Merge tag 'libnvdimm-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdim...
[linux-2.6-microblaze.git] / fs / cramfs / uncompress.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * uncompress.c
4  *
5  * (C) Copyright 1999 Linus Torvalds
6  *
7  * cramfs interfaces to the uncompression library. There's really just
8  * three entrypoints:
9  *
10  *  - cramfs_uncompress_init() - called to initialize the thing.
11  *  - cramfs_uncompress_exit() - tell me when you're done
12  *  - cramfs_uncompress_block() - uncompress a block.
13  *
14  * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
15  * only have one stream, and we'll initialize it only once even if it
16  * then is used by multiple filesystems.
17  */
18
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/vmalloc.h>
24 #include <linux/zlib.h>
25 #include "internal.h"
26
27 static z_stream stream;
28 static int initialized;
29
30 /* Returns length of decompressed data. */
31 int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
32 {
33         int err;
34
35         stream.next_in = src;
36         stream.avail_in = srclen;
37
38         stream.next_out = dst;
39         stream.avail_out = dstlen;
40
41         err = zlib_inflateReset(&stream);
42         if (err != Z_OK) {
43                 pr_err("zlib_inflateReset error %d\n", err);
44                 zlib_inflateEnd(&stream);
45                 zlib_inflateInit(&stream);
46         }
47
48         err = zlib_inflate(&stream, Z_FINISH);
49         if (err != Z_STREAM_END)
50                 goto err;
51         return stream.total_out;
52
53 err:
54         pr_err("Error %d while decompressing!\n", err);
55         pr_err("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
56         return -EIO;
57 }
58
59 int cramfs_uncompress_init(void)
60 {
61         if (!initialized++) {
62                 stream.workspace = vmalloc(zlib_inflate_workspacesize());
63                 if (!stream.workspace) {
64                         initialized = 0;
65                         return -ENOMEM;
66                 }
67                 stream.next_in = NULL;
68                 stream.avail_in = 0;
69                 zlib_inflateInit(&stream);
70         }
71         return 0;
72 }
73
74 void cramfs_uncompress_exit(void)
75 {
76         if (!--initialized) {
77                 zlib_inflateEnd(&stream);
78                 vfree(stream.workspace);
79         }
80 }