock); + *datalen = orig_slen; + *cdatalen = orig_dlen; + compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen); + spin_lock(&jffs2_compressor_list_lock); + this->usecount--; + if (!compr_ret) { + if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen)) + && (*cdatalen < *datalen)) { + best_dlen = *cdatalen; + best_slen = *datalen; + best = this; + } + } + } + if (best_dlen) { + *cdatalen = best_dlen; + *datalen = best_slen; + output_buf = best->compr_buf; + best->compr_buf = NULL; + best->compr_buf_size = 0; + best->stat_compr_blocks++; + best->stat_compr_orig_size += best_slen; + best->stat_compr_new_size += best_dlen; + ret = best->compr; + *cpage_out = output_buf; + } + spin_unlock(&jffs2_compressor_list_lock); + break; + case JFFS2_COMPR_MODE_FORCELZO: + ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in, + cpage_out, datalen, cdatalen); + break; + case JFFS2_COMPR_MODE_FORCEZLIB: + ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in, + cpage_out, datalen, cdatalen); + break; + default: + pr_err("unknown compression mode\n"); + } + + if (ret == JFFS2_COMPR_NONE) { + *cpage_out = data_in; + *datalen = *cdatalen; + none_stat_compr_blocks++; + none_stat_compr_size += *datalen; + } + return ret; +} + +int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, + uint16_t comprtype, unsigned char *cdata_in, + unsigned char *data_out, uint32_t cdatalen, uint32_t datalen) +{ + struct jffs2_compressor *this; + int ret; + + /* Older code had a bug where it would write non-zero 'usercompr' + fields. Deal with it. */ + if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB) + comprtype &= 0xff; + + switch (comprtype & 0xff) { + case JFFS2_COMPR_NONE: + /* This should be special-cased elsewhere, but we might as well deal with it */ + memcpy(data_out, cdata_in, datalen); + none_stat_decompr_blocks++; + break; + case JFFS2_COMPR_ZERO: + memset(data_out, 0, datalen); + break; + default: + spin_lock(&jffs2_compressor_list_lock); + list_for_each_entry(this, &jffs2_compressor_list, list) { + if (comprtype == this->compr) { + this->usecount++; + spin_unlock(&jffs2_compressor_list_lock); + ret = this->decompress(cdata_in, data_out, cdatalen, datalen); + spin_lock(&jffs2_compressor_list_lock); + if (ret) { + pr_warn("Decompressor \"%s\" returned %d\n", + this->name, ret); + } + else { + this->stat_decompr_blocks++; + } + this->usecount--; + spin_unlock(&jffs2_compressor_list_lock); + return ret; + } + } + pr_warn("compression type 0x%02x not available\n", comprtype); + spin_unlock(&jffs2_compressor_list_lock); + return -EIO; + } + return 0; +} + +int jffs2_register_compressor(struct jffs2_compressor *comp) +{ + struct jffs2_compressor *this; + + if (!comp->name) { + pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n"); + return -1; + } + comp->compr_buf_size=0; + comp->compr_buf=NULL; + comp->usecount=0; + comp->stat_compr_orig_size=0; + comp->stat_compr_new_size=0; + comp->stat_compr_blocks=0; + comp->stat_decompr_blocks=0; + jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name); + + spin_lock(&jffs2_compressor_list_lock); + + list_for_each_entry(this, &jffs2_compressor_list, list) { + if (this->priority < comp->priority) { + list_add(&comp->list, this->list.prev); + goto out; + } + } + list_add_tail(&comp->list, &jffs2_compressor_list); +out: + D2(list_for_each_entry(this, &jffs2_compressor_list, list) { + printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); + }) + + spin_unlock(&jffs2_compressor_list_lock); + + return 0; +} + +int jffs2_unregister_compressor(struct jffs2_compressor *comp) +{ + D2(struct jffs2_compressor *this); + + jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name); + + spin_lock(&jffs2_compressor_list_lock); + + if (comp->usecount) { + spin_unlock(&jffs2_compressor_list_lock); + pr_warn("Compressor module is in use. Unregister failed.\n"); + return -1; + } + list_del(&comp->list); + + D2(list_for_each_entry(this, &jffs2_compressor_list, list) { + printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); + }) + spin_unlock(&jffs2_compressor_list_lock); + return 0; +} + +void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig) +{ + if (orig != comprbuf) + kfree(comprbuf); +} + +int __init jffs2_compressors_init(void) +{ +/* Registering compressors */ +#ifdef CONFIG_JFFS2_ZLIB + jffs2_zlib_init(); +#endif +#ifdef CONFIG_JFFS2_RTIME + jffs2_rtime_init(); +#endif +#ifdef CONFIG_JFFS2_RUBIN + jffs2_rubinmips_init(); + jffs2_dynrubin_init(); +#endif +#ifdef CONFIG_JFFS2_LZO + jffs2_lzo_init(); +#endif +/* Setting default compression mode */ +#ifdef CONFIG_JFFS2_CMODE_NONE + jffs2_compression_mode = JFFS2_COMPR_MODE_NONE; + jffs2_dbg(1, "default compression mode: none\n"); +#else +#ifdef CONFIG_JFFS2_CMODE_SIZE + jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE; + jffs2_dbg(1, "default compression mode: size\n"); +#else +#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO + jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO; + jffs2_dbg(1, "default compression mode: favourlzo\n"); +#else + jffs2_dbg(1, "default compression mode: priority\n"); +#endif +#endif +#endif + return 0; +} + +int jffs2_compressors_exit(void) +{ +/* Unregistering compressors */ +#ifdef CONFIG_JFFS2_LZO + jffs2_lzo_exit(); +#endif +#ifdef CONFIG_JFFS2_RUBIN + jffs2_dynrubin_exit(); + jffs2_rubinmips_exit(); +#endif +#ifdef CONFIG_JFFS2_RTIME + jffs2_rtime_exit(); +#endif +#ifdef CONFIG_JFFS2_ZLIB + jffs2_zlib_exit(); +#endif + return 0; +} |