fs/jffs2/compr_lzo.c

0001 /*
0002  * JFFS2 -- Journalling Flash File System, Version 2.
0003  *
0004  * Copyright © 2007 Nokia Corporation. All rights reserved.
0005  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
0006  *
0007  * Created by Richard Purdie <rpurdie@openedhand.com>
0008  *
0009  * For licensing information, see the file 'LICENCE' in this directory.
0010  *
0011  */
0012
0013 #include <linux/kernel.h>
0014 #include <linux/sched.h>
0015 #include <linux/vmalloc.h>
0016 #include <linux/init.h>
0017 #include <linux/lzo.h>
0018 #include "compr.h"
0019
0020 static void *lzo_mem;
0021 static void *lzo_compress_buf;
0022 static DEFINE_MUTEX(deflate_mutex); /* for lzo_mem and lzo_compress_buf */
0023
0024 static void free_workspace(void)
0025 {
0026     vfree(lzo_mem);
0027     vfree(lzo_compress_buf);
0028 }
0029
0030 static int __init alloc_workspace(void)
0031 {
0032     lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
0033     lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
0034
0035     if (!lzo_mem || !lzo_compress_buf) {
0036         free_workspace();
0037         return -ENOMEM;
0038     }
0039
0040     return 0;
0041 }
0042
0043 static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
0044                   uint32_t *sourcelen, uint32_t *dstlen)
0045 {
0046     size_t compress_size;
0047     int ret;
0048
0049     mutex_lock(&deflate_mutex);
0050     ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
0051     if (ret != LZO_E_OK)
0052         goto fail;
0053
0054     if (compress_size > *dstlen)
0055         goto fail;
0056
0057     memcpy(cpage_out, lzo_compress_buf, compress_size);
0058     mutex_unlock(&deflate_mutex);
0059
0060     *dstlen = compress_size;
0061     return 0;
0062
0063  fail:
0064     mutex_unlock(&deflate_mutex);
0065     return -1;
0066 }
0067
0068 static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
0069                  uint32_t srclen, uint32_t destlen)
0070 {
0071     size_t dl = destlen;
0072     int ret;
0073
0074     ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl);
0075
0076     if (ret != LZO_E_OK || dl != destlen)
0077         return -1;
0078
0079     return 0;
0080 }
0081
0082 static struct jffs2_compressor jffs2_lzo_comp = {
0083     .priority = JFFS2_LZO_PRIORITY,
0084     .name = "lzo",
0085     .compr = JFFS2_COMPR_LZO,
0086     .compress = &jffs2_lzo_compress,
0087     .decompress = &jffs2_lzo_decompress,
0088     .disabled = 0,
0089 };
0090
0091 int __init jffs2_lzo_init(void)
0092 {
0093     int ret;
0094
0095     ret = alloc_workspace();
0096     if (ret < 0)
0097         return ret;
0098
0099     ret = jffs2_register_compressor(&jffs2_lzo_comp);
0100     if (ret)
0101         free_workspace();
0102
0103     return ret;
0104 }
0105
0106 void jffs2_lzo_exit(void)
0107 {
0108     jffs2_unregister_compressor(&jffs2_lzo_comp);
0109     free_workspace();
0110 }