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![Jim Keniston](/assets/img/avatar_default.png)
Instead of always creating a huge (268K) deflate_workspace with the maximum compression parameters (windowBits=15, memLevel=8), allow the caller to obtain a smaller workspace by specifying smaller parameter values. For example, when capturing oops and panic reports to a medium with limited capacity, such as NVRAM, compression may be the only way to capture the whole report. In this case, a small workspace (24K works fine) is a win, whether you allocate the workspace when you need it (i.e., during an oops or panic) or at boot time. I've verified that this patch works with all accepted values of windowBits (positive and negative), memLevel, and compression level. Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David Miller <davem@davemloft.net> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
218 lines
5.8 KiB
C
218 lines
5.8 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2001-2007 Red Hat, Inc.
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* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#if !defined(__KERNEL__) && !defined(__ECOS)
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#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
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#endif
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#include <linux/kernel.h>
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#include <linux/zlib.h>
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#include <linux/zutil.h>
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#include "nodelist.h"
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#include "compr.h"
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/* Plan: call deflate() with avail_in == *sourcelen,
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avail_out = *dstlen - 12 and flush == Z_FINISH.
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If it doesn't manage to finish, call it again with
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avail_in == 0 and avail_out set to the remaining 12
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bytes for it to clean up.
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Q: Is 12 bytes sufficient?
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*/
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#define STREAM_END_SPACE 12
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static DEFINE_MUTEX(deflate_mutex);
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static DEFINE_MUTEX(inflate_mutex);
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static z_stream inf_strm, def_strm;
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#ifdef __KERNEL__ /* Linux-only */
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/mutex.h>
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static int __init alloc_workspaces(void)
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{
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def_strm.workspace = vmalloc(zlib_deflate_workspacesize(MAX_WBITS,
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MAX_MEM_LEVEL));
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if (!def_strm.workspace) {
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printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL));
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return -ENOMEM;
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}
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D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL)));
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inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
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if (!inf_strm.workspace) {
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printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
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vfree(def_strm.workspace);
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return -ENOMEM;
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}
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D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
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return 0;
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}
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static void free_workspaces(void)
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{
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vfree(def_strm.workspace);
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vfree(inf_strm.workspace);
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}
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#else
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#define alloc_workspaces() (0)
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#define free_workspaces() do { } while(0)
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#endif /* __KERNEL__ */
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static int jffs2_zlib_compress(unsigned char *data_in,
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unsigned char *cpage_out,
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uint32_t *sourcelen, uint32_t *dstlen)
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{
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int ret;
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if (*dstlen <= STREAM_END_SPACE)
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return -1;
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mutex_lock(&deflate_mutex);
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if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
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printk(KERN_WARNING "deflateInit failed\n");
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mutex_unlock(&deflate_mutex);
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return -1;
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}
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def_strm.next_in = data_in;
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def_strm.total_in = 0;
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def_strm.next_out = cpage_out;
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def_strm.total_out = 0;
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while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
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def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
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def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
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D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
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def_strm.avail_in, def_strm.avail_out));
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ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
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D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
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def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
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if (ret != Z_OK) {
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D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
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zlib_deflateEnd(&def_strm);
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mutex_unlock(&deflate_mutex);
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return -1;
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}
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}
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def_strm.avail_out += STREAM_END_SPACE;
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def_strm.avail_in = 0;
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ret = zlib_deflate(&def_strm, Z_FINISH);
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zlib_deflateEnd(&def_strm);
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if (ret != Z_STREAM_END) {
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D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
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ret = -1;
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goto out;
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}
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if (def_strm.total_out >= def_strm.total_in) {
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D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
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def_strm.total_in, def_strm.total_out));
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ret = -1;
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goto out;
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}
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D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
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def_strm.total_in, def_strm.total_out));
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*dstlen = def_strm.total_out;
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*sourcelen = def_strm.total_in;
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ret = 0;
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out:
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mutex_unlock(&deflate_mutex);
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return ret;
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}
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static int jffs2_zlib_decompress(unsigned char *data_in,
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unsigned char *cpage_out,
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uint32_t srclen, uint32_t destlen)
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{
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int ret;
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int wbits = MAX_WBITS;
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mutex_lock(&inflate_mutex);
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inf_strm.next_in = data_in;
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inf_strm.avail_in = srclen;
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inf_strm.total_in = 0;
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inf_strm.next_out = cpage_out;
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inf_strm.avail_out = destlen;
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inf_strm.total_out = 0;
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/* If it's deflate, and it's got no preset dictionary, then
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we can tell zlib to skip the adler32 check. */
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if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
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((data_in[0] & 0x0f) == Z_DEFLATED) &&
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!(((data_in[0]<<8) + data_in[1]) % 31)) {
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D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
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wbits = -((data_in[0] >> 4) + 8);
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inf_strm.next_in += 2;
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inf_strm.avail_in -= 2;
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} else {
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/* Let this remain D1 for now -- it should never happen */
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D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
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}
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if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
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printk(KERN_WARNING "inflateInit failed\n");
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mutex_unlock(&inflate_mutex);
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return 1;
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}
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while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
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;
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if (ret != Z_STREAM_END) {
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printk(KERN_NOTICE "inflate returned %d\n", ret);
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}
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zlib_inflateEnd(&inf_strm);
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mutex_unlock(&inflate_mutex);
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return 0;
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}
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static struct jffs2_compressor jffs2_zlib_comp = {
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.priority = JFFS2_ZLIB_PRIORITY,
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.name = "zlib",
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.compr = JFFS2_COMPR_ZLIB,
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.compress = &jffs2_zlib_compress,
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.decompress = &jffs2_zlib_decompress,
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#ifdef JFFS2_ZLIB_DISABLED
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.disabled = 1,
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#else
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.disabled = 0,
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#endif
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};
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int __init jffs2_zlib_init(void)
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{
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int ret;
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ret = alloc_workspaces();
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if (ret)
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return ret;
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ret = jffs2_register_compressor(&jffs2_zlib_comp);
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if (ret)
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free_workspaces();
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return ret;
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}
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void jffs2_zlib_exit(void)
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{
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jffs2_unregister_compressor(&jffs2_zlib_comp);
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free_workspaces();
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}
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