diff options
Diffstat (limited to 'kernel/fs/cramfs/uncompress.c')
-rw-r--r-- | kernel/fs/cramfs/uncompress.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/kernel/fs/cramfs/uncompress.c b/kernel/fs/cramfs/uncompress.c new file mode 100644 index 000000000..ec4f1d4fd --- /dev/null +++ b/kernel/fs/cramfs/uncompress.c @@ -0,0 +1,79 @@ +/* + * uncompress.c + * + * (C) Copyright 1999 Linus Torvalds + * + * cramfs interfaces to the uncompression library. There's really just + * three entrypoints: + * + * - cramfs_uncompress_init() - called to initialize the thing. + * - cramfs_uncompress_exit() - tell me when you're done + * - cramfs_uncompress_block() - uncompress a block. + * + * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We + * only have one stream, and we'll initialize it only once even if it + * then is used by multiple filesystems. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/vmalloc.h> +#include <linux/zlib.h> +#include "internal.h" + +static z_stream stream; +static int initialized; + +/* Returns length of decompressed data. */ +int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen) +{ + int err; + + stream.next_in = src; + stream.avail_in = srclen; + + stream.next_out = dst; + stream.avail_out = dstlen; + + err = zlib_inflateReset(&stream); + if (err != Z_OK) { + pr_err("zlib_inflateReset error %d\n", err); + zlib_inflateEnd(&stream); + zlib_inflateInit(&stream); + } + + err = zlib_inflate(&stream, Z_FINISH); + if (err != Z_STREAM_END) + goto err; + return stream.total_out; + +err: + pr_err("Error %d while decompressing!\n", err); + pr_err("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen); + return -EIO; +} + +int cramfs_uncompress_init(void) +{ + if (!initialized++) { + stream.workspace = vmalloc(zlib_inflate_workspacesize()); + if (!stream.workspace) { + initialized = 0; + return -ENOMEM; + } + stream.next_in = NULL; + stream.avail_in = 0; + zlib_inflateInit(&stream); + } + return 0; +} + +void cramfs_uncompress_exit(void) +{ + if (!--initialized) { + zlib_inflateEnd(&stream); + vfree(stream.workspace); + } +} |