cregit-Linux how code gets into the kernel

Release 4.10 fs/jffs2/compr.c

Directory: fs/jffs2
/*
 * 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; }

Contributors

PersonTokensPropCommitsCommitProp
richard purdierichard purdie131100.00%1100.00%
Total131100.00%1100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse17072.34%233.33%
andres salomonandres salomon4619.57%116.67%
linus torvaldslinus torvalds177.23%116.67%
joe perchesjoe perches20.85%233.33%
Total235100.00%6100.00%

/* 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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse33563.09%120.00%
andres salomonandres salomon16831.64%120.00%
richard purdierichard purdie244.52%120.00%
joe perchesjoe perches40.75%240.00%
Total531100.00%5100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse21098.59%250.00%
joe perchesjoe perches31.41%250.00%
Total213100.00%4100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse15597.48%250.00%
joe perchesjoe perches42.52%250.00%
Total159100.00%4100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse7187.65%240.00%
joe perchesjoe perches1012.35%360.00%
Total81100.00%5100.00%


void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig) { if (orig != comprbuf) kfree(comprbuf); }

Contributors

PersonTokensPropCommitsCommitProp
linus torvaldslinus torvalds1557.69%150.00%
david woodhousedavid woodhouse1142.31%150.00%
Total26100.00%2100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse4944.95%112.50%
richard purdierichard purdie2119.27%225.00%
joe perchesjoe perches2018.35%225.00%
linus torvaldslinus torvalds1816.51%225.00%
david brownelldavid brownell10.92%112.50%
Total109100.00%8100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse3473.91%133.33%
richard purdierichard purdie817.39%133.33%
linus torvaldslinus torvalds48.70%133.33%
Total46100.00%3100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
david woodhousedavid woodhouse106967.66%533.33%
andres salomonandres salomon21613.67%16.67%
richard purdierichard purdie18511.71%213.33%
linus torvaldslinus torvalds553.48%213.33%
joe perchesjoe perches503.16%320.00%
thomas gleixnerthomas gleixner40.25%16.67%
david brownelldavid brownell10.06%16.67%
Total1580100.00%15100.00%
Directory: fs/jffs2
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