Root/fs/jffs2/compr_zlib.c

1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 *
6 * Created by David Woodhouse <dwmw2@infradead.org>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
11
12#if !defined(__KERNEL__) && !defined(__ECOS)
13#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
14#endif
15
16#include <linux/kernel.h>
17#include <linux/slab.h>
18#include <linux/zlib.h>
19#include <linux/zutil.h>
20#include "nodelist.h"
21#include "compr.h"
22
23    /* Plan: call deflate() with avail_in == *sourcelen,
24        avail_out = *dstlen - 12 and flush == Z_FINISH.
25        If it doesn't manage to finish, call it again with
26        avail_in == 0 and avail_out set to the remaining 12
27        bytes for it to clean up.
28       Q: Is 12 bytes sufficient?
29    */
30#define STREAM_END_SPACE 12
31
32static DEFINE_MUTEX(deflate_mutex);
33static DEFINE_MUTEX(inflate_mutex);
34static z_stream inf_strm, def_strm;
35
36#ifdef __KERNEL__ /* Linux-only */
37#include <linux/vmalloc.h>
38#include <linux/init.h>
39#include <linux/mutex.h>
40
41static int __init alloc_workspaces(void)
42{
43    def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
44    if (!def_strm.workspace) {
45        printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
46        return -ENOMEM;
47    }
48    D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
49    inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
50    if (!inf_strm.workspace) {
51        printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
52        vfree(def_strm.workspace);
53        return -ENOMEM;
54    }
55    D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
56    return 0;
57}
58
59static void free_workspaces(void)
60{
61    vfree(def_strm.workspace);
62    vfree(inf_strm.workspace);
63}
64#else
65#define alloc_workspaces() (0)
66#define free_workspaces() do { } while(0)
67#endif /* __KERNEL__ */
68
69static int jffs2_zlib_compress(unsigned char *data_in,
70                   unsigned char *cpage_out,
71                   uint32_t *sourcelen, uint32_t *dstlen,
72                   void *model)
73{
74    int ret;
75
76    if (*dstlen <= STREAM_END_SPACE)
77        return -1;
78
79    mutex_lock(&deflate_mutex);
80
81    if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
82        printk(KERN_WARNING "deflateInit failed\n");
83        mutex_unlock(&deflate_mutex);
84        return -1;
85    }
86
87    def_strm.next_in = data_in;
88    def_strm.total_in = 0;
89
90    def_strm.next_out = cpage_out;
91    def_strm.total_out = 0;
92
93    while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
94        def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
95        def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
96        D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
97              def_strm.avail_in, def_strm.avail_out));
98        ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
99        D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
100              def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
101        if (ret != Z_OK) {
102            D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
103            zlib_deflateEnd(&def_strm);
104            mutex_unlock(&deflate_mutex);
105            return -1;
106        }
107    }
108    def_strm.avail_out += STREAM_END_SPACE;
109    def_strm.avail_in = 0;
110    ret = zlib_deflate(&def_strm, Z_FINISH);
111    zlib_deflateEnd(&def_strm);
112
113    if (ret != Z_STREAM_END) {
114        D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
115        ret = -1;
116        goto out;
117    }
118
119    if (def_strm.total_out >= def_strm.total_in) {
120        D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
121              def_strm.total_in, def_strm.total_out));
122        ret = -1;
123        goto out;
124    }
125
126    D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
127          def_strm.total_in, def_strm.total_out));
128
129    *dstlen = def_strm.total_out;
130    *sourcelen = def_strm.total_in;
131    ret = 0;
132 out:
133    mutex_unlock(&deflate_mutex);
134    return ret;
135}
136
137static int jffs2_zlib_decompress(unsigned char *data_in,
138                 unsigned char *cpage_out,
139                 uint32_t srclen, uint32_t destlen,
140                 void *model)
141{
142    int ret;
143    int wbits = MAX_WBITS;
144
145    mutex_lock(&inflate_mutex);
146
147    inf_strm.next_in = data_in;
148    inf_strm.avail_in = srclen;
149    inf_strm.total_in = 0;
150
151    inf_strm.next_out = cpage_out;
152    inf_strm.avail_out = destlen;
153    inf_strm.total_out = 0;
154
155    /* If it's deflate, and it's got no preset dictionary, then
156       we can tell zlib to skip the adler32 check. */
157    if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
158        ((data_in[0] & 0x0f) == Z_DEFLATED) &&
159        !(((data_in[0]<<8) + data_in[1]) % 31)) {
160
161        D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
162        wbits = -((data_in[0] >> 4) + 8);
163        inf_strm.next_in += 2;
164        inf_strm.avail_in -= 2;
165    } else {
166        /* Let this remain D1 for now -- it should never happen */
167        D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
168    }
169
170
171    if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
172        printk(KERN_WARNING "inflateInit failed\n");
173        mutex_unlock(&inflate_mutex);
174        return 1;
175    }
176
177    while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
178        ;
179    if (ret != Z_STREAM_END) {
180        printk(KERN_NOTICE "inflate returned %d\n", ret);
181    }
182    zlib_inflateEnd(&inf_strm);
183    mutex_unlock(&inflate_mutex);
184    return 0;
185}
186
187static struct jffs2_compressor jffs2_zlib_comp = {
188    .priority = JFFS2_ZLIB_PRIORITY,
189    .name = "zlib",
190    .compr = JFFS2_COMPR_ZLIB,
191    .compress = &jffs2_zlib_compress,
192    .decompress = &jffs2_zlib_decompress,
193#ifdef JFFS2_ZLIB_DISABLED
194    .disabled = 1,
195#else
196    .disabled = 0,
197#endif
198};
199
200int __init jffs2_zlib_init(void)
201{
202    int ret;
203
204    ret = alloc_workspaces();
205    if (ret)
206        return ret;
207
208    ret = jffs2_register_compressor(&jffs2_zlib_comp);
209    if (ret)
210        free_workspaces();
211
212    return ret;
213}
214
215void jffs2_zlib_exit(void)
216{
217    jffs2_unregister_compressor(&jffs2_zlib_comp);
218    free_workspaces();
219}
220

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